The purpose of the research work was to optimize and formulate promethazine theoclate fast dissolving tablets that offer a suitable approach for the treatment and management of nausea and vomiting. The solubility of promethazine theoclate was increased by preparing its fast dissolving tablets containing β-cyclodextrin, crospovidone, and thymol using direct compression method. A 3-3 full factorial design was used to investigate the combined influence of three independent variables - amount of thymol, crospovidone and β-cyclodextrin on disintegration time, percentage friability and percent drug release after 5 min. The optimization study, involving multiple regression analysis, reveals that optimum amounts of thymol, crospovidone and β-cyclodextrin gave a rapidly disintegrating/dissolving tablet. A checkpoint batch was also prepared to verify the validity of the evolved mathematical model. The optimized tablet should be prepared with an optimum amount of β-cyclodextrin (19.20 mg), thymol (12.26 mg) and crospovidone (2.44 mg) which disintegrated in the 30 seconds, with a friability of 0.60 % and 81 % of drug release in 5 min. The optimized approach aided both the formulation of fast dissolving theoclate tablets and the understanding of the effect of formulation processing variables on the development of formulation.
