The novel positively charged pro-drugs of lH-imidazo[4, 5-c]quinolin-4-aminesand related compounds in the general formula (1) 'Structure 1' orformula (2 ) 'Structure 2 ' were designed and synthesized. The compoundsof the general formula (1) 'Structure 1' or formula (2) 'Structure2' indicated above can be prepared from lH-imidazo[4, 5-c]quinolin-4-aminesand related compounds, by reaction with suitable acetic anhydride or aceticchloride. The positively charged amino groups of these pro-drugs not only largelyincreases the solubility of the drugs in water, but also bonds to the negativecharge on the phosphate head group of membranes. This bonding will disturb themembrane a little bit and may make some room for the lipophilic portion of the prodrug.When the molecules of membrane move, the membrane may 'crack' a littlebit due to the bonding of the prodrug. This will let the prodrug insert into themembrane. At pH 7.4, only about 99% of the amino group is protonated. When the aminogroup is not protonated, the bonding between the amino group of the prodrug andthe phosphate head group of the membrane will disassociate, and the prodrug willenter the membrane completely. When the amino group of the prodrug flips to theother side of the membrane and thus becomes protonated, then the prodrug is pulledinto the cytosol, a semi-liquid concentrated aqueous solution or suspension.The results suggest that the pro-drugs diffuse through human skin -25 times fasterthan do lH-imidazo[4, 5-c]quinolin-4-amines and related compounds. In plasma,more than 90% of these pro-drugs can change back to the parent drugs in a few minutes.The prodrugs can be used medicinally in treating any lH-imidazo[4,5-c]quinolin-4-aminesand related compounds-treatable conditions in humans or animals. The prodrugscan be administered transdermally for any kind of medical treatments and avoidmost of the side effects of 1H-im
