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Abstract #22642 Published in IGR 11-1
Dosage variability of topical ocular hypotensive products: a densitometric assessment
Gaynes BI; Singa RM; Cao YJournal of Glaucoma 2009; 18: 149-152
PURPOSE: To ascertain consequence of variability in drop volume obtained from multiuse topical ocular hypotensive products in terms of uniformity of product dosage. METHODS: Densitometric assessment of drop volume dispensed from 2 alternative bottle positions. RESULTS: All except one product demonstrated a statistically significant difference in drop volume when administered at either a 45° or 90° bottle angle (Student t test, P<0.001). Product-specific drop volume ranged from a nadir of 22.36 μL to a high of 53.54 μL depending on bottle angle of administration. Deviation in drop dose was directly proportional to variability in drop volume. Variability in per drop dosage was conspicuous among products with a coefficient of variation from 1.49% to 15.91%. In accordance with drop volume, all products demonstrated a statistically significant difference in drop dose at 45° versus 90° administration angles. Drop volume was found unrelated to drop uniformity (Spearman r=0.01987 and P=0.9463). CONCLUSIONS: Variability and lack of uniformity in drop dosage is clearly evident among select ocular hypotensive products and is related to angle of drop administration. Erratic dosage of topical ocular hypotensive therapy may contribute in part to therapeutic failure and/or toxicity.
Dr. B.I. Gaynes, Department of Ophthalmology, Rush College of Medicine, Chicago, IL 60612, USA. bgaynes@rush.edu
Classification:
11.16 Vehicles, delivery systems, pharmacokinetics, formulation (Part of: 11 Medical treatment)
