In this communication, we report the synthesis of chitosan (CS, a biodegradable and biocom- patible natural polymer) [1] nanoparticles as drug carriers by ionic gelation. The method is based on ionic interactions between positively charged groups NH3 + of CS (in dilute CH3COOH solution) and negatively charged of sodium tripolyphos- phate, TPP). This mechanism was confirmed by IR analyses: the presence of the P=O and P-O groups at the frequency of 1180 cm-1 and 1250 cm-1 res- pectively for CS-TPP nanoparticles; and the shifts from 1650 cm-1 and 1595 cm-1 , corresponding to C-O and N-H stretching respec-tively in pure CS, to 1636 cm-1 and 1539 cm-1 for CS-TPP nano- particles, indicated the interaction between CS and TPP [2].
