MICROEMULSION GEL OF IRBESARTAN: A POTENTIAL TRANSDERMAL DELIVERY SYSTEM

The transdermal delivery route is increasingly being used for drug delivery primarily because the route avoids drawbacks encountered with oral and parenteral routes of drug administration. Irbesartan is an angiotensin II receptor antagonist used clinically to treat hypertension. The objective of the present study was to investigate microemulsion gel as a transdermal delivery system of irbesartan while envisaging drug bioavailability enhancement. The microemulsion based gel of irbesartan was prepared by incorporating optimized microemulsion containing 0.075% w/w of irbesartan into the gelling vehicle. The gelling vehicle was made by dispersing 2% w/w of polycarbophil in distilled water. Irbesartan-loaded microemulsion gel was characterized by droplet size and polydispersity index determinations. Physicochemical properties of irbesartan-loaded microemulsion gels were studied using reported procedures. Diffusion Franz cell was utilized for in-vitro skin permeation while an in-vivo study in rats was by non-compartmental pharmacokinetic model. Activation energy measurement was used to assess the skin permeation mechanism. The droplet size and polydispersity of the microemulsion based gel of irbesartan were in the range of 80 – 82 nm and 1.040 – 1.087, respectively. The in-vitro skin permeation result gave a higher permeability coefficient and steady-state flux when compared with the irbesartan suspension. In the pharmacokinetics study, higher plasma concentration and larger area under the curve were also observed when compared with irbesartan suspension. The in-vitro and in-vivo results suggest that microemulsion gel could be a more potential transdermal drug delivery system of irbesartan than microemulsion.