Chiang Mai Journal of Science

The main objective of this study was to produce an artificial tear formulation incorporating chitosan. The variable factors were concentration of chitosan, type of dissolving vehicle, effect of buffer system and sterilization and stability of the preparation. Furthermore, the optimal formulation was also compared with a commercial product. The viscosity of the artificial tear correlated directly with the concentration of chitosan. The acid that was suitable for use as a vehicle was lactic acid. The appropriate buffer system was borate buffer. Sterilization by autoclaving reduced the viscosity of the artificial tear. The optimum formulation consisted of 0.1% w/v chitosan in lactic acid with controlled pH using borate buffer. The pH of this formulation was 5.97. No irritation was detected during testing in rabbit’s eyes. This artificial tear fluid adhered to eyes longer than the commercial product. The physical properties of the formulation did not change under the stability test. The final product was a clear solution which could be stored at room temperature.