Formulation, Characterization, and Optimization of Captopril Fast-Dissolving Oral Films

This work aimed to using optimization study to formulate a patient-friendly captopril fast-dissolving oral film with satisfactory disintegration time. Films were made with pullulan and hydroxypropyl methyl cellulose (HPMC) by using the solvent-casting method. Cellulose nanofiber (CNF) was used as a compatibilizer and glycerine was used as a plasticizer. In order to find an optimum formulation, a response surface methodology and a central composite design were employed. The concentration percentages of pullulan and glycerine were considered to be the design factors. Disintegration time, tensile strength, percent elongation at break, and folding endurance were considered to be the responses. The results showed that CNF improved the compatibility and tensile strength of the pullulan and HPMC blend. Also, the rigid nature of CNF reduced the film elongation but the addition of glycerine improved its flexibility. All formulations showed an acceptable uniformity content and dissolution rate. Complete dissolution for all formulations occurred within 2 min. Films with 26% pullulan, 74% HPMC, 1% CNF, and 5% glycerine were reported to be optimum formulations for captopril fast-dissolving oral films, with 95% confidence levels. The in vivo comparison of optimized formulation with a conventional captopril sublingual tablet exhibited significant increase in AUC (~ 62%) and C_max (~ 52%) and a major decrease in T_max (~ 33%). The overall results showed that the captopril FDF is a promising candidate for enhanced in vivo orotransmucosal absorption.