Preparation And Quality Evaluation Of Lappaconitine Hydrobromide Sustained-Release Injection

Postoperative pain is an acute traumatic pain that occurs immediately after surgery.It is the most common and urgent pain in clinic.Postoperative pain usually lasts for several days.Analgesic treatment based on opioid or non-steroidal anti-inflammatory drugs can cause serious postoperative complications and greatly damage gastrointestinal,respiratory and sensory functions.In recent years,prolonging the duration of drug analgesia and reducing the use of opioid drugs after surgery have gradually become the demand of clinical analgesic drugs,so the application of longacting analgesic sustained release injection in postoperative has become a research hotspot.Lyotropic liquid crystal is a homogeneous mixed system.After contacting with body fluid,amphiphilic liquid crystal materials can form a gel reservoir with lamellar,cubic and hexagonal liquid crystal structures as a sustained release matrix.The formation of lyotropic liquid crystals is mainly due to the interaction between amphiphilic molecules.When the amphiphilic molecules of different concentrations contact with water,the interaction between hydrophilic head groups and hydrophilic tail groups of different proportions in the system leads to the change of the interface curvature of the lipid bilayer of the system,thus forming a gel reservoir with different liquid crystal structures,giving play to different slow-release effects.Lappaconitine(LA)is an alkaloid extracted from the root of Aconitum sinomontanum Nakai,a plant of Ranunculaceae,which is insoluble in water.Its hydrobromide(LAH)is commonly used in clinic.Compared with the existing simple analgesics,its multiple pharmacological effects,such as antipyretic,antiinflammatory,detumescence and local anesthesia,can play a synergistic role in the swelling and pain of wounds caused by postoperative inflammation,and make the body recover to a healthy level smoothly.The non-addictive and analgesic effect of lappaconitine hydrobromide make it have a good application prospect,but the half-life of lappaconitine hydrobromide preparations currently sold in the market is short in vivo,which requires a long time and frequent administration,and the compliance of patients is poor.Therefore,this study prepared the long-acting analgesic lappaconitine hydrobromide lyotropic liquid crystal injection(LAH-LLCI),which can exert the longacting analgesic effect by controlling the slow release of the drug,in order to provide a new strategy for the treatment of postoperative analgesia.The specific research and results are as follows:1.Study on formulation and process of LAH-LLCIThe liquid crystal materials in this study were determined by evaluating the gelling ability of different liquid crystal materials after contacting with phosphate buffer solution,and their mutual solubility with the solvent propylene glycol and the solvent ethanol required in the preparation process.The oil phase,solvent ratio and acid type of the study were determined by the appearance stability of the preparation as the evaluation index.Soybean lecithin was added as the sustained-release material.The final formulation of LAH-LLCI was 2% lappaconitine hydrobromide,70%(glycerol monooleate / soybean lecithin),7.65% castor oil,20% propylene glycol and 0.35%maleic acid.By adjusting the ratio of glyceryl monooleate to soybean lecithin,LAHLLCI with different liquid crystal structure was prepared after hydration.The structure of the liquid crystal formed after hydration was characterized by polarizing microscope and freeze transmission electron microscope.The results showed that when the ratio of glyceryl monooleate to soybean lecithin was 50 : 20,40 : 30,10 : 60,LAH-LLCI prepared after hydration could obtain cubic phase gel reservoir with hexagonal and lamellar liquid crystal structure.In addition,the solvent evaporation method was selected as the preparation method of this preparation,and LAH-LLCI was successfully prepared.This method is simple and time-consuming.2.In vitro study of LAH-LLCIA simple,sensitive and specific HPLC method for the determination of lappaconitine hydrobromide was established,and a reliable method was provided for the determination of the release characteristics of LAH-LLCI in vitro.The in vitro release method of LAH-LLCI was established,the release behavior of LAH-LLCI with different liquid crystal structures after hydration was studied,and the release mechanism of LAH-LLCI with different liquid crystal structures in vitro was clarified by mathematical model fitting.Different LAH-LLCI hydrated to form gel reservoirs with different liquid crystal structures.The in vitro release of LAH-LLCI conformed to the Ritger Peppas model,the release mechanism was Fick diffusion,and the drug release rate was lamellar liquid crystal > cubic liquid crystal > hexagonal liquid crystal.3.LAH-LLCI in vivo evaluation studyThe sustained release effect of LAH-LLCI was evaluated by investigating the drug release behavior of LAH-LLCI in vivo.On the third day,the drug residue in the gel reservoir with hexagonal liquid crystal structure formed after the preparation contacted with body fluid was 0.47%,indicating that the drug could be released continuously in the body for three days.The elimination of LAH-LLCI in vivo showed that after administration,the preparation was initially in a solution state under the skin of rats,and then changed into a gel shape.After 12 hours,the preparation at the administration site was still in a semi-solid block shaped gel repository,and at 21 days,it was a flowing viscous liquid,indicating that LAH-LLCI could be biodegraded and gradually eliminated at the administration site.The pain model of SD rats after back incision was established,and the analgesic efficacy of LAH-LLCI was evaluated in vivo and its safety was investigated.Compared with the rapid release drug delivery group,the onset time of LAH-LLCI with hexagonal liquid crystal structure formed after hydration was not delayed,and the analgesic effect lasted for 3 days.Compared with the untreated group,the wound healing was good,and no abnormality was found in the local tissue observed by pathological section,showing good safety and tolerance.The LAH-LLCI prepared in this study was in a solution state at room temperature.The phase transition occurred in the contact between the drug delivery site and the body fluid,forming a gel reservoir with liquid crystal structure,and the drug was released slowly and continuously.The sustained-release injection can prolong the analgesic time and reduce the times of administration,providing a reference for the follow-up research and design of long-acting sustained-release analgesic injection.