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Abstract #18324 Published in IGR 3-3
Drop volume of glaucoma medications
Vaidergorn PG; Susanna R Jr; Borges A; Povoa C; Giampani JRevista Brasileira de Oftalmologia 2001; 60: 547-553
PURPOSE: To evaluate drop volume of commonly prescribed glaucoma medications. LOCATION: Servio de glaucoma, clinica oftalmologica, Hospital das Clinicas da FMUSP. METHODS: The authors drop-counted the bottle contents of eight commercially available IOP- lowering medicines: brimonidine 0.2% (Alphagan, Allergan Labs), brinzolamide 1.0% (Azopt, Alcon Labs), betaxolol 0.25% (Betoptic-S, Alcon Labs), timolol 0.5% + dorzolamide 2.0% (Cosopt, Merck Labs), unoprostone (Rescula, CibaVision), timolol 0.5% (Timoptol 0.5, Merck), dorzolamide 2.0% (Trusopt, Merck), and latanoprost 0.005% (Xalatan, Pharmacia). Six bottles were used for each product, and mean drop volume was calculated for each medication individually, as well as for the eight-drug group as a whole. Differences between the eight drugs' drop volumes were examined. RESULTS: The eight medicines' mean drop volume was 35.80 ± 10.38 ml. However, significant differences were found between them: Xalatan™ showed the smallest volume, with a mean of 23.81 ml per drop, while Betoptic-S™, with a mean drop volume of 56.50 ml, the largest. The other medications did not differ statistically from the mean average. CONCLUSIONS: The eight- drug-group mean drop size was found to be larger than necessary, pointing to an expressive amount of drug wastage. Significant differences in drop volume were noted across the medications studied. According to their drop sizes and assuming no wastage, a bottle of Betoptic-S would last 22.2 days (both eyes treated, twice daily), while Xalatan would last for 52.5 days (both eyes treated, once daily). LA: Portuguese
Dr P.G. Vaidergorn, Instituto Central, Av. Dr. Eneas de Carvalho Aguir, 255, Sao Paulo-SP-CEP 05403-000, Brazil. pgelmann@yahoo.com.br
Classification:
11.16 Vehicles, delivery systems, pharmacokinetics, formulation (Part of: 11 Medical treatment)
