Methods of preparing drug eluting microsphere suspensions, drug eluting microsphere suspensions, and uses thereof

Abstract

This invention relates to the field of biomedical technology, providing a method for preparing a drug-eluting microsphere suspension, the drug-eluting microsphere suspension, and its applications. The method includes: S1. Removing the storage solution from the drug-eluting microspheres to obtain a microsphere precipitate; S2. Adding a chemotherapy drug solution to the microsphere precipitate to load the drug into the microspheres; S3. Mixing physiological saline and a non-ionic contrast agent at a volume ratio of 1.5:1 to prepare a dilution medium; S4. Adding the dilution medium prepared in step S3 to the microspheres after drug loading in step S2, so that the total suspension volume reaches a preset multiple of the microsphere precipitate volume, obtaining a microsphere suspension; S5. Shaking the microsphere suspension obtained in step S4 to mix thoroughly. This invention significantly reduces postoperative chemical stimulation pain by increasing the dilution factor of the drug-eluting microsphere suspension, while unexpectedly improving tumor response, achieving a synergistic effect of pain reduction and efficacy enhancement.

Description

Technical Field

[0001] This invention relates to the field of biomedical technology, and in particular to a method for preparing a drug-eluting microsphere suspension, the drug-eluting microsphere suspension, and its applications. Background Technology

[0002] Transarterial chemoembolization (TACE) is one of the standard local treatment methods for unresectable hepatocellular carcinoma (HCC). Drug-eluting bead TACE (DEB-TACE) involves injecting microspheres loaded with chemotherapeutic drugs into the tumor's feeding artery via an artery, achieving the dual effects of tumor ischemic necrosis and continuous local chemotherapy.

[0003] In DEB-TACE procedures, the preparation of the microsphere suspension is a standard step. Based on traditional protocol literature and clinical practice: (1) Preparation method of microsphere suspension In traditional methods, the preparation of microsphere suspensions typically follows product instructions or institutional operating procedures. Taking commonly used DCBead™ or CalliSphere™ microspheres as examples, the standard preparation process is as follows: after removing the storage solution, loading the chemotherapy drug (such as epirubicin or doxorubicin), followed by adding a mixture of physiological saline and contrast agent to achieve a total suspension volume of 5-10 mL (based on 1 mL of microspheres). For instance, in a study using 40 μm microspheres, the preparation method involved loading 50 mg of doxorubicin onto 1 mL of microspheres and then diluting it in 4 mL of contrast agent (total suspension volume approximately 5 mL, dilution factor approximately 5 times).

[0004] (2) Current understanding of dilution factor and its limitations In traditional approaches, the dilution factor of the microsphere suspension is mainly considered as a parameter for ease of operation, and its purpose is limited to: ① ensuring that the microspheres do not block the catheter during injection; ② ensuring that the microspheres are properly dispersed in the blood flow; ③ facilitating intraoperative monitoring of the embolization effect through angiography.

[0005] The consensus of experts from the Korean Liver Cancer Association once recommended diluting the microsphere mixture to 30-50 mL to facilitate uniform embolization, but this recommendation has the following fundamental limitations: ① The method for calculating the dilution factor (total suspension volume / microsphere volume) is not clearly defined, leading to differences among different operators; ② Its purpose was only to ensure the uniformity of embolization, without recognizing the independent value of high-fold dilution in regulating local drug concentration, reducing chemical irritation, and reducing postoperative pain; ③ There is a lack of clinical data to support its analgesic effect, and no strategy for selecting dilution ratios based on individual patient characteristics has been proposed.

[0006] (3) Current understanding of post-DEB-TACE pain and technological gaps Existing research indicates a high incidence of abdominal pain after DEB-TACE, with approximately 49%–57.3% of patients experiencing moderate to severe pain requiring pharmacological intervention. Multiple studies have identified risk factors for postoperative pain, including non-superselective embolization, presence of portal vein tumor thrombus, tumor proximity to the liver capsule, and poor liver function reserve (Child-Pugh B).

[0007] Regarding the mechanism of pain, traditional approaches generally suggest: ① Ischemic injury – after embolization, the tumor and surrounding liver tissue become ischemic, edematous, and necrotic, stimulating the liver capsule and surrounding nerves; ② Inflammatory response – embolization-induced release of local inflammatory mediators; ③ Liver capsule stretching – when the tumor is located close to the liver capsule, it is more likely to cause pain.

[0008] However, traditional approaches have a fundamental blind spot in their understanding of pain mechanisms: while recognizing the vascular irritant properties of chemotherapy drugs, they have consistently viewed it as a side effect of ischemic injury, rather than an independent, manageable source of pain. A 2022 study published in the *Journal of Translational Medicine* clearly states that post-DEB-TACE pain can be attributed to "acute ischemia and necrosis, cell debris-induced inflammation, and abnormal tissue tension." The study did not mention "direct chemical stimulation by high concentrations of chemotherapy drugs" as an independent mechanism, nor did it propose a solution to achieve source analgesia by adjusting the dilution factor to reduce local drug concentration.

[0009] (4) The passivity and limitations of existing analgesia strategies Currently, postoperative pain management after DEB-TACE mainly relies on pharmacological interventions, including: ① intraoperative intra-arterial lidocaine injection; ② postoperative stepwise analgesia (non-opioid → opioid); ③ prophylactic glucocorticoids, which have been explored in some studies. These strategies are all symptomatic treatments and do not address the root cause of pain at a technical level, thus having the following inherent limitations: ① drug-related side effects (such as nausea, vomiting, and respiratory depression); ② incomplete analgesic effect; ③ increased medical costs and medication complexity.

[0010] Traditional approaches fail to provide a technical solution for achieving "source analgesia" by optimizing microsphere suspension preparation parameters.

[0011] In summary, the objective drawbacks of traditional solutions include: Disadvantage 1: There is a blind spot in the understanding of pain mechanisms—ignoring the independent intervention value of chemical stimulation; Traditional approaches have failed to reveal "chemical stimulation" as a quantifiable source of pain independent of ischemic injury and precisely modulated by dilution factors. This blind spot has limited pain intervention targets to "ischemia-inflammation," missing the technical pathway of achieving source analgesia by regulating local drug concentration.

[0012] Disadvantage 2: The dilution factor is only considered as an operational parameter, not a parameter for regulating efficacy / safety; In traditional protocols, the selection of dilution factors for microsphere suspensions lacks scientific basis and relies primarily on operator experience. The dilution factor is simply considered an operational parameter to ensure smooth injection, and its correlation with postoperative pain, tumor response, and other clinical outcomes is not recognized. Furthermore, a dilution factor decision-making system based on individualized factors such as tumor anatomical location, liver function classification, cannulation selectivity, and tumor blood supply characteristics has not been established.

[0013] Disadvantage 3: Existing pain relief strategies are all drug-based rescues, without addressing the root cause; Current pain management strategies primarily focus on postoperative drug intervention or intraoperative adjuvant medication, which is a "passive response" approach. Traditional methods fail to provide a technical solution for achieving "source pain relief" by optimizing operational parameters.

[0014] Disadvantage 4: Neglecting the synergistic effect of "pain reduction-efficacy enhancement"; In traditional approaches, optimizing operational parameters often involves a trade-off between "analgesia" and "therapeutic efficacy." For example, overly gentle embolization may reduce pain but affect efficacy; overly thorough embolization may enhance efficacy but worsen pain. Traditional approaches lack a technical solution that can simultaneously reduce pain and improve tumor response, and they fail to recognize that high-dilution methods can achieve a synergistic effect of "pain reduction and efficacy enhancement" by promoting uniform distribution of microspheres at the distal end. Summary of the Invention

[0015] The purpose of this invention is to solve at least one technical problem in the background art and to provide a method for preparing a drug-eluting microsphere suspension, the drug-eluting microsphere suspension, and its application.

[0016] To achieve the above objectives, the present invention provides a method for preparing a drug-eluting microsphere suspension, comprising the following steps: S1. Remove the storage solution from the drug-eluting microspheres to obtain a microsphere precipitate; S2. Add a chemotherapy drug solution to the microsphere precipitate to load the drug into the microspheres; S3. Mix physiological saline and non-ionic contrast agent at a volume ratio of 1.5:1 to prepare a dilution medium; S4. Add the dilution medium prepared in step S3 to the microspheres after the drug has been loaded in step S2, so that the total suspension volume reaches a preset multiple of the microsphere precipitation volume, and obtain a microsphere suspension. S5. Shake the microsphere suspension obtained in step S4 to mix it well.

[0017] According to one aspect of the invention, the total suspension volume is 30 to 100 times the microsphere precipitation volume.

[0018] According to one aspect of the invention, the chemotherapeutic drug is a positively charged chemotherapeutic drug capable of being loaded onto drug-eluting microspheres via an ion exchange mechanism.

[0019] According to one aspect of the invention, the chemotherapeutic agent is one or more of anthracyclines, irinotecan, gemcitabine, or oxaliplatin.

[0020] According to one aspect of the present invention, the drug-eluting microspheres are drug-loaded microspheres with a particle size of 40 μm or more.

[0021] According to one aspect of the invention, the particle size of the drug-loaded microspheres is 100-1200 μm.

[0022] According to one aspect of the invention, the particle size of the drug-loaded microspheres is 100-300 μm, 300-500 μm, or 500-700 μm.

[0023] According to one aspect of the present invention, the loading of the drug into the microspheres is performed by: adding a chemotherapy drug solution to the microsphere precipitate, shaking to mix, and allowing to stand, so that the drug is fully loaded into the microspheres.

[0024] According to one aspect of the present invention, determining the total suspension volume based on preset conditions such as tumor anatomical location, liver function grade, cannulation selectivity, and tumor blood supply characteristics includes: When the preset conditions are: cannulation selectivity is subsegmental superselectivity and / or tumor blood supply is rich blood supply, the total suspension volume is 30 to 50 times the microsphere precipitation volume; When the preset conditions are: the tumor is close to the liver capsule, the liver function is Child-Pugh B, and / or the tumor blood supply is poor, the total suspension volume is 50 to 100 times the microsphere precipitation volume.

[0025] To achieve the above objectives, the present invention also provides a drug-eluting microsphere suspension, which is prepared by the above-described drug-eluting microsphere suspension preparation method.

[0026] To achieve the above objectives, the present invention also provides the use of the above-mentioned drug-eluting microsphere suspension in the preparation of a medicament for relieving pain after transarterial chemoembolization of drug-eluting microspheres.

[0027] According to the present invention, compared with the conventional solution, the present invention has the following beneficial effects, which can be confirmed by the above embodiments and comparative examples.

[0028] I. Significantly reduces severe postoperative pain, achieving pain relief at the source; Traditional DEB-TACE procedures typically use microsphere suspensions diluted 5-10 times, resulting in a high incidence of severe postoperative pain (Visual Analogue Scale score ≥7), often requiring patients to rely on opioid analgesia. This invention increases the microsphere suspension dilution factor to 30-100 times, achieving high dispersion of the microspheres in the bloodstream and significantly reducing the peak concentration of local chemotherapy drugs. This directly reduces the chemical irritation of the drug to the blood vessel wall and surrounding tissues, intervening at the source of pain through chemical stimulation.

[0029] This invention significantly reduces the incidence of severe postoperative pain, and the effect increases with the dilution factor, achieving a technological breakthrough in active analgesia from the source of chemical stimulation.

[0030] Second, it achieves a synergistic effect of pain reduction and increased efficacy, breaking with traditional perceptions; It is well known that the antitumor effect of chemotherapy drugs is usually positively correlated with their local concentration. Conventionally, increasing the dilution factor (reducing the local drug concentration) is expected to weaken the antitumor efficacy. However, this invention unexpectedly discovered that high dilutions, while significantly reducing pain, actually increased the objective response rate to tumors.

[0031] The mechanism behind this counterintuitive effect lies in the fact that high-level dilution allows for more uniform and distal distribution of microspheres in the bloodstream, improving the embolic integrity of the tumor-feeding arteries and thus enhancing the antitumor effect without relying on higher drug doses. This invention breaks the technical prejudice that dilution reducing local concentration inevitably weakens efficacy, achieving a synergistic effect of pain relief and therapeutic enhancement.

[0032] Third, we provide individualized dilution factor selection options to optimize benefits for different groups of people; This invention further provides a differentiated dilution selection strategy based on patient clinical characteristics. Subgroup analysis showed that high dilutions (50-100 times) had consistent analgesic effects across different clinical subgroups (gender, age, tumor proximity to the liver capsule, tumor diameter, microsphere size, previous TACE counts, portal vein tumor thrombus, etc.). In particular, there was a significant interaction between Child-Pugh classification and dilution strategy (P=0.038), suggesting that high dilutions were more effective in relieving pain in Child-Pugh B patients than in Child-Pugh A patients.

[0033] Based on the above findings, this invention provides an individualized selection scheme: for patients with tumors close to the liver capsule, Child-Pugh B grade, or poorly vascularized tumors, a high dilution factor of 50-100 times is selected to enhance analgesia and protect liver function; for patients with subsegmental superselective catheterization or well-vascularized tumors, a dilution factor of 30-50 times is selected to simplify the procedure while ensuring embolization effectiveness. This individualized strategy further improves the precision of clinical application and patient benefit.

[0034] Furthermore, a dilution factor of 50-100 times showed better results in pain control (median highest VAS score of 0 at 72 hours post-operation) and can be considered a more preferred implementation method.

[0035] IV. It does not increase the risk of liver and kidney damage and has good safety. This invention does not increase liver or kidney toxicity with increasing dilution ratio. This is especially important for most patients with hepatocellular carcinoma who also have underlying cirrhosis.

[0036] V. It is easy to operate, low in cost, and easy to promote in clinical practice; This invention only requires adjusting the volume of the microsphere suspension, without adding special equipment, expensive consumables, or changing the existing DEB-TACE operating procedure. The preparation steps (removing the storage solution, loading the drug, allowing it to stand, preparing the dilution medium, diluting to the target multiple, and shaking to mix) do not introduce additional technical complexity. This approach achieves a significant analgesic and synergistic effect at extremely low implementation costs and has good clinical application value.

[0037] In summary, this invention, by increasing the dilution factor of the microsphere suspension to 30-100 times, reveals for the first time that chemical stimulation is a source of pain independent of ischemia and achieves source analgesia accordingly. It has achieved unexpected technical effects such as a significant reduction in the incidence of severe pain and a significant increase in the objective relief rate. At the same time, it provides individualized selection options, maintains good safety, and is simple to operate and low in cost. Attached Figure Description

[0038] Figure 1 The flowchart schematically illustrates a method for preparing a drug-eluting microsphere suspension according to one embodiment of the present invention. Detailed Implementation

[0039] The invention will now be discussed with reference to exemplary embodiments. It should be understood that the described embodiments are merely intended to enable those skilled in the art to better understand and thus implement the invention, and are not intended to imply any limitation on the scope of the invention.

[0040] As used herein, the term "comprising" and its variations are to be interpreted as open-ended terms meaning "including but not limited to". The term "based on" is to be interpreted as "at least partially based on". The terms "one embodiment" and "an embodiment" are to be interpreted as "at least one embodiment".

[0041] Figure 1 The flowchart schematically illustrates a method for preparing a drug-eluting microsphere suspension according to one embodiment of the present invention. Figure 1 As shown, in this embodiment, the method for preparing the drug-eluting microsphere suspension includes the following steps: S1. Remove the storage solution from the drug-eluting microspheres to obtain a microsphere precipitate; S2. Add a chemotherapy drug solution to the microsphere precipitate to load the drug into the microspheres; S3. Mix physiological saline and non-ionic contrast agent at a volume ratio of 1.5:1 to prepare a dilution medium; S4. Add the dilution medium prepared in step S3 to the microspheres after the drug has been loaded in step S2, so that the total suspension volume reaches a preset multiple of the microsphere precipitation volume, and obtain a microsphere suspension. S5. Shake the microsphere suspension obtained in step S4 to mix it well.

[0042] Furthermore, according to one embodiment of the present invention, the total suspension volume is 30 to 100 times the precipitate volume of the microspheres.

[0043] Furthermore, according to one embodiment of the present invention, the chemotherapeutic drug is a positively charged chemotherapeutic drug capable of being loaded onto drug-eluting microspheres via an ion exchange mechanism. For example, epirubicin 40 mg or an equivalent dose of other anthracyclines.

[0044] In this embodiment, the chemotherapy drug is one or more of anthracyclines, irinotecan, gemcitabine, or oxaliplatin.

[0045] Furthermore, according to one embodiment of the present invention, the drug-eluting microspheres are drug-loaded microspheres with a particle size of 40 μm or more. Preferably, the particle size of the drug-loaded microspheres is 100-1200 μm; for example, CalliSphere™, DC Bead™ or other commercially available drug-loaded microspheres, with particle sizes selectable from 100-300 μm, 300-500 μm or 500-700 μm.

[0046] Furthermore, according to one embodiment of the present invention, the process of loading the drug into the microspheres is as follows: after adding the chemotherapy drug solution to the microsphere precipitate, the mixture is shaken and allowed to stand for a sufficient time to fully load the drug into the microspheres (e.g., let it stand for 30 minutes).

[0047] Furthermore, according to one embodiment of the present invention, determining the total suspension volume based on preset conditions such as tumor anatomical location, liver function grade, cannulation selectivity, and tumor blood supply characteristics includes: When the preset conditions are: cannulation selectivity is subsegmental superselectivity and / or tumor blood supply is rich blood supply, the total suspension volume is 30 to 50 times the microsphere precipitation volume; When the preset conditions are: the tumor is close to the liver capsule, the liver function is Child-Pugh B, and / or the tumor blood supply is poor, the total suspension volume is 50 to 100 times the microsphere precipitation volume.

[0048] Furthermore, to achieve the above objectives, the present invention also provides a drug-eluting microsphere suspension, which is prepared by the above-described drug-eluting microsphere suspension preparation method.

[0049] Furthermore, to achieve the above objectives, the present invention also provides the use of the above-mentioned drug-eluting microsphere suspension in the preparation of a medicament for relieving pain after transarterial chemoembolization of drug-eluting microspheres.

[0050] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings, embodiments, and comparative examples. It should be understood that the specific embodiments described herein are merely one preferred embodiment of the invention and are only used to explain the invention. They do not limit the scope of protection of the invention. All other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0051] Example 1 (30-fold dilution) Methods for preparing drug-eluting microsphere suspensions include: Take 1 mL of CalliSphere™ drug-eluting microspheres (particle size 100-300 μm), completely remove the stock solution, and obtain a microsphere precipitate. Add epirubicin solution (40 mg) to the microsphere precipitate, gently vortex to mix, and let stand for 30 minutes to allow the drug to be loaded into the microspheres. Prepare a dilution medium by mixing physiological saline and a non-ionic contrast agent at a volume ratio of 1.5:1. Add the dilution medium to the drug-loaded microspheres to achieve a total suspension volume of 30 mL (30-fold dilution), obtaining a microsphere suspension. Vortex to mix immediately before injection and intermittently during injection.

[0052] DEB-TACE was performed on a 62-year-old female patient with hepatocellular carcinoma, presenting with a single small tumor measuring 2.5 cm in diameter. Due to the tumor's proximity to the gallbladder and the high risk of local ablation, the patient refused surgical resection and TACE was chosen. The tumor was not located near the liver capsule, was Child-Pugh A, allowing for subsegmental superselective cannulation, and was poorly vascularized. Subsegmental superselective cannulation was performed via femoral artery puncture to the tumor's feeding artery, and the prepared microsphere suspension was slowly injected until near-stasis was reached.

[0053] Results: The highest VAS score within 72 hours post-surgery was 3, requiring only one non-opioid analgesic (flurbiprofen 50mg). A follow-up examination one month post-surgery showed partial remission (PR). Liver function indicators showed no significant abnormalities.

[0054] Example 2 (60-fold dilution) Methods for preparing drug-eluting microsphere suspensions include: Take 1 mL of CalliSphere™ drug-eluting microspheres (300-500 μm particle size), completely remove the stock solution, and obtain a microsphere precipitate. Add epirubicin solution (40 mg) to the microsphere precipitate, gently vortex to mix, and let stand for 30 minutes to allow the drug to be loaded into the microspheres. Prepare a dilution medium by mixing physiological saline and a non-ionic contrast agent at a volume ratio of 1.5:1. Add the dilution medium to the drug-loaded microspheres to achieve a total suspension volume of 60 mL (60-fold dilution), obtaining a microsphere suspension. Vortex to mix immediately before injection and intermittently during injection.

[0055] DEB-TACE was performed on a 58-year-old male patient with hepatocellular carcinoma, a single tumor with a maximum diameter of 5.5 cm, located not close to the liver capsule, Child-Pugh A, allowing for superselective cannulation, and the tumor was highly vascularized. The procedure was performed via femoral artery puncture, with superselective cannulation into the tumor's feeding artery, and the prepared microsphere suspension was slowly injected until near-stasis was reached.

[0056] Results: The highest VAS score within 72 hours post-surgery was 2, requiring no analgesics. A follow-up examination one month post-surgery showed complete tumor remission (CR). Liver function indicators showed no significant abnormalities.

[0057] Example 3 (100-fold dilution) Methods for preparing drug-eluting microsphere suspensions include: Take 1 mL of DC Bead™ drug-eluting microspheres (300-500 μm in diameter), completely remove the stock solution, and obtain a microsphere precipitate. Add epirubicin solution (40 mg) to the microsphere precipitate, gently vortex to mix, and let stand for 30 minutes to allow the drug to be loaded into the microspheres. Prepare a dilution medium by mixing physiological saline and a non-ionic contrast agent at a volume ratio of 1.5:1. Add the dilution medium to the drug-loaded microspheres to achieve a total suspension volume of 100 mL (100-fold dilution), obtaining a microsphere suspension. Vortex to mix immediately before injection and intermittently during injection.

[0058] DEB-TACE was performed on the patient using the microsphere suspension prepared above. Specifically, the patient was a 55-year-old male with hepatocellular carcinoma, presenting with multiple large tumors (3 in total), the largest measuring 6.2 cm in diameter. Two of the tumors were located close to the liver capsule. He was a Child-Pugh B patient, and the tumors were highly vascularized. A femoral artery puncture was performed, and a superselective catheter was inserted into the tumor-feeding artery. The prepared microsphere suspension was slowly injected until near-stasis was reached.

[0059] Results: The highest VAS score within 72 hours post-surgery was 1, requiring no analgesics. A follow-up examination one month post-surgery showed complete remission (CR) in all three tumors. Liver function indicators showed no significant abnormalities. Example 4

[0060] Large-scale clinical efficacy validation of microsphere suspensions prepared by the drug-eluting microsphere suspension preparation method includes: 1. Research subjects and grouping A total of 362 hepatocellular carcinoma patients who received DEB-TACE were included and divided into three groups according to the dilution factor of the microsphere suspension: Group A (conventional dilution group, 5-10 times): 103 cases Group B (30-50 times dilution group): 127 cases Group C (>50-fold dilution group, actually 50-100-fold): 132 cases The three groups of patients were comparable in terms of gender, age, tumor characteristics (maximum tumor diameter, number of tumors, Child-Pugh grade, incidence of portal vein tumor thrombus), and procedural characteristics (previous TACE number, proportion of tumors close to the liver capsule, subsegment superselective cannulation rate, microsphere size, injected microsphere volume, and intraoperative lidocaine use rate). (Statistical analysis showed no significant differences between the groups, P>0.05).

[0061] 2. Preparation method Each group was prepared according to the following steps: the microsphere storage solution was completely aspirated to obtain microsphere precipitate; epirubicin solution (40 mg) was added to the microsphere precipitate, gently shaken to mix, and allowed to stand for 30 minutes; physiological saline and non-ionic contrast agent were mixed at a volume ratio of 1.5:1 to prepare a dilution medium; the dilution medium was added to the drug-loaded microspheres and adjusted to the target dilution factor (Group A: 5-10 times; Group B: 30-50 times; Group C: 50-100 times); and the mixture was shaken to mix immediately before injection.

[0062] 3. Postoperative pain outcome Within 72 hours post-surgery, the highest Visual Analogue Scale (VAS) score decreased in a stepwise manner with increasing dilution factor. Group A: Median 6.0 points; Group B: Median 4.0 points; Group C: Median 0.0 (P<0.001 for comparison among the three groups); Incidence of moderate pain (VAS≥4): Group A: 77.7%; Group B: 56.7%; Group C: 28.8%; Incidence of severe pain (VAS ≥ 7 points): Group A: 48.5%; Group B: 10.2%; Group C: 6.8%; Spearman correlation analysis showed a significant negative correlation between dilution factor and pain intensity. (P<0.001).

[0063] 4. Safety Results Within 3 days post-surgery, there were no statistically significant differences in the changes of liver function indicators (ALT, AST, ALB, TBIL) and kidney function indicators (Cr, BUN) from baseline among the three groups (all P>0.05), indicating that the high-dilution strategy did not increase the risk of liver and kidney damage.

[0064] 5. Short-term tumor response results Objective response rate (ORR) was assessed according to mRECIST criteria 1-3 months post-surgery: Group A: 40.8%; Group B: 56.7%; Group C: 58.3%; The differences between group A and group B, and between group A and group C were statistically significant (P<0.05), indicating that the tumor response in the high-dilution group was significantly better than that in the conventional dilution group.

[0065] 6. Results of multivariate analysis Compared with the conventional dilution group (Group A), the adjusted odds ratios (ORs) for severe pain in Group B and Group C were 0.12 and 0.07, respectively (P<0.001), indicating that high dilution is an independent protective factor against severe pain.

[0066] 7. Subgroup Analysis Results High-dilution (Group C) showed consistent analgesic efficacy across different clinical subgroups (gender, age, tumor proximity to the liver capsule, maximum tumor diameter, injected microsphere volume, microsphere particle size, previous TACE count, portal vein tumor thrombus, etc.). Interaction analysis revealed a significant interaction between Child-Pugh classification and dilution strategy (P=0.038), suggesting that high-dilution is more effective in relieving pain in Child-Pugh B patients than in Child-Pugh A patients.

[0067] Comparative Example 1 (conventional 8-fold dilution) Methods for preparing drug-eluting microsphere suspensions include: Take 1 mL of CalliSphere™ drug-eluting microspheres (particle size 300-500 μm) and prepare them according to standard methods: after removing the stock solution, add 40 mg of epirubicin, add physiological saline and contrast agent mixture to make the total suspension volume reach 8 mL (dilution factor 8 times), and shake to mix.

[0068] DEB-TACE was performed on the patient using the microsphere suspension prepared above. Specifically, the patient was a 60-year-old male with hepatocellular carcinoma, a single tumor with a maximum diameter of 4.5 cm, centrally located and not close to the liver capsule, Child-Pugh A, allowing for superselective cannulation, and the tumor was highly vascularized. The procedure was the same as in Example 1.

[0069] Results: The highest VAS score within 72 hours postoperatively was 7. The patient required the use of opioid analgesics (pethidine 50mg intramuscular injection) due to severe pain. One month postoperatively, a follow-up examination showed partial remission (PR). A transient increase in liver function indicators occurred (ALT increased by 35 U / L from baseline).

[0070] Comparative Example 2 (28-fold dilution) Methods for preparing drug-eluting microsphere suspensions include: Take 1 mL of CalliSphere™ drug-eluting microspheres (particle size 100-300 μm), completely remove the stock solution, and obtain a microsphere precipitate. Add epirubicin solution (40 mg) to the microsphere precipitate, gently vortex to mix, and let stand for 30 minutes to allow the drug to be loaded into the microspheres. Prepare a dilution medium by mixing physiological saline and a non-ionic contrast agent at a volume ratio of 1.5:1. Add the dilution medium to the drug-loaded microspheres to achieve a total suspension volume of 28 mL (28-fold dilution), obtaining the microsphere suspension. Vortex immediately before injection and mix intermittently during injection.

[0071] DEB-TACE was performed on a 63-year-old female patient with hepatocellular carcinoma, presenting with a single small tumor measuring 2.4 cm in diameter. Due to the tumor's proximity to the inferior vena cava, local ablation posed a high risk, and the patient refused surgical resection; therefore, TACE was chosen. The tumor was not adjacent to the liver capsule, was Child-Pugh A, allowing for subsegmental superselective cannulation, and was poorly vascularized. Subsegmental superselective cannulation was performed via femoral artery puncture to the tumor's feeding artery, and the prepared microsphere suspension was slowly injected until near-stasis was reached.

[0072] Results: The highest VAS score within 72 hours postoperatively was 4, requiring the use of non-opioid analgesics (flurbiprofen 50mg). A follow-up examination one month postoperatively showed the tumor to be stable (SD). Liver function indicators showed no significant abnormalities.

[0073] Comparative Example 3 (105-fold dilution) Methods for preparing drug-eluting microsphere suspensions include: Take 1 mL of DC Bead™ drug-eluting microspheres (300-500 μm in diameter), completely remove the stock solution, and obtain a microsphere precipitate. Add epirubicin solution (40 mg) to the microsphere precipitate, gently vortex to mix, and let stand for 30 minutes to allow the drug to be loaded into the microspheres. Prepare a dilution medium by mixing physiological saline and a non-ionic contrast agent at a volume ratio of 1.5:1. Add the dilution medium to the drug-loaded microspheres to achieve a total suspension volume of 105 mL (105-fold dilution), obtaining the microsphere suspension. Vortex immediately before injection and mix intermittently during injection.

[0074] DEB-TACE was performed on the patient using the microsphere suspension prepared above. Specifically, the patient was a 56-year-old male with hepatocellular carcinoma, presenting with multiple large tumors (3 in total), the largest measuring 6.0 cm in diameter. Two of the tumors were located close to the liver capsule. The patient was a Child-Pugh B patient, and the tumors were highly vascularized. A femoral artery puncture was performed, and a superselective catheter was inserted into the tumor-feeding artery. The prepared microsphere suspension was slowly injected until near-stasis was reached.

[0075] Results: The highest VAS score within 72 hours postoperatively was 1, requiring no analgesia. One month postoperatively, all three tumors achieved complete remission (CR). A transient, mild increase in renal function indicators occurred (Cr increased by 12 μmol / L from baseline, returning to normal within 3 days postoperatively). No significant abnormalities were observed in liver function indicators.

[0076] According to the above-described solution of the present invention, compared with the conventional solution, the present invention has the following beneficial effects, which can be confirmed by the above embodiments and comparative examples.

[0077] I. Significantly reduces severe postoperative pain, achieving pain relief at the source; Traditional DEB-TACE microsphere suspensions are typically diluted 5-10 times, resulting in a postoperative severe pain incidence (Visual Analogue Scale score ≥7) as high as 48.5%, often requiring patients to rely on opioid analgesia. This invention increases the microsphere suspension dilution factor to 30-100 times, achieving high dispersion of the microspheres in the bloodstream and significantly reducing the peak concentration of local chemotherapy drugs. This directly reduces the chemical stimulation of the blood vessel wall and surrounding tissues, intervening at the source of pain.

[0078] Clinical validation data from Example 4 showed that with conventional dilution (5-10 times), the median VAS score at 72 hours post-surgery was 6.0, and the incidence of severe pain was 48.5%; with dilutions of 30-50 times, the median VAS score decreased to 4.0, and the incidence of severe pain decreased to 10.2%; with dilutions of 50-100 times, the median VAS score further decreased to 0.0, and the incidence of severe pain decreased to 6.8%. The dilution factor was significantly negatively correlated with pain intensity. (and shows a clear step-like downward trend).

[0079] The above results show that the present invention reduces the incidence of severe postoperative pain by 86% (from 48.5% to 6.8%), and the effect increases with the dilution factor, achieving a technological breakthrough in active analgesia from the source of chemical stimulation.

[0080] Second, it achieves a synergistic effect of pain reduction and increased efficacy, breaking with traditional perceptions; The antitumor effect of chemotherapy drugs is usually positively correlated with their local concentration. Conventionally, increasing the dilution factor (reducing the local drug concentration) is expected to weaken the antitumor efficacy. However, this invention unexpectedly discovered that high dilutions, while significantly reducing pain, actually increased the objective response rate to tumor remission.

[0081] Data from Example 4 showed that the objective response rate was 40.8% in the conventional dilution group, increased to 56.7% in the 30-50 fold dilution group, and further increased to 58.3% in the 50-100 fold dilution group. The relative improvement of the high-fold dilution group compared to the conventional dilution group was 39%-43% (P<0.05). Comparative Example 1 (conventional dilution 8-fold) showed only partial remission after surgery, while Example 2 (60-fold dilution) or Example 3 (100-fold dilution) showed complete remission after surgery.

[0082] The mechanism behind this counterintuitive effect lies in the fact that high-level dilution allows for more uniform and distal distribution of microspheres in the bloodstream, improving the embolic integrity of the tumor-feeding arteries and thus enhancing the antitumor effect without relying on higher drug doses. This invention breaks the technical prejudice that dilution reducing local concentration inevitably weakens efficacy, achieving a synergistic effect of pain relief and therapeutic enhancement.

[0083] Third, we provide individualized dilution factor selection options to optimize benefits for different groups of people; This invention further provides a differentiated dilution selection strategy based on patient clinical characteristics. Subgroup analysis showed that high dilutions (50-100 times) had consistent analgesic effects across different clinical subgroups (gender, age, tumor proximity to the liver capsule, tumor diameter, microsphere size, previous TACE counts, portal vein tumor thrombus, etc.). In particular, there was a significant interaction between Child-Pugh classification and dilution strategy (P=0.038), suggesting that high dilutions were more effective in relieving pain in Child-Pugh B patients than in Child-Pugh A patients.

[0084] Based on the above findings, this invention provides an individualized selection scheme: for patients with tumors close to the liver capsule, Child-Pugh B grade, or poorly vascularized tumors, a high dilution factor of 50-100 times is selected to enhance analgesia and protect liver function; for patients with subsegmentally superselective catheterization or well-vascularized tumors, a dilution factor of 30-50 times is selected to simplify the procedure while ensuring embolization effectiveness. This individualized strategy further improves the precision of clinical application and patient benefit.

[0085] IV. It does not increase the risk of liver and kidney damage and has good safety. Safety data from Example 4 showed that within 3 days post-surgery, there were no significant differences (P>0.05) in liver function indicators (ALT, AST, ALB, TBIL) and kidney function indicators (Cr, BUN) from baseline between the high-dilution groups (30-50 times, 50-100 times) and the conventional dilution groups, indicating that the present invention did not increase liver or kidney toxicity with increased dilution. This is particularly important for most hepatocellular carcinoma patients with underlying cirrhosis.

[0086] V. It is easy to operate, low in cost, and easy to promote in clinical practice; This invention only requires adjusting the volume of the microsphere suspension, without adding special equipment, expensive consumables, or changing the existing DEB-TACE operating procedure. The preparation steps (removing the storage solution, loading the drug, allowing it to stand, preparing the dilution medium, diluting to the target multiple, and shaking to mix) do not introduce additional technical complexity. This approach achieves a significant analgesic and synergistic effect at extremely low implementation costs and has good clinical application value.

[0087] VI. Boundary Comparison Scale Verification: The Critical Significance of the 30-100x Range To verify the criticality of the 30-100 times dilution range of the present invention, boundary comparative example 2 (28 times dilution) and comparative example 3 (105 times dilution) were set.

[0088] Comparative Example 2 (28-fold dilution) showed that when the dilution factor was slightly below 30-fold, the postoperative VAS score was 4, significantly worse than Example 1 (30-fold, VAS score 3); the tumor response was only stable disease (SD), while Example 1 achieved partial remission (PR). This indicates that 30-fold is a critical threshold for pain control and tumor response, below which the effect decreases significantly.

[0089] Comparative Example 3 (105-fold dilution) showed that when the dilution factor was slightly higher than 100-fold, the postoperative VAS score (1 point) and tumor response (CR) were not improved compared with Example 3 (100-fold, VAS score of 1 point, CR), and a transient mild increase in renal function indicators was observed. This suggests that further increasing the dilution factor does not bring additional analgesia or therapeutic benefit, but rather increases contrast agent load and renal function risk. Therefore, 100-fold is the upper limit of safety and efficacy.

[0090] The above boundary comparison further confirms that the 30-100 times dilution range selected in this invention has a clear critical significance and unexpected technical effects.

[0091] In summary, this invention, by increasing the dilution factor of the microsphere suspension to 30-100 times, reveals for the first time that chemical stimulation is a source of pain independent of ischemia and achieves source analgesia accordingly. It has achieved unexpected technical effects such as reducing the incidence of severe pain by 86% and increasing the objective relief rate by 39%-43%. At the same time, it provides individualized selection options, maintains good safety, and is simple to operate and low in cost.

[0092] The above description is merely a preferred embodiment of this application and an explanation of the technical principles employed. Those skilled in the art should understand that the scope of the invention involved in this application is not limited to technical solutions formed by specific combinations of the above-described technical features, but should also cover other technical solutions formed by arbitrary combinations of the above-described technical features or their equivalents without departing from the inventive concept. For example, technical solutions formed by substituting the above-described features with (but not limited to) technical features with similar functions disclosed in this application.

[0093] It should be understood that the sequence number of each step in the invention and its embodiments does not absolutely imply the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present invention.

Claims

1. A method for preparing a drug-eluting microsphere suspension, characterized in that, Includes the following steps: S1. Remove the storage solution from the drug-eluting microspheres to obtain a microsphere precipitate; S2. Add a chemotherapy drug solution to the microsphere precipitate to load the drug into the microspheres; S3. Mix physiological saline and non-ionic contrast agent at a volume ratio of 1.5:1 to prepare a dilution medium; S4. Add the dilution medium prepared in step S3 to the microspheres after the drug has been loaded in step S2, so that the total suspension volume reaches a preset multiple of the microsphere precipitation volume, and obtain a microsphere suspension. S5. Shake the microsphere suspension obtained in step S4 to mix it well.

2. The method for preparing drug-eluting microsphere suspension according to claim 1, characterized in that, The total suspension volume is 30 to 100 times the volume of the microsphere precipitate.

3. The method for preparing drug-eluting microsphere suspension according to claim 1, characterized in that, The chemotherapy drug is a positively charged chemotherapy drug that can be loaded onto drug-eluting microspheres via an ion exchange mechanism.

4. The method for preparing drug-eluting microsphere suspension according to claim 1, characterized in that, The chemotherapy drug is one or more of anthracyclines, irinotecan, gemcitabine, or oxaliplatin.

5. The method for preparing drug-eluting microsphere suspension according to claim 1, characterized in that, The drug-eluting microspheres are drug-loaded microspheres with a particle size of 40 μm or larger.

6. The method for preparing drug-eluting microsphere suspension according to claim 5, characterized in that, The particle size of the drug-loaded microspheres is 100-1200 μm.

7. The method of claim 6, wherein the drug eluting microsphere suspension is prepared by, The particle size of the drug-loaded microspheres is 100-300μm, 300-500μm, or 500-700μm.

8. The method of suspending a drug eluting microsphere of claim 1, wherein, The process of loading the drug into the microspheres involves adding the chemotherapy drug solution to the microspheres, precipitating the precipitate, shaking to mix, and allowing it to stand to ensure that the drug is fully loaded into the microspheres.

9. The method of claim 2, wherein the drug eluting microsphere suspension is prepared by, The total suspension volume is determined based on pre-defined conditions including tumor anatomical location, liver function classification, cannulation selectivity, and tumor blood supply characteristics, including: When the preset conditions are: cannulation selectivity is subsegmental superselectivity and / or tumor blood supply is rich blood supply, the total suspension volume is 30 to 50 times the microsphere precipitation volume; When the preset conditions are: the tumor is close to the liver capsule, the liver function is Child-Pugh B, and / or the tumor blood supply is poor, the total suspension volume is 50 to 100 times the microsphere precipitation volume.

10. A suspension of drug eluting microspheres characterized in that, It is prepared by the drug-eluting microsphere suspension preparation method according to any one of claims 1-9.

11. The use of the drug-eluting microsphere suspension according to claim 10 in the preparation of a medicament for relieving pain after transarterial chemoembolization of drug-eluting microspheres.

Images