[Adsorption and desorption of aclarubicin into and from activated carbon particles as drug carrier--an in vitro study].

A new dosage form (ACR-CH), aclarubicin(ACR) adsorbed on activated carbon particles (CH), was studied for adsorption and desorption onto and from CH. The adsorption isotherm at 37 degrees C in saline and phosphate buffer (pH 7.4-7.5) were shown as M = 175 Co.15 and M = 207 Co.24, respectively (M = ACR amount adsorbed on CH, microgram/mg; C = ACR concentration in a free state, microgram/ml). In both fluids, CH adsorbed more than 100-1,000 times more amount of ACR than ACR in a free state. ACR-CH was lavaged 7 times and the released ACR in a free state was measured. The results showed that ACR-CH desorbed constantly a small amount of ACR, namely, 1.5-8 percent of initial concentration of ACR in a free state in saline, 0.1-10% in phosphate buffer, and 0.5-4.0% in Ringer's solution. Under the same conditions, desorption of ACR-CH was measured in dog's blood plasma. The first lavage made ACR-CH desorb at 25.7 +/- 0.85 percent of ACR initial concentration in a free state, and two times' to 7 times' lavage made 1-3%. Overall, 43.3 +/- 0.99% of ACR were desorbed from the activated carbon. It was concluded that ACR-CH slowly released a constant amount of ACR for a long period.