Studies on in vivorelease of dexamethasone from carboxymethyl konjac glucomannan pellets in rats

Objective To study in vivo release of dexamethasone(Dex) from carboxymethyl konjac glucomannan(CMKGM) pellets and evaluate colon-specific drug delivery characteristics of the pellets.Methods Compared with Dex containing carboxymethyl cellulose suspension,the concentration of Dex in plasma and dejecta after intragastric administrated to rats were measured periodically by HPLC,and used to calculate the relative targeting drug delivery index(DDI).Results Compared with the suspension,the Tmax of the pellets was about 1h,the Tmax of drug in plasma shifted from 4h to 8h,the Cmax decreased significantly from(6.46±0.92) mg/L to(1.33 ±0.36) mg/L(P0.01),the AUC0→24 decreased significantly from(70.72±9.62) mg·L-1·h-1 to(15.82±4.01) mg·L-1·h-1(P0.01);the amount of drug excreted in dejecting from 0h to 24h after administration increased significantly from(29.20±5.77) μg to(198.2±38.07) μg(P0.01).The DDI value of the pellets to deject was 30.34 against the suspension.Conclusion Dex-containing CMKGM pellets may have the location delivery properties.