ESTABLISHING AN INVERTEBRATE TEER SCREENING MODEL FOR THE PENETRATION ENHANCERS USING L. terrestris

Many drugs, specifically macromolecules - molecules with low bioavailability and low solubility - are generally not suitable for oral delivery, particularly for protein and peptide drugs. This results in difficulty in delivery of drugs when taking medication, leading to great ineffectiveness. Improving safety efficacy ratio of drugs has been attempted using different methods such as individualizing drug therapy, dose titration, and therapeutic drug monitoring. There are also various routes of doses being developed for a more effective way to deliver drugs, such as dermal, buccal, nasal mucous membrane delivery and so on. Despite new drug delivery method being developed, there are still limitations. Therefore, the penetration enhancers, chemical compounds that facilitate drug penetration into skin more easily are reinforced for decreasing the barrier resistance. The objective of the study was to establish an invertebrate animal model using L. terrestris for screening penetration enhancers for intraoral buccal drug delivery system.

In this study, an electrical potential was induced across the skin of L. terrestris and the change of electrical potential was monitored, while replacing the initial aqueous medium into the solutions dissolved with penetration enhancers such as SDS (Sodium Dodecyl Sulfate), Laurocapram, alcohol and DMSO (dimethylsulphoxide) and L. Menthol. The result showed a highly linear relationship of the decreasing slopes with solution concentrations of all the penetration enhancers examined in the study, with which it demonstrated the feasibility of an appropriate screening model of L. terrestris. Considering their maximum slope comparison, the order of penetration enhancing capability was laurocapram>DMSO>SDS>l-menthol>ethanol. For now, the L. terrestris model suggested these relative orders might be meaningful if the study was performed for screening purposes. More study might be needed to convert the relative capability into more quantitative evaluation for understanding the mechanism of enhancing capability among penetration enhancers.