Variation in the volume of lubricating eyedrops available in the brazilian market

ABSTRACT

Objective:

To evaluate the intra and inter variations of eye drops volume dispensed from bottles available on the market.

Methods:

Five bottles of lubricant eye drops were studied and nineteen volunteers participated in this study. The average mass from 20µl of eye drops was obtained using accuracy micropipette and balance, and used as standard for comparison with the mass of the drops obtained by the volunteers. Five drops of each vial were individually weighed with the tube perpendicular to the balance, using the first and second fingers of the right hand, so that the pressure was applied only in the middle of the flask. The experiments were performed in a room temperature (21±1°C).

Results:

All eye drops bottles showed a statistically significant variation on masses of the drops obtained by examiners when compared with the standard average weight of 0.0182±0,0014g, except when compared A with D eye drops, with no statistically significant variation.

Conclusion:

This study demonstrates the lack of uniformity of drops dispensed by eye drops bottles available in the market and its inadequacy to the real need, since the dispensed drops are larger than indicated.This fact becomes a problem when it comes to long treatment period, especially with expensive drops as indicated for glaucoma therapy. In this sense, the standardization of drops of eye drops is necessary.

Keywords:
Lubrificant eye drop/administration & dosage; Ophtalmic solutions/administration & dosage; Instillation, drug