Electron beam irradiation: a novel technology for the development of transdermal system of isosorbide dinitrate.

The development of a transdermal delivery system for isosorbide dinitrate (ISDN) using electron beam irradiation was studied. The solid state stability of the drug to irradiation was assessed. The drug was dissolved in 2-ethylhexylacrylate (EHA)-acrylic acid (AA) system and this solution was directly irradiated on a backing membrane (Scotchpak1006) at different doses to get transdermal patches. The developed systems were evaluated for residual monomer content, equilibrium weight swelling ratios (EWSR), differential scanning calorimetry (DSC), weight uniformity, thickness uniformity, drug content and content uniformity, peel strength, in vitro release, skin permeation kinetics and skin irritation potential. The developed system possessed excellent adhesive properties. Increase in the irradiation doses did not have a significant effect on the peel strength values. The systems exhibited promising skin permeation kinetics and no skin irritating potential, both of which are important properties for transdermal drug delivery. The ISDN-EHA-AA system developed at an irradiation dose of 50 kGy showed a higher skin permeation profile as compared to an internationally marketed transdermal matrix system of ISDN.

Feasibility of an in vitro microbiological model as an alternative to the rabbit eye model.

Ocular inserts of gentamicin sulfate with polyvinyl alcohol (PVA) 1.5%, 2.0%, and 2.5% and a combination of methyl cellulose 2% and Eudragit NE 30D 30%, 35%, and 40% w/w of methyl cellulose were fabricated by a casting technique. The inserts were sterilized by gamma radiation at 25 kGy and tested for sterility. The microbiological efficacy of the ocular inserts against Staphylococcus aureus ATCC 6538P and Pseudomonas aeruginosa NCIM 2200 was evaluated by developing an in vitro microbiological model and an in vivo noninvasive rabbit eye model. Parameters of the in vitro microbiological model were varied, and the results correlated with a noninvasive rabbit eye model. The in vitro model proved to be a viable alternative to the rabbit eye model in evaluating the microbiological efficacy of gentamicin sulfate ocular inserts.