A class of soft alkylating compounds as potential anticancer agents was developed. The first examples include alpha-halo esters of various carboxylic acids. A new method for quantitative evaluation of the alkylating reactivity was developed, using a competitive alkylation reactivity was developed, using a competitive alkylation reaction, followed by NMR analysis of the reaction mixture. The method is sensitive and reproducible. One of the two selected soft alkylating agents, chloromethyl hexanoate, was found to have anticancer activity.

A "Soft" corticosteroid, loteprednol etabonate I, designed based on the "inactive metabolite" concept can be used as a safe ophthalmic anti-inflammatory drug. By design, the metabolism of I follows a predicted biotransformation pathway, thus unwanted systemic side effects are avoided. Local side effects are also reduced. Accordingly, in a cross-over study I did not elevate the intraocular pressure (IOP) in rabbits, as opposed to dexamethasone.

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A pattern recognition technique has been used to determine structure-activity relationships for antiinflammatory steroids. Expe.:. rimental results using the human vasoconstrictor test of McKenzie and Stoughton and the rat granuloma cotton pellet method of Meier were correlated with the various substructural descriptors. Steroids were classified into two categories according to potency and a pattern recognition method was applied to determine their relative ranking. The resulting structure-activity relationships obtained and the relative contributions of the various structural variables for both bioassays are discussed. A synergistic effect was predicted to be in operation between certain pairs of substituents.

Brain-targeted delivery systems based on the dihydropyridine in equilibrium pyridinium salt redox interconversion were synthesized for estradiol, estradiol 3-benzoate, and ethynylestradiol. Initial biological evaluation indicated that while all four compounds synthesized exerted central estrogenic activity as measured by serum LH suppression, only the delivery systems based on the 17-substituted estradiol and ethynylestradiol demonstrated prolonged action (greater than 12 days). The 17-(1-methyl-1,4-dihydronicotinic acid ester) of ethynylestradiol behaved in a similar manner to the previously described estradiol analogue in various assays. Tissue distribution studies in rats showed that administration of the ethynylestradiol derivative resulted in high sustained levels of the corresponding pyridinium salt in the central nervous system (CNS) while blood levels of the oxidized metabolite rapidly fell. The sustained brain levels were associated with a prolonged release of ethynylestradiol. By 24 h, posttreatment, no ethynylestradiol was found by HPLC in the blood while levels of over 20 ng/g of tissue were detected in the CNS. This enhanced central delivery gave a dose- and time-dependent LH suppression, which indicated a three- to fivefold increased potency compared with the corresponding estradiol derivative.