Carboxymethylcellulose sodium has been used in the preparation of microcapsules by coacervation. In order to prepare microcapsules of indo-methacin, the drug was dispersed in the aqueous polymer solution and this was added to an aluminium sulfate solution. Drug loss during the preparation of the microcapsules was minimal. The release of the drug followed an apparent zero process and there was a four- to eight-fold reduction in the release rate compared with the uncoated drug. The zero-order rate constant could be related to the coating ratio (Salib etal., 1989).
Was this article helpful?