Design and Development of Mouth Dissolving Film of Promethazine Hydrochloride

The objective of this research was to formulate a mouth dissolving film (MDF) of Promethazine Hydrochloride, aimed at improving its oral bioavailability and providing a quicker onset of action for treating allergic conditions. As a member of BCS Class I, Promethazine Hydrochloride has an oral bioavailability of only about 28% due to first-pass metabolism. To mask its bitter taste, a drug inclusion complex with β-cyclodextrin was created. The MDF was prepared using the solvent casting method and included sodium starch glycolate (as disintegrating agent), mannitol (as a sweetener), citric acid (to stimulate saliva), HPMC E-15 (as a film-forming agent), β-cyclodextrin (for taste masking), PEG-400 (as a plasticizer), peppermint oil (as a flavouring agent), and royal blue colour (as a colouring agent). Optimization was carried out using a three-level (3²) full factorial design, with the concentrations of the disintegrating agent (X2) and polymer (X1) as independent variables. Various parameters were assessed, including weight variation, thickness, folding endurance, surface pH, drug content uniformity, in-vitro disintegration time, in-vitro % drug release, and stability studies. The results indicated that the MDF (F6) achieved an in-vitro drug release of 98.2% and in-vitro disintegration time of 26.56 seconds, suggesting a higher bioavailability and faster onset of action compared to available tablet forms. These findings indicate that mouth dissolving films could be an effective option for treating allergies when rapid action is required.