Study on the Development and Evaluation of a Novel Modified Release Pellet-based System for the Delivery of Desloratadine and Pseudoephedrine Hydrochloride

Modified-release multiple unit dosage form (MRMUD) of desloratadine and pseudoephedrine
hydrochloride with different release profiles were prepared. The MRMUD system consisting the
immediate-release pellets of desloratadine and sustained release pellets of pseudoephedrine
hydrochloride was formulated by using solution layering technique. A 32 full-factorial design was
employed to optimize the sustained release formulation where in polymer ratio (Ethyl cellulose:
hydroxyl propyl methyl cellulose) (X1) and % polymer coating (X2) were taken as independent
variables and amount of drug release, in 0.1N HCl (Y1), after 10 hrs (Y2) were taken as the
dependent variables. Optimization studies were carried out using the Design Expert Software.
Formulations were evaluated for in vitro release studies; the release data were evaluated by the
model dependent (curve fitting) method using the PCP Disso software. The in vitro drug release
followed Hixson-Crowell model and the drug release mechanism was found to be anomalous or nonfickian
type. It was found that proper combination of ethyl cellulose and hydroxy propyl methyl
cellulose polymer, % polymer coating and process parameters could provide sustained release of
pseudoephedrine hydrochloride for a period of 12 hrs. The statistical approach for formulation
optimization is a useful tool, particularly in simultaneously evaluating several variables. The observed
responses were in close agreement with the predicted values of the optimized formulations,
demonstrating the feasibility of the optimization procedure in developing sustained release
formulation.