Abstract
Ground mixture of N, N-dimethylcarbamoylmethyl α, 2-dimethyl-5H-[1] benzopyrano-[2, 3-b] pyridine-7-acetate (1) with various pharmaceutical ingredients were prepared in order to investigate their dissolution behaviors and bioavailability. Taking into account the weakly basic property of 1, the dissolution rate was determined in the 2nd fluid (pH 6.8) of disintegration test, JP XI. Dissolution rates of the ground mixtures (1 : 1, w/w) of 1 with hydroxypropylcellulose-L (HPC-L), low substituted hydroxypropylcellulose (L-HPC) or lactose respectively, showed a significant increase compared with compound 1 alone. Three kinds of experimental fine granules were prepared ; type A : produced from ground mixture of 1, HPC-L, L-HPC and lactose ; type B : produced from physical mixture having the same composition as type A ; type C : produced 1, L-HPC and lactose. In these fine granules, only type A exhibited pH-independent dissolution profiles. Bioavailability study was carried out in beagle dogs whose gastric acidity was controlled in advance to low levels by administration of omeprazole. The test was conducted in a cross over design. Reflecting their dissolution characteristics, type A granules showed better bioavailability than the others. These results suggest that grinding is useful for the improvement of the dissolution property and bioavailability of 1, a weakly basic compound.
