Lidocaine hydrochloride preparations with ionic and non-ionic polymers assessed at standard and increased skin surface temperatures

Abstract

AbstractIn this study, the release of lidocaine hydrochloride was assessed considering the use of both the ionic and the non-ionic polymeric carrier at temperatures of 22°C, 32°C, and 42°C; temperature of 32°C was chosen as the reference surface body temperature. The obtained release rates and respective amounts of lidocaine hydrochloride loaded both to methylcellulose beads and polyacrylic acid beads were compared with respective viscosity, pH and conductivity of the studied systems. The release of lidocaine hydrochloride from the methylcellulose system is influenced by temperature; with the increase of temperature the release rate decreases whereas the viscosity increases. In the polyacrylic acid system, release rates are lower, however, in the first stage they are slightly increasing with the increase of temperature. The final amount of released drug after 24 h increases with the temperature of the release process environment, and it is higher in case of a methylcellulose system. The maximum differences between the released amounts for methylcellulose were in the range of 15 %, whereas in case of polyacrylic acid, the difference was approximately 12 %. Thus, this research is important for patients with differentiated skin surface temperature conditions to whom a local analgesic is to be applied.