Dispensing Eye Drops from Flexible Plastic Dropper Bottles
Part I: Influence of the packaging characteristics
Luc Van Santvliet and Annick Ludwig
University of Antwerp (U.I.A.), Department of Pharmaceutical Sciences, Laboratory of Pharmaceutical Technology and Biopharmacy, Antwerp (Belgium)
The aim of the present study was to investigate the influence of the dropper tip design and the flexibility of the dropper bottle on the dispensing of eye drops. The force exerted on and the air pressure created inside the dropper bottle were registered when delivering drops separately under standard conditions using a drop dispensing apparatus. The values obtained were compared with those from the drop delivery by healthy volunteers. The smaller the inner aperture diameter of the dropper tip, the more force necessary to dispense a drop, the higher the air pressure difference and the longer the dispensing time. Squeezing the dropper bottle more slowly resulted in a decrease in the parameters measured depending on the inner aperture diameter of the tip. Twice as much force needed to be exerted on a rigid bottle as on a flexible one. The weight of the drops dispensed was directly proportional to the outer orifice diameter of the tip and was influenced by the speed of compressing the bottle. The drop dispensing apparatus simulated the delivery of eye drop by healthy volunteers since the drop weight and dispensing time results correlated well. The volunteers, however, squeezed the dropper bottle more strongly, resulting in larger air pressure differences.
Key words Drop dispensing Â· Eye drops Â· Packaging
Â© ECV- Editio Cantor Verlag (Germany) 1999
pharmind 1999, Nr. 1, Seite 92