Nylon microcapsules. II: Effect of selected variables on theophylline release

The effect of selected variables on the release characteristics of theophylline microcapsules prepared with 1,6-hexamethylene diamine and sebacoyl chloride via interfacial polycondensation has been investigated. The nature of the microcapsules and the release characteristics of theophylline from the microcapsules were affected by the type of organic phase, particle size, stirring speed, and rate of addition of sebacoyl chloride during the preparation of microcapsules. The aggregation of the final product was generally less at the lower speeds of stirring. Decreasing the rate of addition of sebacoyl chloride increased the aggregation of the final product as well as the release of theophylline. Decreasing the particle size of the microcapsules increased the release of theophylline from the microcapsules.