Development and characterization of mucoadhesive patches of salbutamol sulfate for unidirectional buccal drug delivery.

Buccal patches of salbutamol sulfate were prepared using five different water soluble polymers in various proportions and combinations using PEG-400/PG as plasticizers. A 32 full factorial design was used to design the experiments for each polymer combination. Patches were laminated on one side with a water impermeable backing layer for unidirectional drug release. The thickness of medicated patches ranged between 0.2 and 0.4 mm and showed an increase in mass whenever PEG-400 was used as plasticizer. The surface pH of all patches approached neutral. Eight formulations which had shown high folding endurance (> 300) were selected for evaluation. Patches prepared with PEG-400 showed a high swelling index. The residence time of the tested patches ranged between 105 and 130 min. Formulations A10, A32, B10 and B32 fitted the Higuchi model best, whereas formulations A19 and B19 showed super case II transport drug release. Stability studies indicated that there was no change in the chemical and physical characteristics during the test period of 6 months.