[Pros and cons of preservatives in eyedrops. Questionnaire for practitioners and experimental studies with reference to the requirements of the German Pharmacopoeia of August 1978]

Abstract

The first part of this paper deals with the regulations in the DAB 8/78 stating that eye-drops are to be preserved. A questionnaire prepared by the German Association of Ophthalmologists is analyzed. The four questions put to 353 ophthalmologists and answered by 350 of these concern the need for unpreserved eye-drops because of the danger of allergization; the expiry date once the bottle has been opened; infections due to eye-drops without preservatives; and the need for eye-drops made up by pharmacists. The second part deals with studies on the pH-values of lacrimal fluid in cases of normal and decreased lacrimation, as well as with the bactericidal action of the normal tear fluid containing lysozyme and lactotransferrine and various eye-drops containing preservatives. The authors conclude that the general addition of preservatives to eye-drops, especially to those containing antiphlogistic and astringent substances, is unnecessary. Concerning the expiry date on the bottle, it is suggested that the period of use be extended to three months, thus helping to cut costs.