Enhanced bioavailability of L-carnitine after painless intradermal delivery vs. oral administration in rats

Abstract

Purpose: In vitro and in vivo permeation studies were conducted to evaluate the characteristic of percutaneous administration of high hydrophilic drug L-carnitine (LC) by Functional MicroArray (FMA) painless intradermal delivery system.

Methods: In vitro study was designed to assess the effects of various skins, donor concentration and hydrogels from different carbomer derivatives on the release of LC in a Franz-type diffusion cell. The LC gel patches with carbomer 980 P were prepared and successfully applied to pharmacokinetic study of SD rats with and without FMA. Intravenous injection and oral administration were performed to support pharmacokinetic calculations and comparison of bioavailability.

Results: Enhanced delivery of LC using FMA was achieved in skin of different species in vitro studies. The 750 mg LC gel patches were applied to rats over 6 h, and approximately 27% of loaded dose was transported into rat. A 2.8-fold enhancement of absolute bioavailability for LC with FMA intradermal delivery system was observed compared with oral LC administration in vivo study.

Conclusions: Both in vitro and in vivo studies demonstrated that the FMA intradermal delivery system can enhance the delivery and bioavailability of LC.