The present invention provides novel carbamate-based cationic lipids of the general structure: ##STR1## or a salt, or solvate, or enantiomers thereof, wherein (a) R.sub.1 is a lipophilic moiety; (b) R.sub.2 is a positively charged moiety; (c) n is an integer from 1 to 8; (d) X is an anion or polyanion; and (e) m is an integer from 0 to a number equivalent to the positive charge(s) present on the lipid. The present invention further provides compositions of these lipids with polyanionic macromolecules, methods for interfering with protein expression in a cell utilizing these compositions, and a kit for preparing the same.