ABSTRACT
In vitro release of propranolol hydrochloride, a commonly used β-adrenergic blocking agent, form various hydrophilic polymeric gels was studied. These included: Methocel®, Avicel®, polyvinyl alcohol, methyl cellulose and gelatin-based systems. Several ingredients, such as ethyl alcohol, dimethylsulphoxide (DMSO) and polyethylene glycol 400 were included in the formulations at various concentration levels for possible enhancement of drug release. The release studies were carried out using a cellulose membrane and hairless mouse skin as the diffusion barriers. The general rank order for the drug release through these membranes was observed to be as follows: Methocel® matrix>Avicel® CL-611 matrix>PVA-gelatin matrix>emulsion base. The inclusion of other ingredients in the formulations had little or no effect in enhancing the drug release. However, when the hairless mouse skin was soaked in DMSO for 1 h prior to use in the diffusion studies, the drug release was increased by 40%. The amount of propranolol hydrochloride released from the Methocel® matrix in 24 h was observed to be well within the therapeutic range, i.e. 0.210.81 mg per litre.
