Abstract:

Objective To determine the contents of Poloxamer in contact lens care solution by spectrophotometric method, and investigate the effect of the other lubrication composition on the measurement. Methods Five brands of contact lens care solution with hydroxypropyl methyl cellulose (HPMC) were obtained. The interference of HPMC in contact lens care solution was removed by heating and rapid filtering, and the contents of Poloxamer was determined by KI-I2 spectrophotometry. Results For the pre-treated contact lens care solution, the tested wavelength was 500 nm and the development time was 120 min. Favourable linearity was observed when Poloxamer ranged between 0.001 mg/mL and 0.020 mg/mL, with standard curve of Y＝0.050 91X+0.017 15 and r²=0.998 2. Precision (n=6) test revealed that RSD was 1.331 4%, and RSD of daytime repeatability experiment was 2.971 3%. The recovery rates of 80%, 100% and 120% samples ranged between 90% to 105%. Conclusion KI-I₂ spectrophotometry is a convenient, stable and reliable method, and may serve as a mass control method for nonionic surfactant Poloxamer content in contact lens care solution.

Key words: nonionic surfactant, spectrophotometry, contact lens care solution