Optimalization of biocompatible artificial tears containing povidone-iodine according to pharmaceutical technological and microbiological aspects

Microbiological preservatives play a great role in the preparation of artificial tears because they protect the eyes from further microorganisms and the preparation from contamination. In this contribution we are summarizing our experimental results given by pharmaceutical and microbiological optimalization of artificial tears. The incidental adaptability of povidone-iodine (PVP-I) as a preservative in artificial tears was examined compared to usually used materials. Some artificial tears (Oculogutta carbomerae and Oculogutta viscosa) were prepared according to the Formulae Normales Edition VII., others were isotonisated and buffered containing 3.0% and 3.5% povidonum as active substance. The analysed samples as a preservative instead of generally used agents contained 0.10%, 0.05% and 0.01% PVP-I. Reference preparations were dispensed using microbiological preservatives (Cetrimidum, Thiomersalum solutum 0.1%, Benzalconium chloratum solutum 10%). Pharmaceutical (pH, viscosity, freezing-point depression, refraction, surface-tension) and microbiological (breeding on aerobe and anaerobe bacteriological culture medium) trials were made to determine the qualitative property and adaptability of analysed preparations in which we also studied the stability and the microbiological changes after opening them. According to our experimental results we can establish that the PVP-I is suitable as microbiological preservative in the examined preparations.