The invention provides compounds of formula ##STR1## in which formula R.sub.1 and R.sub.2 are identical or different and denote:(1) taken separately: a hydrogen atom, a linear or branched C.sub.1 -C.sub.4 alkyl radical, an unsubstituted phenyl radical or a phenyl radical substituted with a halogen atom, with a C.sub.1 -C.sub.4 alkoxy radical or with a C.sub.1 -C.sub.4 alkoxy radical;(2) taken together either(a) a polymethylene linkage; or(b) a benzene ring; or(c) a cyclic linkage containing a nitrogen atom to constitute an isothiazolopyridinone derivative; m being able to have the values 0 or 1; the group A in the formula (IV) denoting the group ##STR2## where R.sub.8 corresponds to a hydrogen atom, a methyl radical, a hydroxymethyl radical or a --CH.sub.2 O--CO--Ret group. The invention also provides a process for preparing the abovementioned compounds and also drug compositions and cosmetic compositions containing them.