New amoxicillin–poly(lactic acid)‐based conjugates: synthesis and in vitro release of amoxicillin

Long‐term antibiotic treatments are required to cure many diseases. Coupling a bioactive compound to a biocompatible polymer offers, in general, many advantages such as better stabilization of drug and controlled release. The work reported deals with the synthesis of new conjugates based on amoxicillin and oligomers of biocompatible and biodegradable poly(lactic acid), as well as release studies of amoxicillin. These new conjugates were obtained via a Curtius rearrangement or acyl chloride activation, leading to substituted urea or amide bonds between amoxicillin and polymer, respectively. Structures of the conjugates were assessed using Fourier transform infrared and ¹H NMR spectroscopy, double‐detection size exclusion chromatography and electrospray ionization mass spectrometry. In vitro release profiles of amoxicillin in phosphate buffered saline were determined using high‐performance liquid chromatography, and the release rates of amoxicillin from the two conjugates were compared. Copyright © 2010 Society of Chemical Industry