| Telmisartan is an non–peptin ACH receptor, which is used as an antihepertensive drug in the treatment of all kinds of hepertension. Solid dispersion technology and micronization are employed to increase solubility and dissolution of telmisartan, which is water-insoluble. Bioavailability is improved by changing the existing form including granularity and crystalline form, which is beneficial to reduce dosage of clinical use, toxicity and side effect. Besides, silica gel is used as hydrophilic carrier to improve the stability of the micropowder of telmisartan.Through dissolution test, the final formulation and preparation technology are obtained, which is that: 0.1 g telmisartan is dissolved into NaOH solution, and 0.4 g silica gel is added. After stirring uniformly, dilute hydrochloric acid is used to accommodate PH value to 7.0. The suspension is stirred at a low speed for 3 h, filtered and desiccated in vacuum drying oven for 12 h at 50℃. Then the product is ground, sieved by 80 mesh and preserved in desiccator.Quality inspection is conducted and results are obtained: Telmisartan is mainly absorpted to the surface and pores of silica gel as amorphous state. The micropowder is prone to absorb moisure and should be conserved under dried conditions. Good stability is showed by the stability test. The dissolution test in vivo shows that accumulative release is about 90﹪in 90 mins. And the dissolution profile confirms to Higuchi model closely. |
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