An oestradiol-linked nitrosourea and site-directed chemotherapy in mammary carcinoma.

The half-life, peak concentration, peak accumulation and tissue availability of the DNA-crosslinking nitrosourea 1-(2-chloroethyl)-1-nitrosocarbamoyl-L-alanine (CNC-alanine) and its oestradiol-linked derivate (CNC-alanine-oestradiol-17-ester) were studied in liver, lung, spleen, uterus and mammary carcinomas in female Sprague-Dawley rats with chemically induced mammary carcinomas. Compared with CNC-alanine, the ester had a longer half-life, higher peak concentration, increased peak accumulation and enhanced tissue availability in all tissues. In oestradiol receptor positive mammary carcinomas, the oestradiol-linked drug showed a 2 times higher peak concentration, a 5 times longer half-life, a 10 times increased peak accumulation and a 20 times greater tissue availability compared with CNC-alanine. Oestradiol-linked nitrosoureas may offer new perspectives for site-directed chemotherapy of oestradiol receptor positive breast cancer.