Fast‑dissolving oral films containing dextromethorphan/phenylephrine for sinusitis treatment: formulation, characterization and optimization

This work uses optimization study to formulate a patient-friendly antitussive fast-dissolving oral film based on phenylephrine hydrochloride (Phen) and dextromethorphan hydrobromide (Dex). The designed films were based on hydroxypropylmethyl cellulose (HPMC) with two grades (E5 and E50) as a film-forming polymer by the solvent-casting method. Polyethylene glycol with two molar masses (400 and 1000) was used as a plasticizer, while aspartame was used as a sweetener and micro- crystalline cellulose intended to act as a disintegrant. To find an optimum formulation, a response surface methodology and a central composite design were employed. The percentage of HPMC E50, and PEG, as a plasticizer, were considered to be the design factors. Film thickness, surface pH, disintegration time, dissolution percent, tensile strength, elongation percent and folding endurance were considered to be the responses. A film with 11.46% E50, 88.54% E5, 25% of two drugs (8.4% of Phen and 16.6% of Dex) and 18.54% plasticizer is designed and prepared as the optimum formulation for Phen/Dex fast- dissolving oral films, with 95% confidence levels.