The subject compounds, which are adapted for the site-specific/sustained delivery of centrally acting drug species to the brain, are:(a) compounds of the formula[D--DHC] (I) wherein [D] is a centrally acting drug species, and [DHC] is the reduced, biooxidizable, blood-brain barrier penetrating lipoidal form of a dihydropyridine.revreaction.pyridinium salt redox carrier, with the proviso that when [DHC] is ##STR1## wherein R is lower alkyl or benzyl and [D] is a drug species containing a single NH.sub.2 or OH functional group, the single OH group when present being a primary or secondary OH group, said drug species being linked directly through said NH.sub.2 or OH function group to the carbonyl function of [DHC], then [D] must be other than a sympathetic stimulant, steroid sex hormone or long chain alkanol; and(b) non-toxic pharmaceutically acceptable salts of compounds of formula (I) wherein [D] is a centrally acting drug species and [DHC] is the reduced, biooxidizable, blood-brain barrier penetrating lipoidal form of a dihydropyridine.revreaction.pyridinium salt redox carrier. The corresponding ionic pyridinium salt type drug/carrier entitles [D--QC].sup.+ X.sup.- are also disclosed.