Research Advances on in vitro Release of Sustained and Controlled Release Preparations

Objective To introduce the progress in the researches on in-vitro release of sustained and controlled release preparations in order to offer some information for the development of sustained and controlled release preparations of traditional Chinese medicine. Methods Access to domestic and foreign literature,installations,methods and examples for testing in vitro release rate of sustained and controlled release preparations in the United States Pharmacopeia were introduced.The degree of the release affected by ions and ionic strength in release medium and the recent research of sustained-release preparation of the Traditional Chinese medicine of balance-release of the complex ingredients were described.In vitro release test for sustained and controlled release preparations were summarized and induced. Results Reciprocating cylinder and flow through cell can evaluate the quality of sustained and controlled release preparations of chemical medicines,predict its effect in vivo and establish a good in vivo-vitro correlation. Conclusion Reciprocating cylinder and flow through cell are very important devices for measuring the in vitro release of sustained and controlled release preparations,which is useful for the development of sustained release drug delivery system in traditional Chinese medicine.