Linezolid formulation

Abstract

To provide a composition for relieving and / or treating chronic lower back pain (CLBP).SOLUTION: The present invention provides an injectable pharmaceutical formulation for relieving and / or treating chronic lower back pain (CLBP) comprising an effective dose of linezolid, a thermosensitive hydrogel comprising poloxamer and iohexol, and optionally (c) at least one pharmaceutically acceptable additive, and the linezolid forms a suspension in the thermosensitive hydrogel.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention provides linezolid formulations, methods, and manufactures useful for treating chronic low back pain. In one aspect of the invention, the linezolid formulation comprises linezolid form II suspension, iohexol, and poloxamer 407, and is injectable. [Background technology]

[0002] Chronic low back pain (CLBP) is common among the general population worldwide. A positive association between Modic changes (bone edema) on MRI and non-specific LBP has been found with a mean odds ratio of 4.5. Jensen et al. reviewed that the prevalence of any type of Modic change (e.g., types I-III) in patients with non-specific CLBP was 46% compared to 6% in the general population (Non-Patent Document 1).

[0003] Modic changes, characterized by vertebral edema (or inflammation), may be caused by low-grade infection of disc tissue, where disc / endplate damage and persistent inflammatory stimuli create a predisposing condition. Propionibacterium acnes (P. acnes) in non-suppurative intervertebral discs has been found to be one of the pathogens causing Modic changes (e.g., type I) and nonspecific low back pain (Non-Patent Document 2, Non-Patent Document 3, Non-Patent Document 4, Non-Patent Document 5, and Non-Patent Document 6). Intervertebral disc cells may develop an inflammatory response to P. acnes infection (Non-Patent Document 7). P. acnes isolated from patients with Modic changes and disc degeneration may induce inflammatory responses, disc degeneration, and Modic changes when inoculated into an intervertebral disc (Non-Patent Document 8, Non-Patent Document 9, and Non-Patent Document 10). Studies performed in animals also show that P. acnes infection in the intervertebral disc may induce degeneration and Modic changes of the disc (Non-Patent Document 11, Non-Patent Document 12, and Non-Patent Document 13). Strains of P. acnes associated with tissue infection also express hyaluronan degrading enzymes that may contribute to disc degeneration (Non-Patent Document 14).

[0004] It has been hypothesized that anaerobic bacteria (such as P. acnes) from the mouth and skin may reach the disc. Local inflammation in the adjacent bone may be a secondary effect due to the production of cytokines and propionic acid, infection in the disc, and Modic changes are a "side effect" appearing in the bone (4).

[0005] Antibiotic therapy may be effective in treating CLBP with Modic changes. Several studies have shown that oral administration of antibiotics such as amoxicillin-clavulanate can result in clinically important and statistically significant (p<0.001) improvements in all endpoints in patients with chronic LBP (Non-Patent Document 15 and Non-Patent Document 16). This result supports the hypothesis that bacterial infection may play a role in CLBP with Modic changes. [Prior art documents] [Non-patent literature]

[0006] [Non-Patent Document 1] Jensen et al., Eur. Spine J. 2008, vol. 17: 1407-1422 [Non-Patent Document 2] Stirling et al., Lancet, 2001, 357:2024-2025 [Non-Patent Document 3] Agarwal et al., Spine J. 2010, Vol. 10: p. S45-S46 [Non-Patent Document 4] Albert et al., Eur Spine J., 2013, Vol. 22(4): pp. 690-696 [Non-Patent Document 5] Capoor et al., PLoS One, 2016, vol. 11(no. 8):e0161676.doi:10.1371 [Non-Patent Document 6] Capoor et al., PLos One, 2017, Vol. 12(No. 4):e0174518.doi:10.1371 [Non-Patent Document 7] Dudli et al., Eur Spine J., September 7, 2017, doi:10.1007 / s00586-017-5291-4 [Non-Patent Document 8] Chen et al., Biomed Res Int. 2016:9612437. doi:10.1155 / 2016 / 9612437. Epub 2016-01-26 [Non-Patent Document 9] Chen et al., Int Orthop. 2016, Vol. 40(No. 6): pp. 1291-1298 [Non-Patent Document 10] Dudli et al., J Orthop Res. 2016, Vol. 34(No. 8): pp. 1447-1455 [Non-Patent Document 11] Zamora et al., Orthop Traumatol Surg Res., 2017, Vol. 103 (No. 5): pp. 795-799 [Non-Patent Document 12] Shan et al., Spine, April 10, 2017.doi:10.1097 / BRS.0000000000002192 [Non-Patent Document 13] Shan et al., J Bone Joint Am., 2017, Vol. 99 (No. 6): pp. 472-481 [Non-Patent Document 14] Nazipi et al., Microorganisms. 2017 Sep 12; Volume 5 (Number 3). pii:E57.doi:10.3390 / microorganisms5030057 [Non-Patent Document 15] Albert et al., Br. J. Sports Med., 2008, Vol. 42 (No. 12): pp. 969-973 [Non-Patent Document 16] Albert et al., Eur Spine J. 2013, Vol. 22(4): pp. 697-707 Summary of the Invention [Problem to be solved by the invention]

[0007] Although some non-surgical treatment approaches (e.g., intradiscal injections of steroids, anti-TNF-α antibodies, and bisphosphonates) have shown short-term efficacy in reducing Modic changes and CLBP in non-reproducible clinical studies, none of these approaches have been successful and have produced controversial results. Against this background, there is a need in the art for therapies to address the treatment, reduction, prevention, and / or alleviation of pain associated with bone, joint, ligament, and / or tendon diseases, conditions, or disorders, particularly those involving Modic changes or bone edema. The present invention provides a linezolid formulation to meet this need. Linezolid is an antibiotic used to treat infections caused by gram-positive bacteria that are resistant to other antibiotics. P. acnes clinical isolates resistant to linezolid (MIC>4 μg / ml) have not been reported frequently. This formulation of linezolid effectively delivers linezolid to the affected discs and vertebrae, thus improving the efficacy of treating Modic changes and CLBP. [Means for solving the problem]

[0008] The present invention provides injectable formulations suitable for delivery of linezolid to infected spinal sites to treat, prevent, ameliorate, and / or alleviate one or more of the pain or phenotypic manifestations associated with clinical conditions of bones, joints, ligaments, or tendons. Kits, packages, and methods of making and using the same are also provided.

[0009] In the present invention, the linezolid formulation is prepared as a suspension that forms a hydrogel in situ in response to warm body temperature. The formulation of the present invention is both thermosensitive and injectable. In some embodiments, the formulations of the invention include an effective amount of linezolid. In some aspects, the linezolid is linezolid Form II, which is prepared as a particulate suspension in the formulation. Linezolid may be loaded into a delivery vehicle (i.e., hydrogel) to form a suspension that is about 1% to about 20%, preferably about 2.5% to about 20%, by weight or volume of the final formulation. In some examples, the suspension formulation may include about 25 mg / ml, about 30 mg / ml, about 35 mg / ml, about 40 mg / ml, about 45 mg / ml, about 50 mg / ml, about 55 mg / ml, about 60 mg / ml, about 65 mg / ml, about 70 mg / ml, about 75 mg / ml, about 80 mg / ml, about 85 mg / ml, about 90 mg / ml, about 95 mg / ml, about 100 mg / ml, about 150 mg / ml, or about 200 mg / ml of linezolid.

[0010] In some embodiments, the linezolid formulations of the invention include a poloxamer as a delivery vehicle that forms a hydrogel in response to an increase in temperature. In some aspects, the poloxamer is poloxamer 407. The linezolid formulations of the invention may include poloxamer 407 at about 9.5% to about 17% by weight of the formulation, or may include poloxamer 407 at about 9.5% to about 14.5% by weight of the formulation, or may include poloxamer 407 at about 10.5% to about 13.5% by weight of the formulation, or may include poloxamer 407 at a concentration of about 115 mg / ml to about 207 mg / ml in the formulation, or may include poloxamer 407 at a concentration of about 130 mg / ml to about 165 mg / ml in the formulation. Preferably, the linezolid formulation may contain poloxamer 407 at about 10.8% to about 12.8% by weight of the formulation, or at a concentration of about 130 mg / ml to 156 mg / ml in the formulation.

[0011] In some embodiments, the linezolid formulation of the invention includes a radiopaque dye. In some aspects, the agent is iohexol. The linezolid formulation may include iohexol at about 14% to about 59% by weight of the formulation, or at about 14% to about 40% by weight of the formulation, or at a concentration of about 165 mg / ml to about 718 mg / ml in the formulation, or at a concentration of about 200 mg / ml to about 450 mg / ml in the formulation. Preferably, the linezolid formulation may include iohexol at about 17% to about 30% by weight of the formulation, or at a concentration of about 206 mg / ml to about 364 mg / ml in the formulation.

[0012] In a preferred embodiment, the linezolid formulation comprises about 2.5% to about 20% linezolid Form II by weight or volume of the final formulation, and a delivery vehicle (also known as a diluent) comprising about 10.8% to about 12.8% poloxamer 407 by weight of the formulation, and about 17% to about 30% iohexol by weight of the formulation. The formulation is a linezolid suspension. The linezolid formulation is injectable and has a sol-gel transition temperature of about 26° C. to about 36° C.

[0013] The formulations of the present invention may be applied to the lumbar disc and / or adjacent vertebrae, ligaments, muscles, tendons, and joints as needed, and may be performed by open surgery or injection, or by microsurgical or percutaneous techniques.

[0014] In some embodiments, the present invention provides methods of making and using the linezolid formulations. In some examples, the linezolid formulation may be packaged separately, for example, a dose of linezolid powder and a solution of a delivery vehicle containing poloxamer 407 and iohexol in an optimal concentration ratio. The suspension may be prepared by mixing the linezolid powder with the poloxamer vehicle prior to administration. Also provided herein are kits that include the compositions, vehicles, and syringes and / or needles for administration of the sterile injectable formulations. [Brief description of the drawings]

[0015] [Figure 1A] FIG. 1 shows the particle size distribution of Linezolid (Form II) after micronization. [Figure 1B] Representative images of linezolid form II before and after micronization. [Diagram 2] An image showing the needle positioned in the adjacent disc and 0.1 ml of the iohexol-containing formulation injected. The location of the injected formulation can be observed using x-ray or fluoroscopic imaging. [Diagram 3] FIG. 10: Amount of linezolid recovered from sheep intervertebral discs following intradiscal administration. Each point represents the mean and standard error of the mean based on 3-4 discs. [Figure 4] FIG. 1 shows bacteria isolated from linezolid-treated discs compared to untreated discs. [Diagram 5] Figure 1 shows the injectability performance of linezolid suspension (PP353) through pre-warmed sweet potato. [Figure 6] Pharmacokinetics of linezolid in sheep administered PP353 linezolid suspension. Y-axis represents plasma linezolid concentration (ng / ml). X represents time (hours). DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016] The foregoing has outlined rather broadly the features and technical advantages of the present invention in order that the detailed description of the invention that follows may be better understood. Additional features and advantages of the invention will be described hereinafter which form the subject matter of the claims of the invention. Those skilled in the art should appreciate that the conception and specific embodiments disclosed may be readily utilized as a basis for modifying or designing other structures for carrying out the same purposes of the present invention. Those skilled in the art should also realize that such equivalent constructions do not depart from the spirit and scope of the invention as set forth in the appended claims. The novel features which are believed to be characteristic of the present invention, both as to its organization and method of operation, together with further objects and advantages thereof, will be better understood from the following description when considered in connection with the accompanying drawings. It is to be expressly understood, however, that the figures are provided for the purpose of illustration and description only and are not intended as a definition of the limits of the invention.

[0017] The present invention is based on the discovery in human studies that chronic low back pain (CLBP) is often accompanied by Modic changes and herniated discs where bacterial infections are observed. Therefore, pharmaceutical compositions and pharmaceutical formulations containing antibiotics against bacterial infections that cause Modic changes and CLBP are developed. The formulations and methods can be used to treat, prevent, ameliorate, and / or alleviate one or more of the pain and phenotypic manifestations that are associated with diseases, conditions, or disorders of bones, joints, ligaments, and / or tendons, especially when there is an association with Modic changes or bone edema caused by bacterial infection.

[0018] Types of pain may include, but are not limited to, acute pain, subacute pain, chronic or constant pain, localized pain, radicular pain, referred pain, somatic pain, radiating pain, neuropathic pain, inflammatory pain, and pain of mixed or non-specific origin. Pain may be located in various parts of the body, for example, in the limbs, muscles, skin, joints, deep tissues or organs, or spine (e.g., cervical, thoracic, lumbar, or sacral).

[0019] Phenotypic presentations (defined as any outward symptoms, whether perceived or experienced by the subject) may include, but are not limited to: pain of any kind, nocturnal sleep disturbances generally due to pain, pain during the Valsalva maneuver, pain during active lumbar flexion, pain during active lumbar extension, a positive cranial compression test, pain during a springing test, difficulty turning in bed, difficulty getting up from a chair, difficulty climbing stairs, difficulty bending or kneeling, and difficulty standing or walking for extended periods of time.

[0020] Diseases, conditions, or disorders of bones, joints, ligaments, and / or tendons that occur simultaneously with pain include, but are not limited to, Modic changes, bone edema, lumbar disc herniation, tendonitis, tendon rupture, ligament inflammation, ligament rupture, pubic symphysis separation, pelvic girdle syndrome (PHS), and others. girdle syndrome, and Scheuermann's disease.

[0021] The pain or phenotype may be (1) caused by a disease, condition, or disorder, (2) occur simultaneously with a disease, condition, or disorder, (3) present at or near the site of a disease, condition, or disorder, or (4) any combination of the above. Examples of diseases that cause low back pain (LBP) include: arthritis, diffuse idiopathic osteoarthritis (DISH or Forestier's Disease), sciatica, degenerative disc disease, lumbar spinal stenosis, spondylolisthesis, herniated disc, scoliosis, radiculopathy, joint dysfunction, coccydynia, endometriosis, and osteoporosis.

[0022] The present invention relates to linezolid compositions and formulations that deliver an effective amount of linezolid locally to a disease site or area adjacent to the site requiring treatment. Linezolid is formulated in a thermosensitive poloxamer vehicle that forms a degradable gel in response to temperature changes. This thermosensitive carrier, which is an aqueous solution at room temperature, forms a gel in situ at body temperature, releasing the loaded linezolid to the target site. The gelling properties of this formulation may avoid leakage of the active drug from the injection site, thus increasing the amount of active drug at the target site.

[0023] I. Linezolid formulations The pharmaceutical compositions and formulations of the invention comprise linezolid as an active pharmaceutical ingredient (API) in combination with one or more pharma- ceutically acceptable carriers or excipients for treating, preventing, ameliorating, or alleviating pain. The linezolid compositions and formulations of the invention may optionally comprise one or more additional active agents (e.g., therapeutically and / or prophylactically active agents). In some examples, the compositions may include at least another anti-inflammatory agent or another anti-infective agent, or the like.

[0024] Specifically, the linezolid formulations may be used to administer an antibiotic composition as discussed herein to the disease site to treat, prevent, ameliorate, or alleviate lower back pain while eliminating bacterial infections in the cervical, thoracic, lumbar, or sacral spine.

[0025] The formulations described herein may be prepared by any method known or hereafter developed in the field of pharmacology. General considerations in the formulation and / or manufacture of pharmaceutical products may be found, for example, in Remington: The Science and Practice of Pharmacy, 21st Edition, Lippincott Williams & Wilkins, 2005, the contents of which are incorporated herein by reference in their entirety. In general, such preparation methods include the steps of bringing the active ingredient into association with an excipient, diluent, and / or one or more other accessory ingredients, and then, as necessary and / or desired, dividing, shaping, and / or packaging the product into desired single- or multi-dosage units.

[0026] The pharmaceutical formulation according to the present invention can be prepared, packaged, and / or sold in bulk as one single unit dose and / or as a plurality of single unit doses. As used herein, a "unit dose" refers to a discrete amount of a pharmaceutical composition that contains a predetermined amount of active ingredient. This amount of active ingredient is generally equal to the dosage of the active ingredient that would be administered to a subject, and / or a convenient fraction of such a dosage (e.g., one-half or one-third of such a dosage).

[0027] The linezolid formulations of the invention may comprise a therapeutically effective amount of linezolid formulated in a delivery vehicle comprising a thermosensitive poloxamer hydrogel and the non-ionic contrast agent iohexol. The poloxamer and iohexol-containing delivery vehicle is an aqueous solution below 26° C. and gels at higher temperatures (e.g., temperatures approaching body temperature). Optionally, one or more pharma- ceutically acceptable excipients may also be added to the formulation. The relative amounts of the active ingredient (i.e., linezolid), pharma- ceutically acceptable excipients, and / or any additional components in a pharmaceutical composition according to the invention will vary depending on the identity, size, and / or condition of the subject being treated, as well as the route by which the composition is administered.

[0028] The formulation may be injectable. The injectable pharmaceutical composition is formulated to be injected into an anatomical structure of a subject, including, but not limited to, an intervertebral disc, an intervertebral space, an intra-articular space, a ligament, a tendon, a tendon-bone junction, a joint, an epidural space, a facet joint, a site adjacent to bone edema, or other spinal compartment. In a preferred embodiment, the injectable linezolid formulation may be used to deliver an API into an intervertebral disc and / or into the disc space. The injectable formulation includes at least one polymer that forms a solution but gels at body temperature. The thermosensitive hydrogel carries the loaded antibiotic to the injection site where it is effective against infection. The gelling formulation of the present invention may remain at the injected site long enough for the antibiotic to diffuse into the disc tissue, avoiding leakage of the antibiotic from the injected area. This feature is particularly beneficial in damaged discs, where the disc may leak quickly when the needle is withdrawn.

[0029] In some embodiments, linezolid compositions and formulations are administered to humans, human patients, or non-human subjects. For example, the formulations may be administered to patients with back pain or at risk for developing back pain. In some embodiments, the subject to whom the therapeutic composition is administered suffers from or is at risk for developing pain at or near a bone, joint, ligament, or tendon.

[0030] Active ingredient – ​​Linezolid As described in the background, chronic low back pain is often closely related to Modic change after lumbar disc herniation.Since anaerobic bacteria are often observed in the core tissue of lumbar disc herniation, the pharmaceutical composition for treating the pain associated with Modic change can comprise at least one antibiotic as the active ingredient for killing or inhibiting one or more target bacteria.

[0031] The choice of active agent may depend on the bacterial pathogen isolated from Modic disc. The most frequently isolated bacterial pathogens from Modic disc are Staphylococcus spp. and P. acnes. Antibiotic resistance varies in different populations and regions around the world. To provide a robust and broadly effective treatment, a general resistance cover including P. acnes and Staphylococcus or at a minimum only P. acnes would be preferred. Preferably, considering the resistance profile of pathogens isolated at the site of infection associated with Modic, an antibiotic effective against current clinical isolates from any site of infection may be selected as the active agent of the composition and formulation.

[0032] For example, the pharmaceutical formulations of the present invention may contain active agents for treating both Staphylococcus spp. and P. acnes, the bacterial pathogens most frequently isolated from Modic discs. In some embodiments, the pharmaceutical formulations of the present invention may contain at least one antibiotic for the treatment of P. acnes infections, which cause the majority of infections studied (about 38% of Modic Type 1 patients). Evidence from previous treatments with many potential antibacterial therapies for P. acnes and Staphylococcus spp., respectively, has identified several antibiotics that are effective against at least one of these pathogens. In the present invention, an antibiotic that is effective against both P. acnes and Staphylococci may be selected as the active agent of the present compositions and formulations. In some embodiments, antibiotic combinations may be selected that are effective against both P. acnes and Staphylococci.

[0033] In a preferred embodiment, the antibiotic is linezolid, the first clinically used oxazolidinone against most disease-causing gram-positive bacteria, such as streptococci, vancomycin-resistant enterococci (VRE), and methicillin-resistant Staphylococcus aureus (MRSA) (Gaudin et al., Eur J Clin Microbiol Infect Dis. 2013, 32(2):195-198). Linezolid has been used successfully to treat patients with endocarditis and bacteremia, osteomyelitis, bone and joint infections, and tuberculosis, and is often used to treat complicated infections when other therapies have failed (Gautier et al., JM. J Biomater Appl. 2012, 26(7):811-828; Tsiolis et al., Surg Infect (Larchmt.) 2011, 12(2):131-135). Prolonged use of linezolid (e.g., >2 weeks) can cause serious side effects (Falagas et al., Int. J Antimic Agents 2007, vol. 29(3): 233-239). Linezolid is well absorbed, with a bioavailability of approximately 100% in healthy volunteers. Linezolid can penetrate tissues relatively quickly, reaching its MIC of 4 mg / L. Linezolid can also penetrate the intervertebral disc and surrounding tissues (Komatsu et al., Eur. Spine J. 2010, vol. 19(12): 2149-2155).Higher success rates of linezolid may be obtained at AUC:MIC values ​​of 80-120 and when concentrations remain above the MIC throughout the dosing interval (reviewed by Dryden, J. Antimicrob. Chemother. 2011, 66(Suppl 4):iv7-iv15).

[0034] In the present invention, linezolid is selected as the active ingredient and formulated to deliver a pharma- tically effective amount of linezolid to a target site in a subject in need thereof. An effective amount of the composition is defined at least in part based on the target bacteria, the means of administration, and other determinants. In general, an effective amount of the composition will result in efficient killing or inhibition of the target bacteria and will reduce pain or reduce the risk of developing pain in a subject in need thereof.

[0035] In some embodiments, the effective dosage level of linezolid exceeds the minimum inhibitory concentration (MIC) of the target bacteria, which is an anaerobic bacterium, such as P. acnes, Corynebacterium propinquum, or a species of the Staphylococcus genus.

[0036] Different crystalline modifications (polymorphs) of Linezolid can be obtained by recrystallization using organic solvents under different conditions.Several polymorphic forms of Linezolid may be selected as the active ingredient of the present formulation. For example, linezolid can be linezolid Form I (e.g., U.S. Pat. No. 6,444,813), or Form II (e.g., U.S. Pat. No. 6,559,305), or Form III (e.g., U.S. Pat. No. 7,718,799; U.S. Patent Application Publication No. 2007 / 0104785), or Form IV (e.g., U.S. Patent Application Publication No. 2008 / 0319191), or other crystalline forms as described in WO 2007 / 026369, WO 2006 / 110155, and WO 2014 / 013498, and U.S. Patent Application Publication No. 2017 / 0008919, the contents of each of which are incorporated herein by reference in their entireties. As detailed in U.S. Pat. No. 6,559,305, linezolid ((S)—N-[[3-[3-fluoro-4-(4-morpholinyl)phenyl]-2-oxo-5-oxazolidinyl]methyl]acetamide) Form II may be characterized by an X-ray powder diffraction spectrum having the following peaks:

[0037] [Table 1] As detailed in U.S. Pat. No. 6,559,305, linezolid ((S)-N-[[3-[3-fluoro-4-(4-morpholinyl)phenyl]-2-oxo-5-oxazolidinyl]methyl]acetamide) Form II may be further characterized by an infrared (IR) spectrum as a mineral oil mull having the following peaks: 3364, 1748, 1675, 1537, 1517, 1445, 1410, 1401, 1358, 1329, 1287, 1274, 1253, 1237, 1221, 1145, 1130, 1123, 1116, 1078, 1066, 1049, 907, 852, and 758 cm. -1 .

[0038] In one embodiment, linezolid form II is selected as the active ingredient in the formulation. Linezolid form II can be milled into small particles and uniformly dispersed in the poloxamer solution at low or room temperature. The dispersed linezolid form II particles form a suspension in the poloxamer solution.

[0039] In the present invention, the linezolid particles may be sterilized to prepare a sterile injectable formulation. Linezolid may be sterilized by any method known in the art, such as dry heat or steam. In a preferred embodiment, the linezolid particles may be sterilized by gamma irradiation.

[0040] A companion drug (or a drug used in combination) may be administered together with the active ingredient of the present invention. In certain embodiments, an anti-inflammatory drug is also administered, for example, aspirin, ibuprofen, ketoprofen, naproxen, cefacoxib, rofecoxib, parecoxib, celecoxib, valdecoxib, and indomethacin. In certain embodiments, a pain relieving medication is also administered, for example, acetaminophen, morphine, oxycodone, and codeine. Companion drugs may also include over-the-counter pain relieving patches, pain relieving medicines, and / or pain relieving ointments.

[0041] Delivery Vehicle - Thermosensitive Hydrogel For administration to a subject in need, the active ingredient of the present invention (i.e., linezolid) may be incorporated into a delivery vehicle. The delivery vehicle may be suitable for injection. For example, the delivery vehicle may be an aqueous solution, a low viscosity solution, a suspension, or a reversible thermogel. The vehicle is preferably a biodegradable and biocompatible carrier. As used herein, the term "biocompatible" refers to a carrier that is not toxic to tissues and cells. As used herein, the terms "biodegradable" and "bioresorbable" are used interchangeably. Biodegradation or bioresorption in the context of the present invention refers to the degradation, disassembly, digestion, or disappearance of the delivery material after releasing the formulated therapeutically active ingredient in a biological environment by the action of the living body, and most notably at physiological pH and temperature. Specific reactions include, but are not limited to, chemical or enzymatic degradation.

[0042] In the present invention, the delivery of linezolid employs a thermosensitive hydrogel biomaterial, particularly an injectable thermosensitive hydrogel with a solution-gel transition temperature that is around or below physiological temperature. An aqueous suspension containing linezolid is formed at room temperature, but after in vivo injection, it can transition to a non-flowable / rigid gel at body temperature. Over the course of hours or days, this gel breaks down (i.e., is biodegradable). Varying the concentrations of components in the formulation can allow for fine tuning of properties (e.g., the temperature at which the gel occurs or the rate at which the gel breaks down).

[0043] 1. Poloxamer Thermosensitive hydrogels may be composed of synthetic polymers, natural polymers, or a combination thereof. A pharmaceutical agent (e.g., linezolid) and a suitable carrier may be mixed with the polymer solution in vitro prior to gelation, and a drug-loaded hydrogel may form in situ after in vivo administration.

[0044] In some embodiments, the thermosensitive hydrogel may be formed from synthetic polymers, which may include, but are not limited to, poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide) (PEO-PPO-PPO) triblock copolymers (also known as Poloxamers® or Pluronics®) and derivatives thereof, poly(N-isopropylacrylamide)-based (PNIPAAM) copolymers and derivatives thereof, poly(organophosphazenes), and poly(ethylene glycol) (PEG) / biodegradable polyester copolymers.

[0045] Poloxamer® or Pluronic® is a thermosensitive synthetic polymer approved by the FDA. Poloxamer is a non-ionic triblock copolymer composed of a central hydrophobic chain of polyoxypropylene (poly(propylene oxide)) flanked by two hydrophilic chains of polyoxyethylene (poly(ethylene oxide)). Biocompatible poloxamers are widely used in drug delivery and tissue engineering. Poloxamer-based hydrogels allow reversible gelation under certain physiological temperatures and pH by adjusting the composition of PEO and PPO, as well as the overall molecular weight and concentration. Poloxamers that have been used in drug delivery include, but are not limited to, Poloxamer® 188 (Pluronic® F-68, FLOCOR, or RheothRx), Poloxamer® 237 (Pluronic® F87), Poloxamer® 238 (Pluronic® F-88), Pluronic® F-98, Poloxamer® 124 (Pluronic® L-44), Poloxamer® 184 (L-64), Poloxamer® 338 (Pluronic® F-108), Poloxamer® 401 (Pluronic® L-121), and Poloxamer® 407 (Pluronic® F-127). The physicochemical characteristics and gel-forming properties of some selected poloxamers can be found in Table 1 of U.S. Pat. No. 5,702,717, the contents of which are incorporated herein by reference in their entirety.

[0046] Poloxamer® 407 (also known as Pluronic® F-127, Kolliphor 407, and Synperonic PE / F 127) is one of the least toxic block copolymers and is widely used as a drug delivery system. At a pure concentration of 20% (w / w), Poloxamer® 407 is liquid in aqueous solution at or below room temperature (about 25° C.), but forms a soft gel at body temperature (37° C.). Poloxamer® 407 is a triblock copolymer, consisting of about 70% PEO (polyethylene glycol) and 30% PPO (polypropylene oxide) by weight, with an average molecular weight of 11,500. Like other poloxamers, Poloxamer® 407 exhibits thermoreversible gelation behavior. As reviewed by Gong et al. (Curr. Med. Chem. 2013, 20:79-94, the contents of which are incorporated herein by reference in their entirety), Poloxamer® 407 has been utilized for the delivery of many drugs, proteins, and genes.

[0047] In some embodiments, the thermosensitive hydrogels may be formed from natural polymers (e.g., modified polymers that have improved thermoresponsive gelation behavior). Natural polymers that may be used to form thermosensitive hydrogels include, but are not limited to, chitosan and related derivatives, methylcellulose, alginate, hyaluronic acid, dextran, and xyloglucan.

[0048] 2. Non-ionic contrast agents – Iohexol Previous studies have shown that the controlled and sustained release of antibiotics (e.g., vancomycin and linezolid) encapsulated in poloxamers can be used to enhance the effectiveness of antibiotics in inhibiting bacterial growth (Veyries et al., Int. J. Pharm. 1999, 192(2):183-193; Veyries et al., Antimicrob Agents Chemother. 2000, 44(4):1093-1096; Kalorewicz et al., Polim. Med. 2011, 41(4):3-15; and Lee et al., J Control Release. 2011, 11, 11). Release, 2004, vol. 96(no. 1): pp. 1-7), but none of these previous studies examined the effect of the addition of other pharmaceutical agents. For example, radiopaque contrast agents are often used as guides to confirm needle tip position during injections and other painful procedures (e.g., discography). The iodine content in contrast agents such as Iohexol (trade name: Omnipaque) can block the penetration of x-rays, allowing the injection site to be visualized under fluoroscopy or x-ray. Iohexol is a triiodinated molecule with a molecular weight of 821.1 (46.3% iodine content). The most commonly available iohexol formulations, Omnipaque, vary in iodine concentration; for example, Omnipaque 140 contains 302 mg of iohexol per ml, which corresponds to 140 mg of organic iodine; Omnipaque 180 contains 388 mg of iohexol per ml, which corresponds to 180 mg of organic iodine; Omnipaque 240 contains 518 mg of iohexol per ml, which corresponds to 240 mg of organic iodine; Omnipaque 300 contains 647 mg of iohexol per ml, which corresponds to 300 mg of organic iodine; and Omnipaque 350 contains 755 mg of iohexol per ml, which corresponds to 350 mg of organic iodine.

[0049] In the present invention, the poloxamer-containing vehicle may further comprise a radio-contrast agent, such as iohexol, to facilitate application of the linezolid formulation to the target disease site (e.g., intervertebral disc). The addition of a radio-contrast agent in the antibiotic formulation may assist medical practitioners (such as physicians) in using fluoroscopy to identify the product being administered and monitor the condition of the administered intervertebral disc. This real-time information may help the practitioner determine when to stop the injection as the disc fills and begins to leak.

[0050] Experiments performed in the present invention have shown that the addition of iohexol to a linezolid formulation increases the radiographic visibility of the composition for monitoring the delivery of the linezolid formulation to disease sites (e.g., as shown in Example 2). It has also been discovered that the concentrations of iohexol and poloxamer 407 in the delivery vehicle need to be optimized to achieve the target temperature range for the solution-to-gel transition of the thermosensitive hydrogel formulation (see Example 5). The interaction of poloxamer and iohexol in the hydrogel affects the transition temperature of the linezolid formulation.

[0051] In some embodiments, a delivery vehicle containing poloxamer 407 and iohexol may be prepared as a separate solution prior to the addition of linezolid to form the present linezolid formulation (i.e., a linezolid suspension). The concentrations of poloxamer and iohexol are optimized to a certain range such that the gelling temperature of this solution is optimized at or near body temperature.

[0052] The present invention also provides a thermosensitive hydrogel for drug delivery. In some embodiments, the vehicle may include a poloxamer as a pharma- ceutically acceptable, biodegradable, and biocompatible polymer that forms a hydrogel in response to an increase in temperature. In some aspects, the delivery vehicle includes poloxamer 407 at about 10% to about 17% by weight of the delivery vehicle, or at a concentration of about 121 mg / ml to about 207 mg / ml by volume of the vehicle. Preferably, the delivery vehicle may include poloxamer 407 at about 11.5% to about 13.5% by weight of the vehicle, or at a concentration of about 140 mg / ml to about 165 mg / ml in the vehicle. In other embodiments, the delivery vehicle further includes a radiopaque dye. In some embodiments, the vehicle contains iohexol at about 14.5% to about 62.5% by weight of the vehicle, or at a concentration of about 174 mg / ml to about 755 mg / ml in the vehicle. Preferably, the delivery vehicle may contain iohexol at about 18% to about 35% by weight of the vehicle, or at a concentration of about 206 mg / ml to 425 mg / ml in the vehicle.

[0053] One of skill in the art may know that in addition to forming the linezolid suspensions of the present invention, the delivery vehicles described herein may be used to deliver any drug, such as antibiotics from the beta-lactam antibiotic class (e.g., penicillins, cephalosporins, carbapenems, and monobactams), oxazolidinones, aminoglycosides, glycopeptides, lipopeptides, and glycylcyclines.

[0054] In the present invention, a poloxamer hydrogel solution can be produced at a lower temperature by the steps of: (1) preparing a cold iohexol solution by adding iohexol to a solution containing tromethamine and calcium disodium EDTA (pH about 8.0), and (2) slowly adding poloxamer 407 powder to the cold iohexol solution and stirring the solution until the poloxamer powder is completely dissolved, where the poloxamer powder is added in portions. The poloxamer-iohexol solution can be sterilized and filled into separate vials.

[0055] Other Carriers and Additives The linezolid formulations of the present invention may further comprise one or more pharma- ceutically acceptable excipients suitable for the particular form of administration desired. Various excipients for formulating pharmaceutical compositions and techniques for preparing said compositions are known in the art (see Remington: The Science and Practice of Pharmacy, 21st ed., A.R. Gennaro, Lippincott, Williams & Wilkins, Baltimore, MD, 2006, incorporated herein by reference). The use of any conventional excipient vehicle may be contemplated within the scope of the present disclosure, except insofar as the conventional excipient vehicle may be incompatible with the substance or derivatives of this substance, for example, by producing any undesirable biological effects or by otherwise adversely interacting with any other components of the pharmaceutical composition.

[0056] In some embodiments, the pharma- ceutically acceptable excipient may be at least 95% pure, at least 96% pure, at least 97% pure, at least 98% pure, at least 99% pure, or 100% pure. In some embodiments, the excipient may be approved for human and veterinary use. In some embodiments, the excipient may be approved by the U.S. Food and Drug Administration. In some embodiments, the excipient may be pharmaceutical grade. In some embodiments, the excipient may meet the standards of the United States Pharmacopoeia (USP), the European Pharmacopoeia (EP), the British Pharmacopoeia, and / or the International Pharmacopoeia.

[0057] In some embodiments, the formulations of the present invention may further comprise a chelating agent and a buffering agent. Exemplary chelating agents include: ethylenediaminetetraacetic acid (EDTA), citric acid monohydrate, edetate disodium, edetate calcium disodium, edetate dipotassium, edetate, fumaric acid, malic acid, phosphoric acid, edetate sodium, tartaric acid, and / or edetate trisodium. In one example, the agent may be a salt of EDTA.

[0058] Exemplary buffering agents include, but are not limited to, citrate buffer, acetate buffer, phosphate buffer, ammonium chloride, calcium carbonate, calcium chloride, calcium citrate, calcium glubionate, calcium gluceptate, calcium gluconate, d-gluconic acid, calcium glycerophosphate, calcium lactate, propanoic acid, calcium levulinate, pentanoic acid, calcium hydrogen phosphate, phosphoric acid, tricalcium phosphate, calcium hydroxide phosphate, potassium acetate, potassium chloride, potassium gluconate, potassium mixture, potassium monohydrogen phosphate, potassium dihydrogen phosphate, potassium phosphate mixture, sodium acetate, sodium bicarbonate, sodium chloride, sodium citrate, sodium lactate, sodium hydrogen phosphate, sodium dihydrogen phosphate, sodium phosphate mixture, tromethamine, magnesium hydroxide, aluminum hydroxide, alginic acid, pyrogen-free water, isotonic saline, Ringer's solution, ethyl alcohol, and the like, and / or combinations thereof. In one embodiment, the buffering agent can be tromethamine.

[0059] Linezolid formulations The linezolid formulations of the present invention comprise a thermosensitive poloxamer hydrogel loaded with an effective amount of linezolid, the non-ionic contrast agent iohexol at a concentration suitable for transition from the poloxamer solution to a gel, and optionally one or more pharma- ceutically acceptable excipients.

[0060] In some embodiments, linezolid may be prepared as a suspension in a delivery vehicle comprising poloxamer and iohexol. In one preferred embodiment, the API (i.e., linezolid) is linezolid Form II, which is milled to form small particles, sterilized by gamma irradiation, and forms a suspension in the poloxamer-iohexol vehicle.

[0061] In some embodiments, the formulations of the invention contain linezolid at a concentration ranging from about 1% to about 50% by weight or volume of the composition (i.e., a linezolid suspension). In some aspects, linezolid can be present at about 1% to about 20%, or about 2.5% to about 20%, or about 2.5% to about 10%, or about 3.0% to about 10% by weight or volume of the composition. In one aspect, the linezolid formulation can contain about 2.5%, 5%, 7.5%, 10%, 12.5%, 15%, 17.5%, or 20% linezolid by weight of the final composition (e.g., suspension). Linezolid can be present in the formulation at a concentration of about 10 mg / ml to about 200 mg / ml, or about 20 mg / ml to about 200 mg / ml, or about 50 mg / ml to about 200 mg / ml. Specifically, linezolid may be present in the formulation at a concentration of 10mg / ml, 25mg / ml, 30mg / ml, 35mg / ml, 40mg / ml, 45mg / ml, 50mg / ml, 55mg / ml, 60mg / ml, 65mg / ml, 70mg / ml, 75mg / ml, 80mg / ml, 85mg / ml, 90mg / ml, 100mg / ml, 150mg / ml, or 200mg / ml.

[0062] In some embodiments, the formulations of the invention include a poloxamer as a pharma- ceutically acceptable, biodegradable, biocompatible polymer that forms a hydrogel in response to an increase in temperature. In some aspects, the poloxamer is poloxamer 407. The linezolid formulations of the invention may include poloxamer 407 at about 9.5% to about 17% by weight of the formulation, or at about 9.5% to about 14.5% by weight of the formulation, or at a concentration of about 115 mg / ml to about 207 mg / ml, or at a concentration of about 115 mg / ml to about 173 mg / ml in the formulation. Preferably, the linezolid formulations may include poloxamer 407 at about 10.8% to about 12.8% by weight of the formulation, or at a concentration of about 130 mg / ml to 156 mg / ml in the formulation.

[0063] The pharmaceutical preparation of the present invention further comprises a non-ionic contrast agent. For example, the pharmaceutical preparation of the present invention may comprise about 30 mg to about 600 mg of iodine per milliliter of the pharmaceutical solution, and preferably about 50 mg to about 300 mg or about 75 mg to about 200 mg of iodine per milliliter of the pharmaceutical solution.

[0064] In some embodiments, the agent is iohexol. The pharmaceutical composition may contain iohexol at about 14% to about 59% by weight of the formulation, or at a concentration of about 165 mg / ml to about 718 mg / ml in the formulation. Preferably, the linezolid formulation may contain iohexol at about 17% to about 30% by weight of the formulation, or at a concentration of about 206 mg / ml to 364 mg / ml in the formulation.

[0065] In some embodiments within the scope of the present invention, other surfactants, solvents, or co-solvents known to those of skill in the art may also be used. In some embodiments, the linezolid formulations of the invention contain about 1% to about 20% linezolid (w / w) by weight of the formulation, about 9.5% to about 17% poloxamer 407 (w / w) by weight of the formulation, and about 14% to 59% iohexol (w / w) by weight of the formulation. In a preferred embodiment, the linezolid formulation contains about 5% w / w linezolid, about 11.8% w / w poloxamer, and about 27.2% w / w iohexol. In some examples, the aqueous formulations may gel at about 26°C, or about 27°C, or about 28°C, or about 30°C, or about 31°C, or about 32°C, or about 33°C, or about 34°C, or about 35°C, or about 36°C, or about 37°C. In one non-limiting example, the linezolid formulation gels at about 28° C. Linezolid may diffuse out of the rigid gel. Over the course of several days, the gel degrades. Varying the concentrations of components in the formulation (e.g., iohexol and poloxamer 407) may allow for fine tuning of the gel's properties, such as the solution-to-gel transition temperature.

[0066] In some embodiments, the formulation may be prepared by a process comprising the steps of: (a) milling linezolid form II powder to form small linezolid particles; (b) preparing units of linezolid particles of step (a) and sterilizing the preparation; (c) preparing a delivery vehicle comprising poloxamer 407 and iohexol; and (d) suspending the linezolid particles of step (b) in the delivery vehicle of step (c) to form a stable, homogenous suspension.

[0067] Poloxamer, which is a thermal gel, can be dissolved in an appropriate amount of aqueous solution at low temperature, and the concentrations of poloxamer and iohexol are optimized in terms of the gelling properties of the delivery vehicle. Linezolid (especially linezolid form II) may be milled to form small particles using dry air jet milling or any other milling approach. The resulting linezolid powder may be further sterilized by dry heating and / or gamma irradiation.

[0068] In some embodiments, the linezolid particles and the poloxamer / iohexol delivery vehicle may be prepared and filled separately, for example, into two separate vials. Prior to administration, the two preparations may be mixed to form a linezolid suspension. Prior to application, the linezolid powder and vehicle are mixed to form a homogenous suspension. The antibiotic suspension is drawn into a syringe and prepared at the intended dose. In one example, about 253 mg of linezolid powder may be placed in a vial, and about 7 ml of the delivery vehicle containing poloxamer and iohexol may be prepared in another vial. The delivery vehicle may be placed in a volume of about 3.8 ml to about 5.8 ml or about 4.6 ml to about 5.0 ml.

[0069] Injectable formulations may be sterilized, for example, by filtration through a bacteria-retaining filter, by irradiation, by steam sterilization, and / or by incorporating sterilizing agents in the form of sterile solid compositions which can be dissolved or dispersed in sterile water or other sterile injectable medium prior to use.

[0070] In some embodiments, the thermosensitive hydrogel formulation of the present invention can be administered to the disease site using a needle. The water solubility of the thermogel at room temperature and the relatively low viscosity of the aqueous solution allow the use of a small diameter needle. Such an injectable formulation can be effectively administered to a patient through a small needle size without prior gelation.

[0071] II. Administration and Dosing The linezolid compositions of the present invention may be administered by any route that provides a therapeutically effective outcome. In a preferred embodiment, the formulation is suitable for injection. Injection administration that provides local effective levels of linezolid (above the MIC of the target bacteria) has a beneficial outcome (e.g., pain relief).

[0072] Injectable administration would reduce the level of systemic side effects, increase patient compliance with the dosing regimen, and increase efficacy at the site of action with lower antibiotic doses. Advantages may include relatively easy application, localized delivery of site-specific action within the body, reduced dosing frequency without compromising efficacy of treatment, increased compliance, etc.

[0073] Pharmaceutical compositions according to the present invention are generally formulated in dosage unit form for ease of administration and uniformity of dosage. It will be understood, however, that the dosage of the pharmaceutical compositions of the present invention will be decided by the attending physician within the scope of sound medical judgment.

[0074] In the present invention, the pharmaceutical formulation may be administered at a dosage level sufficient to deliver a total dose of 5 mg to 450 mg of linezolid to the intervertebral disc to obtain the desired therapeutic effect. In some embodiments, the composition may deliver about 50 mg to about 200 mg of linezolid to obtain the desired therapeutic effect. In some embodiments, the total dose is about 10 mg to about 100 mg of linezolid, or about 10 mg to about 200 mg of linezolid, or about 20 mg to about 200 mg of linezolid, or about 50 mg to about 200 mg of linezolid. In some examples, the formulation may deliver a total dose of 50 mg, 60 mg, 70 mg, 80 mg, 90 mg, 100 mg, 110 mg, 120 mg, 130 mg, 140 mg, 150 mg, 160 mg, 170 mg, 180 mg, 190 mg, or 200 mg of linezolid. In some embodiments, the dosage level is determined based on the number of infected discs. For example, the dosage can be in the range of 5mg to 450mg for each infected disc, for example, 5mg for each infected disc, or 10mg for each infected disc, or 15mg for each infected disc, or 20mg for each infected disc, or 50mg for each infected disc, or 100mg for each infected disc, or 150mg for each infected disc, or 200mg for each infected disc, or 250mg for each infected disc, or 300mg for each infected disc, or 350mg for each infected disc, or 400mg for each infected disc, or 450mg for each infected disc. In one preferred embodiment, the effective amount of linezolid is from about 50 mg to about 200 mg for each infected disc.

[0075] As a non-limiting example, to achieve the expected total dose of linezolid for each infected disc, the linezolid suspension may be administered in a volume range ranging from about 0.1 ml to about 4.0 ml, e.g., 0.1 ml, or 0.3 ml, or 0.5 ml, or 1.0 ml, or 1.2 ml, or 1.5 ml, or 2.0 ml, or 2.5 ml, or 3.0 ml, or 3.5 ml, or 4.0 ml, or 4.5 ml, or 5.0 ml.

[0076] In some embodiments, a single dose (e.g., a single injection) is used to deliver the desired dose of linezolid to the infected disc. In other embodiments, multiple doses can be used to achieve the desired therapeutic effect. As non-limiting examples, a second dose, and perhaps a third dose, is administered 2 days, or 5 days, or 10 days, or 2 weeks, or 3 weeks, or 1 month after the previous dose.

[0077] In some embodiments, the formulations of the invention may be administered to a subject in need thereof by a single injection or by multiple injections at multiple sites at or near bones, joints, ligaments, and tendons. For example, multiple vertebral discs on the same side of the spine or on both sides of the spine may be administered. In another example, the intervertebral disc and vertebral disc space may be injected with the formulations and compositions of the present invention.

[0078] III. Kits, Needles, and Devices The invention also provides kits comprising the linezolid formulations of the invention, in some embodiments, the kits may include one or more dose units of linezolid powder and a hydrogel vehicle comprising poloxamer and iohexol, which may be mixed to form a linezolid suspension for use.

[0079] Methods and devices known in the art for multiple administration to cells, organs, and tissues are contemplated for use with the methods and compositions disclosed herein as embodiments of the present invention, including, for example, methods and devices having multiple needles, hybrid devices utilizing, for example, lumens or catheters, and devices using mechanisms powered by heat, current, or radiation.

[0080] The administration device may be utilized to deliver pharmaceutical compositions comprising at least one antibiotic of the present invention according to the single dose, multiple dose, or split dose regimens taught herein. In accordance with the present invention, the multiple dose device may be used to deliver single, multiple, or split doses of antibiotics carried in the formulations contemplated herein.

[0081] In some embodiments, a device for delivery of a drug has been described by Mckay et al. and is taught for example in International Publication WO 2006 / 118804, the contents of which are incorporated herein by reference in their entirety. According to Mckay, the device incorporates multiple needles with multiple orifices in each needle to facilitate localized delivery to tissue, such as the interior disc space of a spinal disc.

[0082] A syringe using a needle may be utilized to administer the pharmaceutical formulation of the present invention. In some cases, the tip of the needle may be specialized for a particular injection purpose, such as spinal injection. A syringe for spinal injection may have a needle that is placed into a structure or space in the spine. The needle may have any type of bevel from Quincke Babcock, Sprotte, Whitacre, Greene, Pitkin, and Tuohy. The needle shaft may be straight or curved, and may be of a particular length suitable for placing the drug at a particular location in the spine. For example, the syringe and needle may be designed as disclosed in U.S. Patent Nos. 5,628,734; 6,500,153; 7,367,961; and 8,112,159, the contents of each of which are incorporated herein by reference in their entirety.

[0083] In some embodiments, syringes and needles for administration of the pharmaceutical formulations of the present invention may include special structures configured to mix the components of the pharmaceutical formulation in situ. The syringe may include one, two, or more separate chambers in which the components of the pharmaceutical formulation are housed separately and mixed immediately prior to injection.

[0084] definition Active Pharmaceutical Ingredient (API): As used herein, the term "active pharmaceutical ingredient (API)" refers to a biologically active pharmaceutical agent. For example, a substance that, when administered to an organism, has a biological effect on the organism is considered to be biologically active. In the present invention, the API is linezolid.

[0085] Biocompatible: As used herein, the term "biocompatible" means compatibility with living cells, tissues, organs, or systems that poses little or no risk of injury, toxicity, or rejection by the immune system.

[0086] Biodegradable: As used herein, the term "biodegradable" means capable of being broken down into harmless products by the action of living organisms. Formulation: As used herein, a "formulation" comprises at least an active ingredient and a delivery agent.

[0087] Hydrogel: As used herein, the term "hydrogel" refers to a water-insoluble, crosslinked, three-dimensional network of polymer chains and water filling the voids between the polymer chains. Crosslinks promote water insolubility and provide the necessary mechanical strength and physical integrity. Hydrogels are mostly water (the mass fraction of water is much higher than the mass fraction of the polymer). The ability of hydrogels to retain significant amounts of water means that the polymer chains must have at least moderate hydrophilicity.

[0088] Patient: As used herein, the term "patient" refers to a subject who may be seeking or needing treatment, who is seeking treatment, who is undergoing treatment, who is going to undergo treatment, or who is receiving care from a trained professional for a particular disease or condition.

[0089] Pharmaceutical composition: As used herein, the phrase "pharmaceutical composition" refers to a composition that alters the pathology of a disease, disorder, and / or condition. Pharmaceutically acceptable: As used herein, the phrase "pharmacologically acceptable" is used herein to refer to compounds, substances, compositions, and / or dosage forms that are suitable for use in contact with the tissues of human beings and animals, within the scope of sound medical judgment, without excessive toxicity, irritation, allergic response, or other problem or complication, commensurate with a reasonable benefit / risk ratio.

[0090] Pharmaceutically acceptable excipient: As used herein, the phrase "pharmaceutical acceptable excipient" refers to any ingredient other than the compounds described herein and that has substantially non-toxic and non-inflammatory properties in a patient (e.g., a vehicle in which an active compound can be suspended or dissolved).

[0091] Site: As used herein, the term "site" when used in reference to bone edema or Modic changes means the site of the bone edema or Modic changes itself, or the circumference of the bone edema in all directions from 0.5 to 1 inch.

[0092] Split dose: As used herein, a "split dose" refers to a single unit dose or the division of a total treatment dose into two or more doses. Therapeutically effective amount: As used herein, the term "therapeutically effective amount" means an amount of an agent (e.g., an antibiotic, drug, therapeutic agent, diagnostic agent, prophylactic agent, etc.) delivered that, when administered to a subject suffering from or susceptible to a disease, disorder, and / or condition, is sufficient to treat, ameliorate the symptoms of, diagnose, prevent, and / or delay the onset of the disease, disorder, and / or condition.

[0093] Therapeutically Effective Outcome: As used herein, a "therapeutically effective amount" means an amount of an agent (e.g., an antibiotic, drug, therapeutic agent, diagnostic agent, prophylactic agent, etc.) delivered that, when administered to a subject suffering from or susceptible to a disease, disorder, and / or condition, is sufficient to treat, ameliorate the symptoms of, diagnose, prevent, and / or delay the onset of the disease, disorder, and / or condition.

[0094] Total treatment dose: As used herein, a "total treatment dose" refers to the amount administered or prescribed during the treatment period. The total treatment dose may be administered as a single unit dose. Treat: As used herein, the term "treat" refers to partially or completely alleviating, ameliorating, relieving, delaying the onset of, inhibiting the progression of, reducing the severity of, and / or reducing the incidence of one or more symptoms or characteristics of a particular disease, disorder, and / or condition. Treatment may be administered to subjects who do not show signs of the disease, disorder, and / or condition and / or to subjects who show only early signs of the disease, disorder, and / or condition, for the purpose of reducing the risk of developing pathology associated with the disease, disorder, and / or condition.

[0095] Vehicle: As used herein, the terms "vehicle" and "delivery vehicle" are used interchangeably and refer to any agent, compound, or combination thereof that can be used to carry an active ingredient (e.g., an API of the present invention) and deliver the active ingredient to a designated site.

[0096] Equivalence and Scope Those skilled in the art will recognize, or be able to ascertain using no more than routine experimentation, many equivalents to the specific embodiments in accordance with the invention described herein. The scope of the invention is not intended to be limited to the above Description, but rather is as set forth in the appended claims.

[0097] In the claims, articles such as "a," "an," and "the" may mean one or more, unless indicated to the contrary or otherwise clear from the context. A claim or description containing "or" between one or more members of a group is considered to be satisfied if one, more than one, or all of the members of the group are present in, employed in, or otherwise relevant to a given product or process, unless indicated to the contrary or otherwise clear from the context. The invention includes embodiments in which exactly one member of a group is present in, employed in, or otherwise relevant to a given product or process. The invention includes embodiments in which multiple members or members of an entire group are present in, employed in, or otherwise relevant to a given product or process.

[0098] It should also be noted that the term "comprising" is intended to be open, permitting but not requiring the inclusion of additional components or steps. When the term "comprising" is used herein, the term "consisting of" is also included and disclosed.

[0099] When ranges are given, the endpoints are included. Furthermore, unless otherwise indicated or otherwise clear from the context and the understanding of one of ordinary skill in the art, values ​​expressed as ranges should be understood to contemplate any particular value or subrange within the range set forth in the various embodiments of the invention, down to the tenth of the unit of the lower limit of that range, unless the context clearly dictates otherwise.

[0100] In addition, it should be understood that any particular embodiment of the present invention that falls within the prior art may be expressly excluded from any one or more of the present claims. Such embodiments may be excluded even if the exclusion is not expressly set forth herein, since they are deemed to be known to those of ordinary skill in the art. Any particular embodiment of the composition of the present invention (e.g., any constituent, therapeutic or active ingredient; any method of manufacture; any method of use, etc.) may be excluded from any one or more claims for any reason, regardless of the existence of prior art.

[0101] It is to be understood that the words which have been used are words of description rather than of limitation, and that changes may be made within the purview of the appended claims without departing from the true scope and spirit of the invention in its broader aspects.

[0102] While the invention has been described at some length and with some particularity in terms of certain illustrated embodiments, it is not intended that the invention should be limited to any such particularity or embodiment, or to any particular embodiment, but rather should be construed with reference to the appended claims so as to provide the broadest possible interpretation of such claims in view of the prior art, and thus effectively encompass the intended scope of the invention.

[0103] (Example) Example 1: Sheep model of S. aureus intradiscal infection To test the in vivo efficacy of antibiotic preparations, an ovine model of S. aureus intradiscal infection was developed. Male Charollais or Suffolk cross sheep (approximately 35-40 kg at the start of the study) were housed in accordance with Home Office guidelines under the Animals (Scientific Procedures) Act 1986 and acclimated for at least 7 days with straw bedding and access to water. The sheep were fed a sheep concentrate diet with no antibiotics added, with additional forage (hay / straw).

[0104] 1.1 Staphylococcus aureus infection 2×10 4 Dilution to CFU / ml yielded 2.5 × 10 6 Bacterial inocula (ATCC 29213) were prepared from frozen glycerol / phosphate-buffered saline stocks at CFU / ml.

[0105] 1.2 Preparation of injectable formulations Using an 18G 1 inch or 1.5 inch needle, 0.2 ml of S. aureus suspension or test formulation was aspirated into 1 ml of syrup. If necessary, the syringe may be pulled back and forth to remove air bubbles. The needle was then replaced with a 25G 4.69 inch dosing needle and primed with 0.05 ml or 0.1 ml of the dose remaining. If not used immediately, the primed syringe was placed in the refrigerator, but should be used within 30 minutes.

[0106] In the treatment model, each sheep was anesthetized. As part of the anesthesia, the animals were administered analgesia in the form of meloxicam at the recommended dosage (intramuscularly). This analgesia may be repeated if deemed necessary by the designated veterinarian. Each sheep was administered one injection per disc of S. aureus inoculum (1 x 10 3Four 0.05 ml (target volume) of 10 cells / disc were injected intradiscally at L1 / L2, L2 / L3, L3 / L4, and L4 / L5.

[0107] Approximately 1 hour after the first injection, or at another selected time, each sheep received a second injection of the linezolid or control formulation. An intradiscal injection of 0.1 ml (target volume) was administered to each disc that had already been successfully injected with bacteria. The time between administration of antibiotic and bacteria could be hours, days, weeks, or months.

[0108] 1.3 Injection Technique: Therapeutic Administration. Colocalized administration A single 20G 3.5 inch spinal needle was placed directly at the edge of the nucleus pulposus of each disc. After confirmation of needle positioning, a second 25G 4.69 inch needle primed with dose solution was inserted into the first needle and placed with the tip in the center of the nucleus pulposus. After confirmation of the positioning of the second needle, bacteria were injected into each disc. The inner needle was then removed. Just prior to the 1 hour time point after administration of bacteria, a new 25G 4.69 inch needle primed with dose solution was inserted into the 20G 3.5 inch and placed in the center of the nucleus pulposus. A second treatment dose was administered through this needle 1 hour after the first dose.

[0109] Discreet dosing Bacterial Infection: A single 20G 3.5 inch spinal needle was placed directly at the edge of the nucleus pulposus of each disc. After confirmation of needle positioning, a second 4.69 inch 25G needle primed with dose solution was inserted into the first needle, placing the tip in the center of the nucleus pulposus. After confirmation of the positioning of the second needle, bacteria were injected into each disc. The needle was then removed. The animal was repositioned to access the opposite side of the spine.

[0110] Injection of formulation: A second 30G 3.5 inch spinal needle was placed directly into the edge of the nucleus pulposus opposite the first injection in each disc. Just prior to the time of administration, a new 25G 4.69 inch needle primed with dose solution was inserted into the 20G 3.5 inch and placed in the center of the nucleus pulposus. The second treatment dose was administered through this needle.

[0111] For each injection, each dosing syringe was weighed and the weight recorded before and after dosing to calculate the actual dose administered. For each formulation, administer the dose slowly, which should take 30-60 seconds to deliver, using enough force to successfully deliver the dose without leaking any dose solution at the syringe / needle junction.

[0112] A digital x-ray imaging system was used to assist the injection and image records were kept immediately before and after administration. Animals were continuously monitored and, when fully recovered, were returned to their cages.

[0113] 1.4 Digital X-Ray Imaging Each sheep was photographed immediately before and after each administration and images were stored. Details of the sequence were recorded. Visual evaluation of each IVD injection was performed by a qualified individual immediately after administration. Injections were scored / recorded as one of the following:

[0114] Good with no leakage: well separated dose visible within the disc and no dose visible outside the disc. Minimal leakage: A well separated dose is seen within the disc and a minimal dose is seen outside the disc.

[0115] Moderate leakage: reduced dose visible within the disc, with clearly visible dose outside the disc. Extensive leakage: A minimal dose is visible within the disc, with the majority of the media clearly visible outside the disc.

[0116] To ensure the scientific robustness of this study, ideally, four treated discs / group are needed, with a minimum of three / group. After sheep injections are completed, the scores are reviewed. If the total number of discs scored as "good with no leakage" or "minimal leakage" is less than the ideal number, the addition of additional sheep to the group, up to a maximum of two sheep, will be considered.

[0117] 1.5 Tissue samples At set times after administration, the sheep are sacrificed. The discs are dissected and the nucleus pulposus is removed from each disc. In addition, an extra untreated disc is sampled to provide a control tissue. This untreated disc is removed after all of the treated discs for a particular animal, with care taken to ensure there is no contamination between the control and treated samples.

[0118] 1.6 Linezolid Extraction Extraction of linezolid from the disc samples was achieved by the addition of 3 ml of phosphate buffered saline (PBS) to the pre-weighed disc samples. The mixture was homogenized using an Omni-Prep Bead Ruptor at 4°C. An additional 3.5 ml of PBS was added, the sample was homogenized by hand, and finally another 3.5 ml of PBS was added and mixed thoroughly to give a total volume of 10 ml of PBS disc mixture. A representative aliquot of this disc homogenate containing linezolid was diluted with disc homogenate from an untreated disc to ensure that the sample was within the calibration range of the assay. Samples were extracted by protein precipitation with 3 volumes of acetonitrile acidified with 0.1 ml of formic acid and containing tolbutamide and labetalol as internal standards (50 and 25 ng / ml).

[0119] After vortex mixing and centrifugation at 4°C, the supernatant was mixed with acetonitrile:water (1:1 vol / vol) acidified with 0.1% formic acid in a shallow-well 96-well plate. The plate was sealed and shaken to ensure homogeneity prior to analysis. Samples were analyzed for linezolid by positive electrospray LC-MS / MS using a Waters TQS mass spectrometer (conditions below) against a series of matrix-matched calibration and quality control standards. Standards were prepared by mixing aliquots of diluted disc homogenates from untreated discs with linezolid and extraction as described above.

[0120] [Table 2-1]

[0121] [Table 2-2] Pharmacokinetic analysis was performed with Phoenix WinNonL software version 6.4 using the mean animal data of four discs from each animal, noncompartmental analysis and uniform weighting, the nominal time points, and the actual amount of linezolid administered to the disc. Data points were excluded from this pharmacokinetic analysis if dosing was considered subnominal (e.g., extensive leakage was observed).

[0122] 1.7 Extraction and enumeration of S. aureus from sheep intervertebral discs Each disc nucleus was placed in a 7 mL plastic Precellys bead beater tube or a 6 mL plastic Sterilin bijoux containing 2 mL of sterile phosphate buffered saline (PBS). Each disc nucleus was homogenized twice to the extent achievable in a Precellys 24BB bead beater at 6500 rpm for 45 seconds with a 30 second rest period between each homogenization step. Samples (approximately 100 μL) were removed and serially diluted 10-fold in sterile PBS before being analyzed by the diffusion method or the Miles and Misra method. Viable numbers of S. aureus (ATCC 29213) were determined by incubating MSA plates at 37°C in ambient air for approximately 16 hours.

[0123] Example 2: Methods for assessing the stability of Linezolid in pharmaceutical formulations Ultra Performance Liquid Chromatography (UPLC) was used to assay the amount and stability of linezolid in the drug product preparation. The analysis was performed on a Waters Acquity system equipped with a diode array detector and a single quad mass spectrometer using MassLynx software. The details of the method are listed in Table 2 below.

[0124] [Table 3] Example 3: Method for Analyzing the Amount of Iohexol in a Pharmaceutical Preparation HPLC was used to estimate the purity and quantity of iohexol in the formulation preparations, details of the method used are listed in Table 3 below.

[0125] [Table 4] Example 4: Preparation of Linezolid Suspension 4.1. Air-Jet Milling of Linezolid Form II and Form III To assess the ability to develop linezolid suspensions with linezolid loadings of 50 and 200 mg / mL, the short-term physical stability of the formulations (e.g., particle size, polydispersity, and uniformity) was evaluated. Different concentrations of poloxamer 407 were then added and the sol-gel transition temperature and injectability / syringeability of the suspensions were evaluated.

[0126] Different crystalline forms of linezolid were selected and tested for their suspension feasibility. Two crystalline modifications (polymorphs) of linezolid: Form II (FII) and Form III (FIII) were obtained from Symed labs Ltd (India). Approximately 1 g each of FII and FIII were jet milled using a LaboMill jet miller (FPSFood and Pharma Systems srl, Italy) at a jet line pressure of 6.91 atm (7 bar) and grind line pressure of 3.95 atm (4 bar). Particle size distribution of the raw material and the air jet milled product was analyzed by laser diffraction (Sympatec GmbH, Helos Disperse). 5 mg of each sample was placed in a dry powder disperser (RODOS / M). After a baseline measurement, each sample was run for 5 seconds at an optical density of 2%. Results were obtained at a pressure of 2.96 atm (3 bar) using lenses, R1 (0.18-0.35 μm), and R2 (0.25 / 0.45-87.5 μm) (Table 4). Data was collected using a HELOS sensor and analyzed using Windox5 software.

[0127] [Table 5] X after crushing 90 The particle size distribution was similar for both forms of linezolid.

[0128] 4.2. Suspension of Milled Linezolid Form II and Form III 50 mg of each form was weighed and 1 mL of poloxamer vehicle was added. The particles were resuspended by shaking by hand for 1 minute. The air-jet milled particles of Form II were uniformly dispersed. Form III particles formed clumps and were not uniformly dispersed. This observation indicates that linezolid Form II was preferred over Form III due to its improved suspension properties.

[0129] 4.3. Scale-Up Milling and Particle Size Distribution of Linezolid Form II Linezolid Form II (Symed, India) was air-jet milled at 0.5 kg scale to obtain micronized Linezolid Form II for formulation development. Micronization was achieved using the following method as shown in Table 5.

[0130] [Table 6] The particle size was analyzed as shown in FIG.

[0131] 4.4. API (Active Pharmaceutical Ingredient): Sterilization of Linezolid Form II Sterilization of the milled powder may be achieved by dry heat sterilization or gamma irradiation.A sterilization feasibility study was performed using glass vials containing 200 mg of milled linezolid form II.

[0132] dry heat Vials containing micronized linezolid 200 mg or spordex discs (AF0558: Steris Life Sciences, UK) were incubated at 120°C to 160°C for 2 to 50 hours as shown in Table 6. At each temperature point, the appearance and chemical stability (method of Example 2) of the linezolid form II powder was assessed. Spore discs were incubated at 30-35°C for 7 days and growth recorded.

[0133] [Table 7] Sporadex disks stored at 2-8 °C served as positive controls for bacterial growth observed after 1 day of incubation.

[0134] All dry heat conditions tested sterilized the spore disks, indicating that the bioburden was >10 6 The results show that a reduction in the percentage of linezolid present was achieved. With the exception of the 140°C treatment for 8 hours, heating linezolid powder above 120°C caused a physical change from powder to a viscous yellow liquid and a significant reduction in the percentage of linezolid present. The instability at temperatures above 130°C suggests that dry heat sterilization around 120°C may be feasible but would be technically challenging in a scaled-up process as small temperature fluctuations could lead to temperature increases and instability. Sterilization using relatively low temperatures for extended periods of time requires extensive validation and deviates from standard pharmacopoeial recommendations for dry heat sterilization.

[0135] Gamma irradiation Vials containing 200 mg micronized linezolid were filled in air or under nitrogen and subjected to gamma irradiation at 15 KGy or 25 KGy at ambient temperature or at reduced temperature by wrapping in ice. Appearance and chemical stability (method of Example 2) were evaluated at time zero from irradiation, and longer term stability was also evaluated after 28 days of storage at 25° C. or 40° C. (Table 7).

[0136] [Table 8] No visible changes in the physical appearance or color of the powder were observed after irradiation under any condition. Chemical stability 28 days after irradiation was good and as expected. There was no indication that the powder had to be vialed under nitrogen or that the samples had to be cooled during irradiation.

[0137] Gamma irradiation appeared to provide a robust sterilization method that was within pharmacopoeia guidelines. The data also suggest that gamma irradiation does not affect the stability of linezolid. Gamma irradiation is the preferred method for sterilization of milled linezolid Form II powder in vials.

[0138] Example 5: Optimization of delivery vehicles: Poloxamer-based gel vehicles 5.1 Preparation of poloxamer hydrogel A general procedure is followed to prepare the poloxamer vehicle for linezolid injection. A modified low-temperature method from that described in the art (Schmolka, Journal of Biomedical Materials Research, 1972, vol. 6(no. 6): pp. 571-582) is used to form the poloxamer hydrogel. Tromethamine pH buffer, chelating agent calcium disodium EDTA, and radiopaque iohexol are first composed in water, and then poloxamer 407 is added. The mixture is left in the cold until the poloxamer hydrates to a clear solution. The injection vehicle is composed on a weight by weight basis. The procedure is repeated to optimize conditions until a suitable formulation is determined. Weights and volumes are used to set the target concentrations and ranges of tromethamine, EDTA, and iohexol in the final linezolid injection suspension.

[0139] 5.2. Sol-gel temperature of poloxamer hydrogels with the addition of iohexol In one study, three vehicles were prepared starting with various concentrations of iodine provided by iohexol: V150, V170, and V190, and the same concentrations of tromethamine and CaNa2EDTA. Each vehicle was split into two, and poloxamer 407 was added at a concentration of 12% weight / weight (% w / w) or 12.5% ​​w / w, respectively. The volumes of the 12% w / w and 12.5% ​​w / w poloxamer vehicles, and therefore their densities, were slightly different. Sol-gels of six formulations were evaluated to evaluate the effect of iodine (iohexol) concentration and poloxamer concentration. The samples were warmed from room temperature to 40°C in 2°C intervals and classified according to their rheological properties by inverting the vial and assessing them as liquids (L) if they moved rapidly in the direction of gravity, viscous liquids (VL) and VVL if they moved slowly downward in the direction of gravity, and gels (G) if they remained at the bottom of the vial, the latter of which was classified as the sol-gel transition temperature (Table 8).

[0140] [Table 9] Osmolarity increases with increasing iohexol and poloxamer content. Similarly, density increases with increasing iohexol concentration. However, the densities of 12% w / w poloxamer and 12.5% ​​w / w poloxamer in the same vehicle are similar (Table 8).

[0141] With starting concentrations of 150 mg I / ml or 170 mg I / ml, 12.5% ​​w / w poloxamer 407 achieved target solution gelation temperatures of 32-34° C. for the vehicle. However, at 190 mg I / ml, the vehicle gelled at 36° C. with 12.0% w / w poloxamer 407 and at 28° C. with 12.5% ​​w / w poloxamer 407, suggesting that the optimal poloxamer 407 concentration would be between 12.0% and 12.5% ​​w / w for the 190 mg I / ml vehicle.

[0142] 5.3 Development of Linezolid Poloxamer Formulation Linezolid micronized powder prepared as described in Example 4 was mixed with the poloxamer solution immediately prior to administration. The target final concentration of linezolid at the time of injection is set at 50 mg / ml. A linezolid concentration of 50 mg / ml can be achieved by resuspending approximately 200 mg of linezolid powder in approximately 3.8 ml of poloxamer vehicle to give a final volume of approximately 4.0 ml. Other amounts of linezolid and poloxamer vehicle (e.g., 100 mg linezolid and 1.9 ml poloxamer vehicle) could achieve the same concentration.

[0143] 5.4 Preparation Procedure Another study was conducted to test the addition of an API (linezolid) to the poloxamer vehicle. 300 g of poloxamer vehicle (Table 9) was prepared according to the manufacturing method described below.

[0144] [Table 10] Step A: Method for preparing a solution containing 300 g of iohexol: 1. Record the tare weight of a 500 mL beaker and add 150 g of water to this beaker; 2. Dispense the required masses of tromethamine, calcium disodium EDTA, and iohexol (Table 9) into this beaker and record the mass of each component added; 3. Mix the mixture until all solids are completely dissolved, optionally adding more water to aid dissolution if there is not enough water to dissolve the solids; 4. Weigh the beaker and then adjust the pH to 8.0 using 5M HCl. If the pH is already close to pH 8.0, it may be necessary to prepare a less concentrated HCl solution.

[0145] 5. Record the amount of acid used to adjust the pH by recording the weight of the beaker; 6. Add the remaining water so that the total weight of the product is 300g; 7. Record the appearance and measure the density twice; and 8. Calculate the wt / vol % of the gel formulation by multiplying the actual value of the additive (wt / wt %) by the density value (g / mL).

[0146] 300 g of this vehicle was divided into 3 portions and Poloxamer 407 was added as shown in Table 10 according to the procedure for making the poloxamer gel.

[0147] [Table 11] Step B: Method for preparing the poloxamer-iohexol solution: 1. Weigh out the mass of vehicle (from step A) required for each gel into 150 ml beakers (Table 10) and place these three beakers in the refrigerator to cool for at least 1 hour; 2. Slowly add the required amount of Poloxamer 407 to this cooled vehicle at room temperature using an overhead stirrer until the mixture is homogenous and note the appearance; 3. Place these beakers in the refrigerator overnight; 4. The next day, check that a clear solution has formed and mix carefully using a spatula or similar to ensure that the solution is homogenous; 5. Measure density using an aluminum pycnometer, record appearance, and store all samples in the refrigerator until required for testing; and 6. Calculate the wt / vol % of the gel formulation by multiplying the actual value of the additive (wt / wt %) by the density value (g / mL).

[0148] First, sol-gel transition testing was performed using 2 x 5 ml samples of each of Gel 1, Gel 2, and Gel 3. When the sol-gel temperature was between the target temperatures of 30-34°C, air-jet milled GMP linezolid powder was added to produce a solution containing 50 mg / ml linezolid, and the sol-gel temperature was tested again as described below.

[0149] 1. Dispense 200 mg of crushed linezolid into two tared clear 8 mL vials; 2. Add 3.8 mL of Gel 1, Gel 2, or Gel 3 prepared above to each vial; and 3. Shake these vials vigorously to suspend the API (Linezolid) and record appearance.

[0150] [Table 12] A 12.5% ​​w / w poloxamer gel made with a solution containing 32.743% (w / w) iohexol demonstrated the target sol-gel temperature (34° C.) for a 50 mg / ml linezolid suspension.

[0151] Example 6: Preparation of Poloxamer Delivery Vehicle To test the tolerability and long-term stability of the formulation, a delivery vehicle containing 12.5% ​​w / w poloxamer 407 and 32.7% w / w iohexol (as tested in Example 5) was prepared at an intermediate scale and then at a larger scale. These additional batches provide evidence of reproducibility.

[0152] [Table 13] The process for preparing 400 g of poloxamer vehicle for injection includes: 1. Record the tare weight of a 600 mL beaker and add 200 g of water to the beaker; 2. Dispense the required masses of tromethamine, calcium disodium EDTA, and iohexol (Table 12) into the beaker and record the mass of each component added; 3. Mixing the mixture until all solids are completely dissolved, adding additional water if necessary to aid dissolution; 4. Weighing the beaker and then adjusting the pH to 8.0 using 5M HCl; 5. adding the remaining water so that the total weight of the product is 400 g; 6. Recording the appearance and measuring the density twice; 7. Calculating the wt / vol % of the gel formulation by multiplying by the actual value of the additive (wt / wt %); 8. Weighing 175 g of iohexol solution (step 6 above) into a 250 mL beaker and placing the beaker in the refrigerator to cool for at least 1 hour; 9. Slowly adding 25 g of Poloxamer 407 (BASF Kolliphor 407, Batch No. WPNK538B (R / 003191)) to the cooled iohexol solution at room temperature using an overhead stirrer until the mixture is homogenous; 10. Put the beaker in the refrigerator overnight and the next day check that a clear solution has formed and mix carefully using a spatula or similar to ensure that the solution is homogenous; 11. Measure the density of a 30 mL sample using an aluminum pycnometer, record the appearance, and store all samples in a refrigerator until required for testing; 12. Calculating the wt / vol % of the gel formulation by multiplying the actual value of the additive (wt / wt %) by the density value (g / mL).

[0153] The poloxamer solution was sterilized by filtration using a Watson-Marlow peristaltic pump. The poloxamer solution was filtered through a Sartopore 2, 0.4 μm filter (part number 5441307H4G). The amount of poloxamer and iohexol and the sol-gel temperature of the gel were evaluated before and after filtration to determine if iohexol was retained in the filter or if the performance of the gel was altered by the filtration (Table 13).

[0154] [Table 14] The results before and after filtration showed that the gel can be filtered using a peristaltic pump and that filtration does not alter the composition and performance of the gel. The difference in the assay results before and after filtration is within the acceptable range and specifications of this assay. Filtration is the preferred method of sterilization of the gel.

[0155] This gel was then loaded with Linezolid and tested for sol-gel temperature. The results are shown in Table 14 and show that the suspension prepared at intermediate scale retains the required sol-gel temperature.

[0156] [Table 15] Example 7: In vivo pharmacokinetics and efficacy of linezolid formulations A pilot study was conducted to examine the in vivo pharmacokinetics and efficacy of linezolid suspension prepared according to the manufacturing methods described herein.

[0157] A delivery vehicle containing 16.6% (w / w) poloxamer with a 50 mg / ml linezolid suspension was prepared according to the manufacturing methods described in Examples 2-5. 0.1 ml of this linezolid suspension was injected into sheep discs as described in Example 1. As shown in Figure 2, the use of iohexol in this formulation may allow visualization of the formulation for injection. The pharmacokinetics of linezolid following intradiscal administration were measured. Figure 3 shows the amount of linezolid recovered from sheep discs following injection at a dose of 5 mg linezolid per disc.

[0158] As shown in Figure 4, the efficacy of the linezolid suspension tested indicates that administration of linezolid suspension reduced the mean bacterial load per disc by >3 logs (P=0.009). Over 60% of the discs in the test group were sterilized. Those with residual bacteria had a significantly reduced load.

[0159] Example 8: Injectability of Linezolid Formulations Injectability of the suspension is assessed using a fine 25 gauge needle that is longer than expected for human administration (4.69 inches) to ensure that the suspension does not block the needle or be too viscous to pass through the syringe. The hydrogel only or linezolid suspension is made and a 1 ml Luer lock syringe is primed with this formulation. The needle is positioned and the gel or suspension is injected through the needle. Results are recorded as follows: 1 = not injectable; no flow; or 2 = injectable; droplet flow; or 3 = injection: moderate; continuous flow. Gels and suspensions with a score of 2 or 3 are within specifications.

[0160] Example 9: Scale-up preparation of Linezolid suspension formulation Additionally, the linezolid suspension in the poloxamer-iohexol delivery solution optimized herein is manufactured on a larger scale and under current Good Manufacturing Practice (cGMP) standards, and the formulation is sterile and ready for clinical use.

[0161] 9.1 Micronization and Vialing of Linezolid Form II (API) Linezolid Form II was micronized by air jet milling to reduce the size of Linezolid Form II so that it would form a suspension in the formulation and pass through a dosing needle. Large crystals of Linezolid Form II (approximately 1-2 kilograms) were micronized under nitrogen using a LaboMill jet miller (FPSFood and Pharma Systems srl, Italy), with feed rates of 60 g / min to 160 g / min, mill pressures of 1.97-3.95 atm (2-4 bar), and venturi pressures of 1.97-3.95 atm (2-4 bar). Particle size distributions of the raw material and the air jet milled product were analyzed by laser diffraction (Sympatec GmbH, Helos Disperse). Particle size distribution data for unmilled (R1) and milled (R4) powders were collected and analyzed. Air jet milling reduced the particle size from a particle size distribution of D10 4-6 μm (D10, 10% of the sample mass is composed of particles with diameters below this range) and D90 40-50 μm (D90, 90% of the sample mass is composed of particles with diameters below this range) to D10 0.4-0.50 μm and D90 4-5 μm. Specifications for micronized Linezolid Form II were set at D10 0.2-1.0 μm and D90 3-10 μm. At 1 kg-1.5 kg scale, micronization resulted in a yield of 87%-89% of Linezolid Form II powder of specification.

[0162] Micronized linezolid Form II powder was hand filled into 10 ml Schott Type I tubular clear glass vials at 253 mg ± 2 mg per vial and closed with West 4023 / 50 grey bromobutyl elastomer stoppers with FluroTec® coating on the product contact surfaces and capped with aluminum seals. Approximately 2400 vials were filled with approximately 608 g of micronized linezolid Form II (intermediate drug product: PP353-A).

[0163] 9.2 Sterilization of Linezolid (FII) Approximately 2400 vials were sterilized by gamma irradiation using a Cobalt-60 source at approximately 23.5±10% kGy at ambient temperature. The irradiated Linezolid Form II vials were labeled PP353-A. The sterility of the irradiated Linezolid Form II powder was tested according to the sterility requirements for pharmaceutical products (EP2.6.1).

[0164] The contents of 20 vials (20 × 253 mg linezolid) were dissolved in 2500 ml of sterile water by incubating at 35-39 °C with shaking (± 200 rpm) until the product was dissolved. 200 ml of linezolid solution was filtered through a Durapore Steritest device pre-wetted with Fluid D (containing 1.0 g pepsin digest of animal tissue, 1 ml polysorbate 80, 1000 ml purified water, pH: 7.1 ± 0.2). Each membrane was washed five times with 100 ml of Fluid D. One canister contains TSB + 1% Tween + 0.07% lecithin (pancreatic digest of casein 17.0 g, papain digest of soybean 3.0 g, sodium chloride 5.0 g, dipotassium phosphate 2.5 g, glucose monohydrate 2.5 g, polysorbate 80 The other canister was filled with 100 ml of FTM (fluid thioglycollate) + 1% Tween + 0.07% lecithin (containing 0.5 g l-cystine, 0.75 g granular agar, 2.5 g sodium chloride, 5.5 g / 5.0 g glucose monohydrate / anhydrous, 5.0 g yeast extract, 15.0 g pancreatic digest of casein, 0.5 g sodium thioglycolate or 0.3 ml thioglycolic acid, 1.0 ml freshly prepared sodium resazurin solution, 10 ml polysorbate 80, 0.7 g lecithin, 1000 ml purified water, pH 7.1 ± 0.2) and incubated at 30-35 °C for 14 days. All solutions were sterilized using a validated process. After 14 days of incubation, there was no growth in the samples, indicating that the PP353-A samples were sterilized.

[0165] 9.3 Scale-up preparation of diluent (delivery vehicle) Formulation of the delivery solution (Poloxamer 407-iohexol solution) was performed at an 18.4 L (approximately 22 kg) scale and subsequently sterilized by aseptic filling into 10 mL Schott Type I clear glass vials with a target fill weight of 8.40 g (equivalent to a nominal fill volume of 7 mL). A maximum preparation size of 2400 vials was produced and designated intermediate drug product PP353-B.

[0166] [Table 16] A 22 kg preparation of delivery solution (PP353-B) was prepared as follows: 1. Adding 22.257 g of tromethamine to 11,500 g of pre-chilled (5° C.) WFI in a 20 L container and stirring until the tromethamine is dissolved; 2. adding 1.839 g calcium disodium EDTA and stirring until dissolved, followed by adding 6,303 g iohexol and stirring until dissolved; 3. (Optional) Adjusting the pH of the solution to about pH 8.0 (acceptable range pH 7.80 to pH 8.20) with 1 M hydrochloric acid; 4. adding additional pre-chilled WFI to a net weight of 18,750 g; 5. Slowly adding 2,750 g of Poloxamer 407 in approximately 100 g increments with stirring, breaking up and dispersing any agglomerated poloxamer before adding more; and 6. Add additional pre-chilled WFI to a final target weight of 22,000 g, equivalent to a nominal 18.4 L, and stir until the poloxamer is dissolved.

[0167] The formulation was cooled because poloxamer dissolves faster and has a lower viscosity at lower temperatures. The final PP353-B poloxamer solution has a density of 1.196 g / mL at 15° C.

[0168] The cooled PP353-B product was sterilized by double filtration. Using a peristaltic pump, the solution (PP353-B) was first passed through a Sartopore 2 XLG Midicap filter into an 8-glove general purpose filtration isolator and then passed through a second in-line Sartopore 2 XLG Midicap filter. The solution was cooled to reduce viscosity through the pump and filter. Sterile PP353-B was held at 15°C in a 10 L container within the isolator. The temperature control was set to establish density and weight fill of vials. The sterile solution was pumped into 10 ml Schott Type I tubular clear glass vials using a Masterflex pump at 7.0 mL (8.4 g) of sterile solution per vial, closed with West 4023 / 50 grey bromobutyl elastomer stoppers with FluroTec® coating on the product contact surfaces, and capped with an aluminum seal. Approximately 2400 vials were filled with 22 kg of solution (PP353-B).

[0169] PP353-B was tested for sterility according to the requirements stated in EP2.6.1. Twenty vials of PP353-B were distributed into two Steritest canisters and filtered. Each canister was washed with approximately 300 ml of Fluid A (0.1% peptone water). Steritest canisters were filled with 100 ml of TSB or FTM medium and incubated for 14 days. The absence of growth in the culture indicates the sterility of PP353-B.

[0170] 9.4 Rheological properties of diluents The transition temperatures of PP353-B solutions were evaluated in triplicate according to the sol-gel method described below: 1. Prepare a jacketed vessel containing deionized water and connect this vessel to a recirculating water bath; 2. Set the temperature of the water bath to 22° C. and measure the temperature in the jacketed vessel using a calibrated thermometer or thermoprobe; 3. When the water in the jacketed vessel is at 22°C and stable (± 0.5°C for at least 5 minutes), place the sample in the jacketed vessel; 4. Allow samples to equilibrate to 22°C for 15-20 minutes; 5. Remove the vial from the jacketed container and immediately invert to assess liquid-gel behavior; immediately classify the sample according to the following visual rheological characteristics: 1) liquid if it moves rapidly in the direction of gravity; 2) viscous liquid if it moves slowly downward in the direction of gravity; and 3) gel if it remains at the bottom of the vial; 6. (Optional) If the sample has not gelled, resuspend the sample as quickly as possible and return it to the jacketed vessel, increasing the temperature of the water bath by 2°C increments; 7. Record the liquid-gel behavior; 8. Once the temperature of the water in the jacketed vessel has stabilized (± 0.5°C) for 5 minutes, allow the sample to equilibrate to the same temperature for an additional 15 minutes; and 9. Repeat steps (5), (6), (7), and (8) above until the temperature reaches 40°C.

[0171] The sol-gel transition temperature for all three tested vials of PP353-B solution was 28°C. 9.5 Preparation of Linezolid Form II Suspension Formulation Linezolid suspensions were prepared using vials containing sterile micronized linezolid powder (API) (i.e., PP353-A) prepared according to the process described above (9.1 and 9.2). Each vial contained 253 mg of API. As diluents, vials containing sterile solution (i.e., PP353-B) prepared according to the method described above (9.3 and 9.4) were used. Each vial contained 7 mL of PP353-B diluent.

[0172] To make the linezolid suspension, approximately 4.8 mL of PP353-B solution was transferred to a vial of PP353-A. The vial was mixed by shaking until no solid powder was observed (approximately 1-1.5 min). This process was performed carefully to avoid an increase in the vial temperature. The final volume of one reconstituted vial is approximately 5 mL. Label the final linezolid suspension in this diluent as the drug product PP353.

[0173] The sol–gel transition temperature of PP353 suspension was evaluated in triplicate according to the sol–gel method described in Section 9.4. The sol-gel transition for all three tested vials (PP353) was 28° C. It was noted that the smaller scale non-GMP production of poloxamer hydrogel and linezolid suspension formulations had higher sol-gel transition temperatures of 32° C. to 36° C. (Examples 5 and 6), while the gels and linezolid suspensions prepared in the larger scale GMP production had lower sol-gel transition temperatures of 28° C. These results indicate that the poloxamer-based hydrogel solutions and linezolid suspensions have a wide range of sol-gel transition temperatures, from at least about 28° C. to about 36° C.

[0174] Example 10. Injectability of Linezolid formulation suspension (PP353) The linezolid suspension (PP353) made from this GMP scale preparation was further tested for injectability to access the formulation through a needle to allow administration. In this study, the injectability of the suspension (PP353) was tested using a dual needle technique and warm sweet potato as a meat substitute for the patient.

[0175] A sweet potato was warmed to 37° C. in a water bath. A 127 mm (5 inch) 18 French gauge needle was threaded through the sweet potato. This needle represents the guide needle that will be positioned in the patient under image guidance using fluoroscopy such that the needle tip is adjacent to the disc to be injected. Another 178 mm (7 inch) 22 French gauge needle was then inserted through the guide needle until its tip protruded from the 127 mm (5 inch) guide needle. This needle represents the administration needle that will be inserted into the disc to be injected. These two needles were warmed to 37° C. in the sweet potato. A 1 mL syringe filled with linezolid suspension (from PP353) that was at room temperature was attached to the administration needle. The suspension was then injected through the warm needle and the suspension was observed to extrude from the needle as a gel rather than as a droplet of liquid (FIG. 5). This experiment demonstrated that a linezolid suspension with a lower sol-gel transition temperature (i.e., PP353 at 28°C) can be injected through a warm dosing needle, and during this process the linezolid suspension transforms from a liquid to a gel inside the needle.

[0176] This observation indicates that clinically, injection of a preformed hydrogel may localize administration to the site of administration and minimize any extravasation from the injection site (e.g., the patient's spinal disc).

[0177] Example 11. Systemic Pharmacological Profile of PP353 Linezolid Suspension To measure the systemic pharmacological profile of the PP353 product, sheep (n=27, 3 for each experimental group) were administered linezolid suspension (PP353) by intradiscal disc injection according to the injection procedure described in Section 1.3 of Example 1. X-ray images were taken throughout the injection procedure to aid in the injection procedure and to identify the target vertebral disc as a measure of successful administration. Two discs of the sheep were injected with the PP353 linezolid formulation (0.1 ml of suspension containing 5 mg linezolid). A control group of sheep received the same amount of poloxamer-iohexol delivery vehicle (i.e., PP353-B) (0.1 ml). Blood samples were taken at 0 min (before administration of test substance) and at 15 min, 30 min, 1 h, 2 h, 4 h, 8 h, 16 h, 30 h, and 48 h after administration.

[0178] All blood samples were processed and quantified according to GLP (Good Laboratory Practice for nonclinical laboratory studies). The concentration of linezolid in plasma extracts was measured and determined using LC-MS / MS in accordance with National Institutes of Health (NIH) laboratory studies regulations. As shown in Figure 6, the concentration of linezolid in plasma shows a similar pattern as already observed with experimental formulation products (e.g., Examples 4-7). Injection of small volumes (e.g., 0.1 ml) of the suspension into the sheep discs may minimize potential depot effects.

[0179] In summary, these observations provide evidence for the in vivo injectability of a formulation with a relatively low gelling temperature (eg, 28° C.) and the release of linezolid from this formulation into the surrounding tissues and blood. (Additional Note) The technical ideas that can be understood from the above-described embodiment and modified examples will be described. [Item 1] (a) an effective amount of linezolid; (b) a thermosensitive hydrogel comprising poloxamer and iohexol; and optionally (c) at least one pharma- ceutically acceptable excipient. Including, The injectable pharmaceutical formulation wherein linezolid forms a suspension in said thermosensitive hydrogel. [Item 2] 2. The injectable pharmaceutical formulation according to item 1, wherein the linezolid is linezolid form II. [Item 3] 3. The injectable pharmaceutical formulation according to item 2, wherein the poloxamer is poloxamer 407, and the poloxamer 407 is present at about 9.5% to about 17% by weight of the formulation. [Item 4] 4. The injectable pharmaceutical formulation according to item 3, wherein the poloxamer 407 is present at about 10.8% to about 12.8% by weight of the formulation. [Item 5] 5. The injectable pharmaceutical formulation according to any one of items 1 to 4, wherein iohexol is present in an amount of about 14% to about 59% by weight of the formulation. [Item 6] 6. The injectable pharmaceutical formulation according to item 5, wherein iohexol is present in an amount of about 17% to about 30% by weight of the formulation. [Item 7] 7. The injectable pharmaceutical formulation according to any one of items 1 to 6, wherein the suspension gels at a temperature of about 26° C. to about 38° C. [Item 8] 8. The injectable pharmaceutical formulation according to item 7, wherein the suspension gels at a temperature of about 32° C. to about 36° C. [Item 9] 8. The injectable pharmaceutical formulation according to item 7, wherein the suspension gels at a temperature of about 26° C. to about 32° C. [Item 10] 10. The injectable pharmaceutical formulation according to any one of items 1 to 9, wherein the concentration of linezolid is about 1% to about 20% by weight of the formulation. [Item 11] 1. An injectable pharmaceutical formulation comprising about 2.5-20% linezolid form II, about 17%-30% iohexol, and about 10.8%-12.8% poloxamer by weight of the formulation. [Item 12] 12. The injectable pharmaceutical formulation according to any one of items 1 to 11, wherein the injectable pharmaceutical formulation is prepared for administration to an intervertebral disc, an intervertebral space, an intra-articular space, a site adjacent to bone edema, a ligament, a bone, a joint, a tendon, or a junction between a tendon and a bone. [Item 13] Item 13. The injectable pharmaceutical composition according to item 12, wherein the bone, joint, ligament, or tendon is a bone, joint, ligament, or tendon connected to the spine. [Item 14] Item 14. The injectable pharmaceutical composition according to Item 13, wherein the bones, joints, ligaments, or tendons connected to the spine are connected to the cervical vertebrae, thoracic vertebrae, lumbar vertebrae, or sacral vertebrae. [Item 15] 1. An injectable linezolid formulation comprising: (a) linezolid form II powder; (b) a thermosensitive hydrogel comprising poloxamer 407 and iohexol; optionally (c) at least one additive; Including, The linezolid formulation comprises: (i) grinding linezolid Form II into a defined powder; (ii) preparing a unit of linezolid powder of step (i) and sterilizing said preparation; (iii) preparing and sterilizing the thermosensitive hydrogel comprising poloxamer 407 and iohexol; and (iv) suspending the Linezolid powder of step (ii) in the thermosensitive hydrogel of step (iii). 23. A linezolid formulation for injection, which is prepared by a process comprising: [Item 16] 16. The injectable linezolid formulation according to item 15, wherein the linezolid powder is sterilized by gamma irradiation. [Item 17] 17. The injectable linezolid formulation according to item 16, wherein steps (iii) and (iv) are carried out at a lower temperature compared to steps (i) and (ii). [Item 18] 18. The injectable pharmaceutical composition according to any one of items 1 to 17 for use in medicine. [Item 19] 18. The injectable pharmaceutical composition according to any one of items 1 to 17, for use in a method for treating or preventing lower back pain in a subject, the method comprising administration of the injectable pharmaceutical composition. [Item 20] 20. The injectable pharmaceutical composition for use according to item 19, wherein the pain is acute pain, subacute pain, chronic pain, localized pain, radicular pain, referred pain, lower back pain, or neck pain. [Item 21] 21. The injectable pharmaceutical composition for use according to item 20, wherein the pain is lower back pain or neck pain associated with Modic changes or bone edema. [Item 22] 22. The injectable pharmaceutical composition for use according to item 21, wherein the subject is suspected of having or has a bacterial infection. [Item 23] 21. The injectable pharmaceutical composition for use according to item 20, wherein the injectable pharmaceutical composition is injected into an intervertebral disc, an intervertebral space, an intra-articular space, a ligament, a tendon, a tendon-bone junction, or a site adjacent to bone edema. [Item 24] 24. The injectable pharmaceutical composition for use according to item 23, wherein the injectable pharmaceutical composition is injected adjacent to or at the site of Modic changes or bone edema. [Item 25] 18. The injectable pharmaceutical composition according to any one of items 1 to 17, for use in a method for relieving or ameliorating pain in a subject and simultaneously eliminating a bacterial infection in the cervical, thoracic, lumbar, or sacral spine of said subject, said method comprising administration of said injectable pharmaceutical composition by injection into an area in, near, or around an infected vertebra. [Item 26] (a) linezolid form II powder; (b) Thermosensitive hydrogel containing poloxamer 407 and iohexol Kit including: [Item 27] 27. The kit according to item 26, further comprising a syringe and needle for injection. [Item 28] 1. A thermosensitive hydrogel for drug delivery, comprising: (a) poloxamer 407 present in the hydrogel at a concentration of about 10% to about 17% by weight of the hydrogel; (b) iohexol present in the hydrogel at a concentration of about 14.5% to about 62.5% by weight of the hydrogel; Including, The hydrogel is a thermosensitive hydrogel that forms a gel at a temperature of 26°C to 36°C.

Claims

**Claim 1** An injectable pharmaceutical preparation comprising: (a) from about 1% to about 20% by weight of linezolid in the preparation; (b) a thermosensitive hydrogel comprising from about 9.5% to about 17% by weight of poloxamer 407 and from about 17% to about 30% by weight of iohexol in the preparation; Optionally (c) at least one pharmaceutically acceptable additive; and linezolid forms a suspension in the thermosensitive hydrogel; an injectable pharmaceutical preparation. **Claim 2** The injectable pharmaceutical preparation according to claim 1, wherein the poloxamer 407 is present in the preparation at from about 10.8% to about 12.8% by weight. **Claim 3** The injectable pharmaceutical preparation according to claim 1 or 2, wherein the suspension gels at a temperature of from about 26°C to about 38°C, at a temperature of from about 32°C to about 36°C, or at a temperature of from about 26°C to about 32°C. **Claim 4** An injectable pharmaceutical preparation comprising from about 2.5% to 20% by weight of linezolid, from about 17% to 30% by weight of iohexol, and from about 10.8% to 12.8% by weight of poloxamer 407 in the preparation. **Claim 5** The injectable pharmaceutical preparation according to any one of claims 1 to 4, which is prepared for administration to an intervertebral disc, an intervertebral space, an intra-articular cavity, a site adjacent to bone edema, a ligament, a bone, a joint, a tendon, or a tendon-bone junction. **Claim 6** The injectable pharmaceutical preparation according to claim 5, wherein the bone, joint, ligament, or tendon is a bone, joint, ligament, or tendon associated with the spine. **Claim 7** The injectable pharmaceutical preparation according to claim 6, wherein the bone, joint, ligament, or tendon associated with the spine is associated with the cervical vertebrae, thoracic vertebrae, lumbar vertebrae, or sacral vertebrae. **Claim 8** A method for preparing an injectable pharmaceutical preparation, wherein the injectable pharmaceutical preparation comprises from about 1% to about 20% by weight of linezolid, from about 9.5% to about 17% by weight of poloxamer 407, and from about 14% to about 59% by weight of iohexol in the preparation, and the method comprises mixing linezolid powder with a hydrogel vehicle comprising poloxamer 407 and iohexol. **Claim 9** The injectable pharmaceutical preparation according to any one of claims 1 to 7 for use in a medicament. The injectable pharmaceutical preparation according to any one of claims 1 to 7 for use in a method of treating or preventing the target low back pain, said method comprising administration of said injectable pharmaceutical preparation, an injectable pharmaceutical preparation for use. The injectable pharmaceutical preparation for use according to claim 10, wherein said pain is acute pain, subacute pain, chronic pain, local pain, radicular pain, associated pain, low back pain, or neck pain. The injectable pharmaceutical preparation for use according to claim 10, wherein said pain is low back pain or neck pain associated with Modic changes or bone marrow edema, Optionally, the subject is suspected of having a bacterial infection or is infected with bacteria, an injectable pharmaceutical preparation for use according to claim 11. The injectable pharmaceutical preparation is to be injected into the intervertebral disc, intervertebral space, joint cavity, ligament, tendon, tendon-bone junction, or a site adjacent to bone marrow edema, Optionally, the injectable pharmaceutical preparation is injected adjacent to or into the site of Modic change or bone marrow edema, an injectable pharmaceutical preparation for use according to claim 11. The injectable pharmaceutical preparation according to any one of claims 1 to 7 for use in a method of alleviating or relieving the pain of a subject and simultaneously removing a bacterial infection in the cervical vertebrae, thoracic vertebrae, lumbar vertebrae, or sacral vertebrae of said subject, said method comprising administration of said injectable pharmaceutical preparation by injection into an area in the infected vertebral bone, an area near the infected vertebral bone, or an area around the infected vertebral bone, an injectable pharmaceutical preparation for use. A kit comprising (a) a first vial containing linezolid powder, and (b) a second vial containing a hydrogel vehicle containing poloxamer 407 and iohexol for forming an injectable pharmaceutical preparation by mixing, and the injectable pharmaceutical preparation after mixing comprises (a) 1% to 20% by weight of linezolid in said preparation, (b) a thermosensitive hydrogel containing 9.5% to 17% by weight of poloxamer 407 and 14% to 59% by weight of iohexol in said preparation, and linezolid forms a suspension in said thermosensitive hydrogel, a kit. The kit according to claim 15, further comprising an injectable syringe and needle. ​ ​

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