To develop a kind of gastrointestinal timed-release preparation for Metoprolol Tartrate, nanostructured silica particles were chose for the purpose. Briefly, MCM-41 type mesoporous silica nanospheres with a size of 100-200 nm were synthesized through the reaction of tetraethyl orthosilicate (TEOS) in the water medium at 353 K, with introducing some cetyltrimethyl ammonium bromide (CTAB) as porogens. Various analytical methods, including FT-IR, XRD, TEM, N2 physisorption and thermal analysis, were applied to characterize the final products. Metoprolol Tartrate was then loaded into the mesoporous silica nanospheres by soaking. Results of the release of the drug in simulated gastric juice indicated that the drug can release up to 24 h and its maximum released amount was 4.5%. In the simulated intestinal juice the maximum cumulative released amount of metorprolol was 10.8%.In vitro release behavior revealed that the mesoporous silica were appropriate used as drug delivery system.
