Investigation and optimization of formulation factors of a hydrogel network based on kappa carrageenan–pregelatinized starch blend using an experimental design

In the present work we evaluate the results of a combination of two hydrophilic polymers such as kappa carrageenan (κ-Carr) and pregelatinized starch (PGS) in the improvement of the properties of a gel blend containing miconazole. A design of experiments and in particular a Box–Behnken design was applied for the optimization and assessment of the effects of three independent factors (amounts of κ-Carr, glycerol and polysorbate 80) on the bioadhesive properties and drug release kinetics of kappa carrageenan–pregelatinized starch blend. The in-vitro release study revealed that the most formulations showed extended release profiles of miconazole over 2 h. The majority of the matrices that contained 0.3% of κ-Carr eroded prematurely. From the obtained results it was noticed that the gel matrices released drug by diffusion. It was also shown that the addition of κ-Carr to PGS-based gel improves its bioadhesive characteristics and the extended drug release. The optimized gel deduced from the experimental design was characterized and its properties such as swelling, bioadhesion and release kinetics were evaluated.