Abstract

ENHANCEMENT OF TOPICAL DRUG DELIVERY BY LIQUID CRYSTALS

Minoo Saxena*, Anil Pethe and Sanjay Boldhane

Abstract

The skin became popular as a potential site for systemic drug delivery because it was thought to (a) avoid the problems of stomach emptying, pH effects, and enzyme deactivation associated with gastrointestinal passage; (b) to avoid hepatic first-pass metabolism; and (c) to enable control of input, as exemplified by termination of delivery through removal of the device. Delivery of solutes through the skin is associated with various difficulties, such as solubilization, hydration, retention or bioadhesiveness, modified reelase and depot formation. Topical and regional delivery has become potential application for antifungal and analgesics. The flux of a drug through the skin is not only dependent on the physicochemical nature of the permeant but also on the nature of the formulation and the vehicle composition. Liquid crystal have potential to alter the flux, which is intermediate state between solid and liquid state. A formulation may alter the properties of the skin and hence enhance or retard the permeation of a drug by increasing or decreasing its diffusivity and/or solubility within the stratum corneum. Liquid crsytasl can be prepared by top-down, bottomup and heat treatment approach. Liquid crystals have an ability to incorporate, solubilize and release a variety of drugs with different physicochemical properties i.e. hydrophilic, lipophilic and amphiphilic drugs and protecting them from physical and enzymatic degradation. It has similarity between structure of cubic phase of lyotropic liquid crystals to physiological lipid membranes i.e. stratum corneum therefore enhance the drug permeation through skin. It provides long-term hydration of the skin.

Keywords: liquid-crystal, topical drug delivery, skin retension, depot-formation, lyotropic liquid crystals.