Poly (L-lysine citramide), a water-soluble bioresorbable carrier for drug delivery: Aqueous solution properties of hydrophobized derivatives

Poly(L-lysine citramide) (PLCA), a novel biocompatible and bioresorbable water-soluble polymer, was designed as a macromolecular prodrug carrier coupling drugs to hydrophilic carriers generally leads to hydrophobization of the precursor macromolecules which then form micelle-like water-dispersed aggregates or are completely insoluble. To study these phenomena, hydrophobization of PLCA was investigated. Alkyl groups (C7 and C12) were covalently attached to the lysine of the polymer which was prepared by either step-growth polymerization or selective hydrolysis of alkylated derivatives. Hydrophobized macromolecules formed nanosized multimolecular aggregates in aqueous media. The size of these aggregates was influenced by concentration, ionic strength, degree of ionization, alkyl substitution and alkyl group length.