Meitonger injection (trade name) is a long-term local anesthetic analgesic made of menthol and lidocaine. It has been widely used in anesthesia and long-term pain relief in anorectal surgery. As a subcutaneous and tissue infiltration injection application, the analgesic effect is strong and lasting. Clinical control observation shows that the analgesic effect after operation lasts for about 9 days, which is roughly consistent with the wound healing time. No systemic toxic reaction was found, no delayed wound healing was found, and no general analgesics were needed (or less) after operation. But it also has some shortcomings. Injections are too superficial, and excessive local use can lead to edema or superficial necrosis. Because of the use of ethanol solution, irritation is strong, most patients have a temporary "burning tingling sensation".
Menthol is a white strip or columnar crystal, easy to volatilize, insoluble in water, soluble in ethanol, esters and so on. It is difficult to make water-soluble preparations. For a long time, menthol injection used ethanol as a solvent, which has strong irritation to patients, and can not be used in patients allergic to ethanol. Hydroxypropyl beta-cyclodextrin (HP-beta-CD) is a kind of amorphous powder. It has high solubility in water and soluble in alcohol aqueous solution. It has low nephrotoxicity. It can be used in non-intestinal route of drug delivery. It hardly participates in metabolism and does not accumulate in organisms. It forms inclusion complex with drugs and promotes drug release. HP-beta-CD has low surface activity, basically no hemolysis and irritation. It is a kind of medicinal excipient with the least side effects and the best safety.
The solubilization of menthol by HP-beta-CD inclusion significantly increased the solubility of menthol in water, which was conducive to its preparation in aqueous solution. Animal pharmacodynamic experiments showed that menthol HP-beta-CD inclusion hydrate injection had good analgesic effect and irritation, and it was a colorless long-term local analgesic. It has the following characteristics: (1) increasing the water solubility of menthol and reducing its volatilization; (2) using water dosage form to avoid side effects such as ethanol allergy; (3) making the injection safer, less toxic side effects, overcoming edema or tissue necrosis, and making wound healing faster; (4) analgesia time can be adjusted to 4-8 as needed. D; (5) Formulas can be diversified according to demand.
Shandong Binzhou Zhiyuan Biotechnology Co., Ltd. is an innovative and technological company specializing in cyclodextrin and its derivatives. The hydroxypropyl beta-cyclodextrin produced by the company is a kind of medicinal excipient with high safety and no side effects. It is one of the beta-cyclodextrin derivatives which have been thoroughly studied in preparation methods, toxicological experiments and application fields in recent years. It has a wide range of applications in pharmaceutics: 1. It can increase the water solubility of incompatible drugs; 2. It can be used in pharmaceuticals. In order to increase the stability of drugs, improve the bioavailability of drugs; 3, reduce the toxicity and side effects of drugs, and so on. There is room for development of hydroxypropyl beta-cyclodextrin in new drugs such as enzymes, proteins, polypeptides, hormones, and active ingredients of Chinese herbal medicine.