Comparison of Brand-name and Generic Products of Latanoprost Ophthalmic Solution with Respect to the Sense of Use

Abstract

Many generic products of latanoprost ophthalmic solution are commercially available. For pharmacists' guidance, patients often ask questions, such as the total number of drops to be used per bottle. However, materials, including package inserts, that can be obtained from pharmaceutical companies do not provide such information, such as the total number of drops, the volume of a drop, or sense of use regarding each preparation. In this study, we compared the total number of drops, the weight of a drop, squeezing force, and sense of use using brand-name and generic products of latanoprost ophthalmic solution to establish selection criteria.

The weight of a drop exceeded 25 mg in all products, but there were significant differences among the products. In generic products, the total number of drops per bottle was lower than in the brand-name product (112.6 ± 0.9 drops), showing significant differences (10 to 20 drops). The squeezing force required for dripping differed among the products (1.5 to 5-fold). The sense-of-use score regarding the rigidity of an eye drop container reduced with the increase in the squeezing force, showing a negative correlation. The utilization of this information may improve glaucoma patients' adherence and/or reduce costs, providing beneficial information for adopting pharmaceutical preparations in medical institutions.