Microneedle-Mediated Transdermal Delivery of Tizanidine Hydrochloride.

Tizanidine hydrochloride is a skeletal muscle relaxant used for the treatment of spasm, a sudden involuntary muscle contraction leading to pain. The presently available oral dosage form has limitations such as high first pass metabolism resulting in low oral bioavailability. The short half-life necessitates its frequent administration to maintain the required plasma concentration. Transdermal delivery of drug avoids its first pass hepatic metabolism and gives controlled release, making it possible for reduction in dosing frequency. Drug delivery through transdermal route is severely limited by the presence of a tough stratum corneum barrier. A penetration enhancement approach is often necessary to achieve desired plasma concentrations. Microneedles are very short and sharp needles which do not cause pain. Thus, in the present investigation, preparation and evaluation of a transdermal delivery system for tizanidine hydrochloride based on microneedles are described.