While changing one or more of the desired path and the speed by incorporating a predetermined chemical in a valid parent drug compounds in the metabolism of inert or very weak activity of the parent drug compounds directed to the non-toxic metabolites also expand the intravenous infusion of the modified drug to be formed so as to maintain the efficacy, methods and compositions for treating persistent pulmonary hypertension in human neonates is disclosed. Chemical arrangement, the φ-R-X-R '(φ, has been specially added to the parent drug compound through or a metabolically stable connections are already present in the parent drug compound phenyl , substituted aryl or heteroaryl system; R is 0 to an alkyl or alkene having a branched or unbranched carbon, metabolically to or φ already present in the parent drug compound are those attached to the parent drug compounds through a stable connection; X is carboxyl, which is metabolically specially added to the parent drug compounds through a stable connection to the R, in sulfoxyl or phosphatyl functional group There; and R 'is branched or unbranched alkyl having 1 to 10 carbons, or alkenyl or aralkyl group, or a structural element already present as the original part of the parent drug compound) it is.