Preparation and Development of Oral Controlled Release w/o/w Multiple Emulsion of Carbamazepine

The purpose of this work was to formulate a controlled release multiple emulsion of carbamazepine favorable for administration in pediatrics and geriatrics suffering from epilepsy, decreasing the dosing frequency, thereby improving patient compliance and providing a platform for personalized medicine. Two–step emulsification procedure was employed for the formulation using liquid paraffin oil, water, surfactants and hydroxypropyl methylcellulose as the stabilizer. 2(4) full factorial design was applied for the optimization of the formulations consistent with the quality by design approach. The response variables were 1st hour release, 5th hour release, and time for 90% drug release and % entrapment efficiency. The optimized batch formulated with 8% w/w Span 60, 3% w/w Tween 80, 0.5% w/v hydroxypropyl methylcellulose (in internal aqueous phase) and the phase volume ratio of 1:1:2 was found to exhibit entrapment efficiency of >70% and zero order release profile. The similarity factor of 71 was obtained on release profile comparison of the 200mg/10ml optimized batch and the marketed Tegretal XR® 200 mg tablets. Carbamazepine being an autoinducer has high half life during the initiation of therapy which decreases during the course of maintenance therapy which requires the dose to be increased. The release profile of 100mg/5ml emulsion and 200mg/10ml emulsion both sufficed the criteria for >30% drug release in 1st hour and prolonged drug release up to 10 and 12 hours respectively. Hence through this research, personalization of therapy was claimed, to titrate the dosing needs according to the individual requirements during the initiation and maintenance therapy.