Lecithin organogels as model carriers of pharmaceuticals

Abstract

Lecithin microemulsion based organogels (MGs) formulated with cellulose derivatives such as hydroxypropylmethyl cellulose (HPMC) and hydroxypropyl cellulose (HPC) were studied as matrices for the transdermal transport of drugs. Lecithin, as well as the cellulose derivatives used, are pharmaceutical-grade compounds. The general properties of these MGs containing drugs such as their stability in various organic solvents and ability to incorporate sizeable amounts of model drugs were investigated. Drugs such as fluconazol and diclofenac diethylammonium were dissolved in the hydrophilic compound of the gel. The passage of the encapsulated drugs from the organogel through a membrane was studied with Franz diffusion cells and the amount of the drug was determined spectroscopically. It was found that large amounts of the drugs could be transported from the organogels through membranes to an acceptor solution depending on the nature of the organogel used and the solvent of the microemulsion. Our results show that MGs formulated with cellulose derivatives can be used as good matrices for transdermal transport of drugs.

Acknowledgements The Greek General Secretariat of Research and Technology and Pharmathen Ltd. financed this work, within the frame of the program ΠABE 97-BE-93.