Chitosan Gel for Transdermal Delivery of Morphine Hydrochloride

We developed a chitosan (CHI) gel containing alcohols and l-menthol (MEN) as skin permeation enhancers,and succinic acid (SUC) as a cross-linking agent and examined the permeation of morphine hydrochloride (MPH) from the CHI gel into human skin.The solubility of CHI and MEN was measured beforehand in order to create a system saturated with these 2 substances.Solubility varied with the content of ethanol and 1,3-butylene glycol.The saturated CHI gel displayed sufficient elasticity to be applied to a fixed area of skin.The permeation of MPH into the skin from the CHI gel was compared with its permeation into the skin for a polyvinyl alcohol (PVA) gel having a similar composition.Permeation was greater for the CHI gel in the later stages of the experiment.Our CHI gel should thus be useful for the transdermal delivery of MPH.