Nanostructured delivery device for poorly water-soluble Anti-tubercular drugs and method thereof

Abstract

Disclosed herein a nano-structured lipid carrier for poorly water-soluble anti-tubercular drugs and method thereof to provide co-therapy of drugs in order to get the synergistic effect via enhanced bioavailability of each drug, and avoidance of first pass metabolism, will increase therapeutic effect and reduce dose frequency, which ultimately enhance patient compliance.

Description

Field of the InventionThis invention, in general relates to a pharmaceutical formulation of anti-tubercular drugs. More particularly, the present invention provide an enhanced bioavailable formulation of poorly water-soluble anti-tubercular drugs employing unique combination of Drug : Lipid: Oil which ultimately results in nanoparticulate size of drug enabling effective delivery of the drug. Background of the InventionBackground description includes information that may be useful in understanding the present invention. It is not an admission that any of the information provided herein is prior art or relevant to the present invention, or that any publication specifically or implicitly referenced is prior art.Poorly water-soluble anti-tubercular drugs such as Rifabutin (RFB), is a lipophilic, semi synthetic antibiotic prescribed for the treatment of atypical mycobacterial infections as well as drug susceptible tuberculosis infections. The challenges in its usage include low oral bioavailability (-20%) mainly due to its low solubility and extensive first pass metabolism.Poorly water-soluble anti-tubercular drugs such as Azithromycin, a nitrogen-containing macrolide (azalide-derived from erythromycin) is used for treating respiratory tract infections, skin and genital infections. Azithromycin can effectively inhibit the growth of bacteria, by interfering with their protein synthesis. It binds to the 50S subunit of the bacterial ribosome, thus inhibiting translation of mRNA. It has bactericidal activity against strains of Mycobacterium avium complex (MAC) infections and a variety of enteric bacterial pathogens. However, the therapeutic use of this potent antibiotic is limited due to its low bioavailability (36%), high dose (500 mg, as used in tuberculosis and MAC infections) and dose related adverse effects (diarrhoea, abdominal pain, chest pain, vomiting, dizziness), which leads to poor patient compliance.Rifabutin and Azithromycin are the most preferred choice of drugs for the first line and second line treatment of TB respectively. They are often given together for the management and curing of TB. Both thee drugs have different mechanism of action. Rifabutin is bactericidal drug, while azithromycin in bacteriostatic in nature. However, they both have their limitations like poor solubility and poor oral bioavailability, which result into prescription of higher doses, leading to untoward adverse effects.There are various reported works which have been done on delivery carrier to improve bioavailability of poorly water-soluble anti-tubercular drugs. EP2369923A1 titled Methods for inhibiting gram-positive bacteria using non-phospholipid lipid vesicules relates to a method for inhibiting gram-positive bacteria with a composition comprising at least one non-phospholipid lipid vesicle comprises a lipid comprising a quaternary ammonium head group.CN105708799A titled Nano-structural lipid carrier pharmaceutical composition and preparation method describes the nano-structural lipid carrier containing pharmaceutical composition prepared by the invention, which can greatly overcome the shortcomings of the insoluble drug which is not easy to dissolve in water, low in oral bioavailability and the like. The preparation method is simple and controllable, good in repeatability, and an available drug delivery system is provided for the insoluble drug.WO2009050217A2 titled improved pharmaceutical dry powder compositions for inhalation relates to a spray dried powder for use in dry inhalers, comprising particles (A) comprising active material, said particles being at least partially coated (C1, C2) with an active material so that the flowing and dispersing properties of the powder are enhanced.EP3177269A1 titled Remote loading of sparingly water-soluble drugs into lipid vesicles relates to a compositions and methods for remote loading drugs with low water solubility ( < 2 mg / mL ). In the preferred embodiment the drug in the solubilizing agent is mixed with the liposomes in aqueous suspension so that the concentration of solubilizing agent is lowered to below its capacity to completely solubilize the drug. However, this process as described in the literature has been limited to drugs that are freely soluble in aqueous solution or solubilized as a water-soluble complex.EP3085360A1 titled Lipid based nanocarrier compositions loaded with metal nanoparticles and therapeutic agent relates to a non-polymeric lipid-based nanocarrier compositions loaded with metal nanoparticles and at least one therapeutic agent, useful .as agents for transportation, vectorization, cellular delivery cellular targeting or cellular localization of at least one therapeutic agent.US9549901B2 titled Lipid-polymer hybrid particles, wherein the particle comprising an aqueous core, a first amphiphilic layer surrounding the aqueous core, a polymeric matrix surrounding the first amphiphilic layer; and one or more active agents, wherein at least one of the active agents is an immunostimulatory agent comprising a toll receptor (TLR) ligand ss / dsRNA, a polyI:C polynucleotide, or a CpG polynucleotide.US20170071858A1 titled Liposomes useful for drug delivery relates to a liposome compositions containing substituted ammonium and / or polyanion, and optionally with a desired therapeutic or imaging entity. The present invention also provide methods of making the liposome compositions provided by the present invention, wherein said liposomes encapsulating irinotecan and triphosphate and comprising one or more phospholipid, said composition having a mole ratio of irinotecan to lipid between 0.15:1 to 1.5:1.The above arts have been worked upon to improve the formulation of poorly soluble drugs however solubility and dissolution rate of hydrophobic drugs still remain critical challenges to overcome for the pharmaceutical scientists. In the drug discovery and product development process high number of hydrophobic drugs are entering and the limitations of their usage due to their issues related with bioavailability is now more important to consider and resolved.To obviate these hurdles in exploiting the therapeutic benefits of these drugs, nanostructured lipid carriers (NLC) of both these drugs for simultaneous oral delivery needs to be developed, which will reduce frequency, deliver medications more efficaciously, ultimately reducing patient avoidance.Therefore, it is required to develop an improved nano-structured formulation and method to produce the formulation, which obviates the drawback associated with the prior arts. Summary of the InventionThis summary is provided to introduce concepts related to systems and methods for an adaptive hearing aid, the concepts are further described below in the detailed description. This summary is neither intended to identify essential features of the claimed subject matter nor is it intended for use in determining or limiting the scope of the claimed subject matter.It is a principal objective of the present invention to develop lipid based nanocarriers system of poorly water-soluble anti-tubercular drugs, so as to increase the oral bioavailability of these drugs.It is another objective of the present invention is to provide the best way of simultaneous oral delivery of poorly water-soluble anti-tubercular drugs which includes both Rifabutin and Azithromycin in their therapeutic doses.It is another objective of the present invention to develop a nanocarrier which is suitable for the drug candidate with poor water solublility, using regulatory accepted excipients.It is yet other objective of the present invention to provide an evaluation of prepared nanocarrier for its physical (nanoparticles size distribution) and chemical (drug content) stability.It is yet other objective of the present invention to develop a lipid nanocarriers of poorly water-soluble anti-tubercular drugs for simultaneous oral delivery, which will reduce frequency of administration, deliver medications more efficaciously, ultimately reducing the patient avoidance.The above and other objectives of the present invention are achieved according to the following embodiments of the present invention. However, the disclosed embodiments are exemplary based on the preferred and best mode of the invention and not limit the scope of the present invention.In accordance with one embodiment of the present invention, a nano-structured lipid carrier which comprises of active ingredients alongwith solid and liquid lipids in a ratio of 70:30 to 99:1.In accordance with another embodiment of the present invention, it describes nano structured lipid carriers, wherein said carriers comprised of drug : Lipid: Oil in one phase and mixture of surface-active agents in another phase, which ultimately results in nanoparticulate size of drug which delivers the drug into the vicinity of the target site in a sustained release manner.In accordance with another embodiment of the present invention, there is provided a nano-structured lipid carrier, which ultimately results in nanoparticulate size of drug which delivers the drug into the vicinity of the target site in sustained release manner.In accordance with another embodiment of the present invention, it describes a method for preparing nano structured carrier for poorly water-soluble anti-tubercular drugs employing solvent diffusion evaporation method comprising dissolving active drug of anti-tubercular, lipid and oil employing alcohol and the same heating at 60-70°C, the resultant solution mixture is added drop wise to 1% v / v Tween 80 and Transcutol P under mechanical stirring, the resulted mixture is kept overnight under continuous stirring to evaporate alcohol. In accordance with another embodiment of the present invention, there is provided a method for simultaneous oral delivery of nanostructured lipid carriers of both the agents.These and other embodiments, methods, and features of the subject matter will become more fully apparent when the following detailed description is read with the accompanying experimental details. However, both the foregoing summary of the subject matter and the following detailed description of it represent one potential embodiment and are not restrictive of the present disclosure or other alternate embodiments of the subject matter.Description of the InventionThe following is a detailed description of embodiments of the disclosure depicted in the accompanying drawings. The embodiments are in such detail as to clearly communicate the disclosure. However, the amount of detail offered is not intended to limit the anticipated variations of embodiments; on the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the present disclosure.The present invention relates with the field of pharmaceutical preparations wherein a novel nanocarrier system based on biocompatible, physiological lipids, developed for improving the bioavailability of poorly water-soluble anti-tubercular drugs- Rifabutin and Azithromycin. The said formulation comprising unique combination of Drug : Lipid: Oil in one phase and mixture of surface active agents in another phase, which ultimately results in nanoparticulate size of drug which delivers the drug into the vicinity of the target site in sustained release manner. Further novel strategy utilized to give co-therapy of drug azithromycin with drug rifabutin in order to get the synergistic effect via enhanced bioavailability of each drug, and avoidance of first pass metabolism, will increase therapeutic effect and reduce dose frequency, which ultimately enhance patient compliance.The Nanocarrier prepared according to embodiments of the present invention is developed as a system for administration of poorly soluble drugs and targeting the site of infection. The invention provides the outlook on the systematic development Nanocarriers for drugs such as rifabutin and azithromycin by using the novel QbD based approach which showed better safety profiles and enhanced pharmacokinetic parameters.The solid lipids and oil are selected from glyceryl monostearate, glyceryl behenate, Gelucire, and / or Captex 200P, isopropyl Myristate, or Oleic Acid.The nano-structured carrier and method used in the present invention, wherein poorly water-soluble anti-tubercular drugs selected from rifabutin, azithromycin and applicable to poorly water-soluble drugs.The nanostructured carrier and method used in the present invention, wherein the nanoformulations are in a range of 0-500 nm, preferably in the range of 200-500 nm, more preferably in the range of 300-400 nm.Based on these objectives and methodologies, the invention will have an application of increase in pharmacokinetic profile of therapeutic agents with nanoparticulate formulations. The material and process used, are economic and the methods described above are easy to perform. According to the present invention, there is provided a method for simultaneous estimation of exemplary poorly water-soluble anti-tubercular drugs i.e rifabutin and azithromycin in biological matrix i.e. blood, plasma, serum and urine.The following examples are included to demonstrate preferred embodiments of the invention. The various examples herein are disclosed various embodiments and best mode of the present invention. However, the person skilled in the art will appreciate that various changes can be made in the specific embodiments disclosed herein and the similar result should be obtained without departing from the essence and scope of the present invention. Example 1Preparing Nanostructured lipid carrier (NLC) of rifabutin:The Rifabutin Nanostructured lipid carrier (NLC) are prepared and optimized by solvent diffusion evaporation method with minor modifications. Rifabutin, GMS and Oleic Acid is dissolved in ethanol by heating at 60-70°C. The drug: lipid: oil ratio is maintained at 1: 2 : 0.5 w / w / w and the solution mixture is added drop wise to 1% v / v Tween 80 and Transcutol P (in ratio of 1: 1 w / w) solution maintained at 60-70°C, under mechanical stirring. The secondary emulsion resulted is kept overnight under continues stirring to evaporate ethanol. The formulated nanoparticles are recovered by centrifugation at 20,000 rpm for 60 minutes, washed with distilled water and lyophilized. The nanocarrier are loaded rifabutin, evaluated for its physical (nanoparticles size distribution) and chemical (drug content) stability. Example 2Preparing Nanostructured lipid carrier (NLC) of azithromycin:The azithromycin Nanostructured lipid carrier (NLC) were prepared and optimized by solvent diffusion evaporation method with minor modifications. Azithromycin, Gelucire and Captex 200P was dissolved in ethanol by heating at 60-70°C. The drug: lipid: oil ratio was maintained at 1: 2 : 0.5 w / w / w and the solution mixture was added drop wise to 1% v / v Tween 80 and Transcutol P (in ratio of 1: 1 w / w) solution maintained at 60-70°C, under mechanical stirring. The secondary emulsion resulted was kept overnight under continues stirring to evaporate ethanol. The formulated nanoparticles were recovered by centrifugation at 20,000 rpm for 60 minutes, washed with distilled water and lyophilized. The nanocarrier are loaded azithromycin, evaluated for its physical (nanoparticles size distribution) and chemical (drug content) stability. Example 3The developed Nanostructured lipid carrier (NLC) of both drugs rifabutin and azithromycin are utilized for simultaneous oral delivery wherein there is reduction of frequency of administration, Rifabutin gets deliver more efficaciously, ultimately it reduces the patient avoidance.Example 4In-vitro drug release kineticsNanocarrier has showed initially burst release afterwards sustained release for longer duration i.e. dual release pattern which is due to the release of the drug from the surface of nanocarrier results in initial burst followed by release of captured drug through membrane-controlled or diffusion assisted mechanism. The release pattern of Rifabutin loaded Nanocarrier is revealed that it represents the sustained release kinetics in comparison to plain drug. Figure 1: Drug release studies of Rifabutin Nanocarrier formulation in SGF (pH-2); SIF (pH-6.8) and in PBS (pH-7.4) Drug release kineticsDrug release from the above nanoformulation was fitted into different release kinetic models such as zero order, first order, Higuchi models, Hixon-Crowell and Korsemeyer-Peppas model. It is observed that, the release kinetic studies showed Korsmeyer Peppas model, governs diffusion mediated drug release from the aforesaid nanocarrier system.Table 1: Release kinetic models for Rifabutin Nanocarrier formulationFormulation in Media Drug release Models (r2) Zero order First order Higuchi Hixon-Crowell Korsemeyer-PeppasSGF (pH-2) 0.7123 0.7034 0.8906 0.4164 0.97663SIF (pH-6.8) 0.9301 0.4405 0.9632 0.3215 0.9712PBS (pH-7.4) 0.9235 0.4276 0.9567 0.7896 0.9768Pharmacokinetic estimation of Nanocarrier SystemRifabutin and its nanocarrier administered in single dose in the rats, the nanocarrier shown sustained and longer duration drugs release pattern in plasma above its minimum inhibitory concentration whereas the rifabutin plain drug is cleared from the circulation within 18-24 h.Estimation of Drug from Blood (Analytical method)The RP-HPLC (Agilent infinity 1220 LC) method is validated for linearity, accuracy, precision (Interday precision, Intraday precision), repeatability and robustness. RP-HPLC method is developed on C-18 column (250 x 4.6 mm, 5 μm) with UV detector. Mobile phase containing Acetonitrile and Ammonium Acetate buffer (55:45 v / v) pH 4.5 is used. The flow rate is 1.25 ml / min and effluents are analysed at wavelength of 240 nm. Figure 2 1: RP-HPLC Calibration curve and chromatogram of Rifabutin in Blood PlasmaFigure 32: Plasma concentration profile curve for Rifabutin and Rifabutin Nanocarrier.Cmax and Tmax of Rifabutin nanocarrier significantly differed from the plain drug. However, the AUC0-8 (μg.h) / mL and the mean residence time (MRT) for nanocarrier significantly (p<0.001) increased as compared to a plain rifabutin (Table 2)Table 2: Pharmacokinetic parameters of Rifabutin Plain Drug and Rifabutin NanocarrierParameters RifabutinPlain Drug Rifabutin NanocarrierCmax (μg / mL) 2.9±1.47 3.44±1.74Tmax (h) 2.10± 1.10 64±1.62kel 0.18 ±0.011 0.01 ± 0.003t1 / 2(h) 3.92±0.58 12.89± 4.19AUC0-8 (μg.h) / mL 24.13 ± 4.16 183.74±3.35***MRT (h) 4.90± 1.23 41.11± 3.02***Relative Bioavailability 1 5.8*** P < 0.001 as compared to group with the plain drug.After the administration of nanocarrier, the availability of rifabutin in sustained manner above the Minimum Inhibitory Concentration for more than 3 days, favours its therapeutic goal in treatment of tuberculosis and MAC infection where the infection is localized and frequency of drug intake can be reduced as the drug available for longer duration.Example 5In-vitro drug release kineticsRelease mechanism of azithromycin from its nanocarrier is studied in different dissolution medium systems. In SGF, nanocarrier shown stability and not affected by the medium containing SGF, while in simulated intestinal fluid (SIF) nanocarrier are shown sustained release kinetics up to 02 days and similar pattern shown in physiological buffer system (PBS) upto 04 days. Nanocarrier showed initially burst release upto 12 h with nearly 40 % of the drug release afterwards release is sustained for longer duration upto 96 h with a cumulative drug release of about 63.46 %. i.e. dual release pattern which is due to the release of the drug from the surface of nanocarrier results in initial burst followed by release of captured drug through membrane-controlled mechanism. Figure 4: Drug release studies of Azithromycin Nanocarrier formulation in SGF (pH-2); SIF (pH-6.8) and in PBS (pH-7.4) Drug release kineticsDrug release from the above nanoformulation is fitted into different release kinetic models such as zero order, first order, Higuchi models, Hixon-Crowell and Korsemeyer-Peppas model. It is observed that, the drug release from Azithromycin Nanocarrier formulation followed Higuchi model, which is based on the Fick'slaw on diffusion.Table 31: Release kinetic models for Azithromycin Nanocarrier formulationFormulation in Media Drug release Models (r2) Zero order First order Higuchi Hixon-Crowell Korsemeyer-PeppasSGF (pH-2) 0.7585 0.6974 0.9143 0.3952 0.9878SIF (pH-6.8) 0.9215 0.4105 0.9732 0.3215 0.9533PBS (pH-7.4) 0.9355 0.4012 0.9683 0.8165 0.9519Pharmacokinetic estimation of Nanocarrier SystemAzithromycin and its nanocarrier administered in single dose in the rats, the nanocarrier shown sustained and longer duration drugs release pattern in plasma above its minimum inhibitory concentration.Estimation of Drug from Blood (Analytical Method)A C-18 column (250 x 4.6 mm, 5 μm) and UV Detector with mobile phase containing Methanol and Phosphate buffer (98:02 v / v) pH 7 is used. The flow rate was 1.00 ml / min and samples are monitored at 254 nm. The RP-HPLC method is extensively validated as per the ICH requirements. Figure 5: HPLC Calibration curve and chromatogram of Azithromycin in Blood PlasmaFigure 6: Plasma Concentration time profile curve for Azithromycin Plain drug and Azithromycin NanocarrierTable 5: Pharmacokinetic parameters of Plain Drug and Azithromycin NanocarrierParameters Azithromycin Plain Drug AzithromycinNanocarrierCmax (μg / mL) 11.92 ±1.47 14.84±1.74Tmax (h) 4.00 ± 1.10 21.30 ±1.62kel 0.21 ±0.023 0.010 ± 0.006t1 / 2(h) 32.90±0.48 112.40 ± 3.65AUC0-8 (μg.h) / mL 578.10 ± 4.20 1302.45±4.45***MRT (h) 12.90 ± 2.34 68.11 ± 5.02***Relative Bioavailability 1 4.5*** P < 0.001 as compared with the plain drug group.It will be appreciated by those skilled in the art that the foregoing description is in respect of preferred embodiments and that various alterations and modifications are possible within the broad scope of the appended claims without departing from the spirit of the invention with the necessary modifications. Based on the description of disclosed embodiments, persons skilled in the art can implement or apply the present disclosure. Various modifications of the embodiments are apparent to persons skilled in the art, and general principles defined in the specification can be implemented in other embodiments without departing from the spirit or scope of the present disclosure. Therefore, the present disclosure is not limited to the embodiments in the specification but intends to cover the most extensive scope consistent with the principle and the novel features disclosed in the specification.

Claims

1. A nano-structured lipid carrier for poorly water-soluble anti-tubercular drugs comprises of active ingredients alongwith nano structured lipid carriers containing solid and liquid lipids in a ratio of 70:30 to 99:1.

2. The nano-structured carrier as claimed in claim 1, wherein said carriers comprised of drug : Lipid: Oil in one phase and mixture of surface-active agents in another phase, which ultimately results in nanoparticulate size of drug which delivers the drug into the vicinity of the target site in a sustained release manner.

3. The nano-structured carrier as claimed in claim 1, wherein said device comprises of nanoformulation having an active : Lipid: Oil in one phase and mixture of surface active agents in another phase, which ultimately results in nanoparticulate size of drug which delivers the drug into the vicinity of the target site in sustained release manner.

4. The nano-structured carrier as claimed in claim 2, wherein the drug:lipid:oil ratio is maintained at 1:2:05 w / w / w.

5. A method for preparing nano structured carrier for s poorly water-soluble anti-tubercular drugs employing solvent diffusion evaporation method comprising:dissolving active drug of anti-tubercular, lipid and oil employing alcohol and the same heating at 60-70°C; the resultant solution mixture is added drop wise to 1% v / v Tween 80 and Transcutol P under mechanical stirring; (a.) the resulted mixture is kept overnight under continuous stirring to evaporate alcohol.

6. The method as claimed in claim 5, wherein the solid lipids and oil are selected from glyceryl monostearate, glyceryl behenate, Gelucire, and / or Captex 200P, isopropyl Myristate, or Oleic Acid.

7. The nano-structured carrier and method as claimed in any of the above claims, wherein poorly water-soluble anti-tubercular drugs selected from Rifabutin, Azithromycin and applicable to poorly water-soluble drugs.

8. The nanostructured carrier and method of preparation as claimed in any of the above claims, wherein the nanoformulations are in a range of 0-500 nm, preferably in the range of 200-500 nm, more preferably in the range of 300-400 nm.

9. The method as claimed in claim 4, wherein the ratio of said drug:lipid: oil is maintained at 1: 2 : 0.5 w / w / w.

10. The nanostructured carrier as claimed in any of the above claims are meant to be administered simultaneously for oral delivery.