Abstract
Aclacinomycin is an antitumor anthracycline antibiotic isolated from the culture broth of Streptomyces galilaeus MA144-M1.In this study, the effects of heat, light and pH on the aqueous solution of aclacinomycin hydrochloride (ACM-HC1) were investigated.The following, results were found:
(1) The kinetic studies revealed that the thermal inactivation of ACM-HC1 solution (pH 4.5) was based on the apparent first-order reaction and that ARRHENIUS equation was confirmed to be established between the rate constants and temperatures.When ACM-HC1 solution was stored at 20, 10 and 5°C, the estimated term of ACM-HC1 solution at the time when the initial activity (100%) reduced to 90% residual concentration was 1.5, 6 and 12 months, respectively.
(2) It was clarified by pH-log k profile that ACM-HC1 solution was most stable near at pH 4.5.
(3) The higher the buffer concentration was used, the faster the degradation rate, but there was no difference between the residual activity ratios at the various concentrations of ACM-HC1 solution.
(4) The inactivation of ACM-HC1 solution under sunlight occurred in a type of zero-order reaction so that the faster inactivation rates were obtained at the more diluted concentrations of ACMHCI.
(5) The major degradation products of ACM-HC1 solution were 1-deoxypyrromycin (DP), MA144 Si (Si) and bisanhydroaklavinone (F1).DP and S1 were mainly found at pH below4.0and Fl at pH above5.0.The degradation under sunlight gave Ll (N-monodemethyl ACM) accompanied by the degradation of aglycone moiety in part.
