Chitosan whisker grafted with oligo(lactic acid) nanoparticles via a green synthesis pathway: Potential as a transdermal drug delivery system.

Chitosan whisker (CSWK) grafted with oligo(lactic acid) (OLA) nanoparticles (NPs) in water is developed to aid transferring therapeutic agents through the skin in a transdermal drug delivery system. Although several works in the past have shown grafting of poly(lactic acid) onto chitosan, the present work shows a green grafting system for the first time. The nano-sized CSWK provided effective conjugation of lactic acid even in a heterogeneous water-based system followed by polycondensation to form OLA. The OLA chain length is controlled by the lactic acid content and modulates the lipophilicity of CSWK-OLA. This fine tunes not only the size of the NPs but also the encapsulation efficiency of the hydrophobic drug lidocaine. A detailed chemical structure analysis, including the factors related to the development of NPs, is presented and extends the studies to the model drug encapsulation and delivery.