Abstract
Due to the limited availability of industrially manufactured products contain-ing local anesthetics for skin application and increased demand for lidocaine containing gel applicable prior to a product containing capsaicin for neuropathic pain treatment, it is necessary to prepare a topical semi-solid preparation containing a local anesthetic in pharmacies. Our aim was to create a mixed system of hydrophilic gel with emulsified drug, using excipients to decrease the lidocaine melting point, thereby creating an eutectic mixture with a high concentration of lidocaine in the oil phase.
Material and methods: Based on bibliographic data, thymol creating a binary eutectic system containing lidocaine has been chosen. After addition of other excipients, an emulsion system was prepared and the drug was stabilized in oil phase by a mixed nonionic emulsifier and carbomer.
For optimal anesthetic effects, the pH value should be adjusted; trometamol has been chosen as a suitable basic reacting excipient. Results and discussion: Based on the addition of different amounts of trometamol, pH values of individual emulgels have been measured and the final composition of lidocaine emulgel has been created.
Conclusion: A recipe for 5 % lidocaine emulgel with pH value of 9,1 has been created, based on gel-forming substance carbomer with an emulsion of the oil phase containing an eutectic mixture of lidocaine and thymol, with the addition of ethanol and propylenglycol, stabilized by a mixed nonionic emulsifier. The advantage is absence of other local anesthetics