Systemic application of cysteine-2:1-crotonal adduct for pharmacokinetic studies of tumor models in rats and mice.

A selective cytostatic effect is demonstrated for systemic application of the Michael adduct of crotonal (CAS 4170-30-3) with cysteine (CAS 52-90-4). As in earlier studies, our initial model was the Ehrlich ascites tumor (EAT) in mouse. Tablets containing 150 mg of the substance were implanted subcutaneously. Substance concentrations were found to be higher in the ascites fluid than in the blood. A better model, the Walker-256 carcinosarcoma (Wa256), was used subsequently. Due to its rapid growth, results are available promptly. The EAT results were confirmed and it was also found that there are higher substance concentrations in the cytoplasma of Wa-256 cells than in cells in neighboring liver tissue. During the period when substance was being liberated from the tablet, substance concentration in the blood was constant, and considerably lower than in ascites fluid or cytoplasma. This confirms that cysteine-2:1-crotonal adduct can be applied systemically from a subcutaneous depot to a model tumor in a cytostatic concentration.