| 主权项 |
1. A compound of formula I, or a physiologically acceptable salt thereof: wherein R1 is selected from:
hydrogen,an optionally substituted C1-6 alkyl group (preferably C1-3 alkyl, e.g. methyl),an optionally substituted C3-7 cycloalkyl group (preferably C3-5 cycloalkyl),an optionally substituted aryl group (preferably one containing from 6-20 carbon atoms, more preferably one containing either 6 or 10 carbon atoms, e.g. phenyl), anda group -L-X in which L and X are as defined herein; R2 to R7 are each independently selected from:
hydrogen,an optionally substituted C1-6 alkyl group (preferably C1-3 alkyl, e.g. methyl),an optionally substituted C2-6 alkenyl group (preferably C2-4 alkenyl),an optionally substituted C3-7 cycloalkyl group (preferably C3-5 cycloalkyl), andan optionally substituted aryl group (preferably one containing from 6-20 carbon atoms, more preferably one containing either 6 or 10 carbon atoms, e.g. phenyl); L is either a direct bond or a linker, preferably a linker cleavable in vivo by one or more biological enzymes (e.g. esterases, amidases and/or oxidative enzymes) or by a hydrolytic reaction; X is a functional group, preferably a hydrophilic group (the term “hydrophilic” means that this portion of the molecule has a tendency to interact with or be dissolved by water or other polar solvents and/or substances), a group capable of polymerization (preferably lactic acid, lactide or a vinylic group, e.g. acrylic acid), or a group capable of coupling to a biological molecule (e.g. a peptide or a protein); or is a biocompatible polymer (e.g. polylysine, dextran, polylactic acid, chitosan or alginate, preferably polylysine); and wherein, when R1 is a group -L-X, each L and X may be the same or different. |
