Preparation of steroid esters of hydroxypropyl cellulose

Cellulose Carbonates: A Platform for Promising Biopolymer Derivatives With Multifunctional Capabilities

“…In a first step, the hydroxyl groups of the polysaccharide (A) are allowed to react with phosgene, followed by conversion with the amine (C) or alcohol (D) with the chloroformate moiety (B) obtained. For example, phosgene activation has been used for the preparation of the carbonic acid ester of hydroxypropyl cellulose with testosterone or estrone . However, the activation (A reacts to B) leads to side reactions resulting in the formation of inter‐ and intramolecular carbonates (F) as well as cyclic structures (E).…”

Synthesis and Spectroscopic Characterisation of O-Chlorocarbonyl Derivatives of Bile Acid Methyl Esters

“…7,8,10,11,14 Occasionally, other solvents and amines, like dioxane, 9 dioxane-triethylamine, 15 and diethyl ether-quinoline, 3 have been used.…”

“…In reactions of steroid alcohols with phosgene or its more convenient equivalent, triphosgene, diethyl ether or methylene chloride have been usually used as solvents with or without added pyridine as acid acceptor. 7,8,10,11,14 Occasionally, other solvents and amines, like dioxane, 9 dioxane-triethylamine, 15 and diethyl ether-quinoline, 3 have been used.…”

Prodrugs for the improvement of drug absorption via different routes of administration

“…As a recent example, one may mention dextran, soluble starch or hydroxyethyl starch -based ester -prodrugs of naproxen (31), but other polysaccharides have been tested for their usefulness as transport groups for therapeutic agents. Among them one can mention starch for acetyl salicylic acid (32,33), inulin for procainamide (34,35), agarose for mitomycin (36) or for adriamycin (37), soluble starch for nicotinic acid (38), or for salicylate (39), cellulose for metribuzin (40) or for insulin (41) and hydroxypropyl cellulose for estrone and testosterone (42,43). However, clinical experience with such prodrugs is still too limited for an adequate judgment on this aspect of macromolecular prodrugs.…”