Development of Novel Delivery System for Cardiovascular Drug Molsidomine: Influence of Synthesis Method and Conditions on Molsidomine Release From Its Composites With Hydrophilic Silica In Vitro.

Composites of cardiovascular drug molsidomine with silica materials (unmodified and mercaptopropyl modified) were prepared by 2 methods, adsorption and sol-gel technology. The effects of sol pH and release medium pH (1.6 and 7.4) as well as molsidomine loading on the drug release kinetics were also investigated. Mechanisms of molsidomine release from all the synthesized composites were elucidated. The obtained results showed that different principles of the composites formation (adsorption or sol-gel) lead to their different release behavior because the composites obtained by the indicated methods differ by distribution of the drug over the silica matrixes and their capability to degradation. The drug release from the composites prepared by adsorption is characterized by a high burst effect, sustained release up to 36 h irrespective of release medium pH. The release behavior of sol-gel composites depends on the amount of the loaded drug and release medium pH. These effects were explained by different stability of the sol-gel composites with high and low loading in acidic and neutral media. In general case, the ascertained effects are independent on chemistry of the silica surface organic groups.