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. (C) 2017 Elsevier Inc. All rights reserved.