The Influence Of Solutoi HS-15 On The In Vitro Dissolution & In Vivo Absorption Of Nimodipine After Oral Administration

Nimodipine is a drug clinically used to treat hypertension and other cerebrovascular disease in the dosage forms as injection and oral solid dosages forms. Because of the poor water solubility, the bioavailability for the solid dosage forms as tablet, is only 10% to 30%.To increase the water solubility of this poorly water soluble drug, various methods were used. In this paper, the mixture of Nimodipine with a surface active agent Solutol HS-15 was made with the method of solvent evaporation. The solubility of nimodipine and the mixture of Nimodipine with Solutol HS-15 in various ratio were tested and the result shown that the greater the ratio of Nimodipine to Solutol HS-15, the higher the solubility of nimodipine in water. As to the solubility increase, Solutol HS-15 is better than PEG4000 that is usually used in the preparation of solid dispersion. For the mixture of Nimodipine with Solutol HS-15 in the ratio of 1:1 and 1:4, the solubility of nimodipine in water was increased by 7.4 times that of the pure nimodipine material drug. When compared with the solubility increase of PEG4000, the results shown that Solutol HS-15 was better that PEG4000. The latter when used in the ratio of 4:1 in the solid dispersion, the solubility on nimodipine was increased only times that of pure drug.The in vitro drug release was tested in various media of 37? at the rating speed of 100 rpm. The drug dissolution from the tablet made by the formulation containing Solutol HS-15 was fund to have the fastest drug release, which was higher than that of the tablet without Solutol HS-15 and the marketed domestic nimodipine tablet.The in vivo absorption and bioavailability was tested with rabbits as experimental animals. As the result shown, the bioavailability in the form of AUC0-24 h was 6.2 times higher than that of the capsule made of the pure nimodipine material drug and 1 times higher than the marketed domestic nimodipine.The results obtained in this paper could a reference for the further of the oral solid dosage form of nimodipine and the research of the other poorly water soluble drugs.