FORMULATION AND EVALUATION OF TADALAFIL SUBLINGUAL FILM USING 3² FACTORIAL DESIGN

Abstract

Background: Tadalafil is a phosphodiesterase type 5 (PDE5) inhibitor used for the treatment of erectile dysfunction. Conventional oral tablets exhibit delayed onset of action due to hepatic first-pass metabolism and slow dissolution. Sublingual films offer advantages including rapid disintegration in the oral cavity, enhanced bioavailability through sublingual absorption, and convenient administration without water.

Objective: The present study aimed to formulate and optimize sublingual films of Tadalafil using 3² factorial design to achieve rapid disintegration with adequate mechanical properties for the management of erectile dysfunction requiring faster onset of action.

Methods: Sublingual films were prepared by solvent casting technique using HPMC E15 and polyvinyl alcohol (PVA) as film-forming polymers, propylene glycol as plasticizer, and mannitol as sweetener. A 3² full factorial design was employed to study the effect of two independent variables (HPMC E15 and PVA concentrations) on dependent variables including disintegration time and tensile strength. Films were evaluated for mechanical properties, surface pH, drug content, and in-vitro drug release.

Results: FTIR studies confirmed the absence of drug-excipient incompatibility. Preliminary trials established propylene glycol (20% w/w) as the optimal plasticizer and HPMC E15-PVA combination as the optimal polymer system. Among the nine factorial batches, formulation F4 containing HPMC E15 (14 mg) and PVA (4 mg) demonstrated optimal characteristics with disintegration time of 14.66±1.52 seconds, tensile strength of 10.12±0.48 g/cm², folding endurance of 265, and drug release of 92.78±0.75% within 5 minutes. Statistical analysis confirmed the significant effects of both polymers on response variables.