Generic selection criteria for safety and patient benefit [VI]: Comparing the physicochemical and pharmaceutical properties of brand-name, generic, and OTC felbinac tapes

We measured the pH, water-vapor permeability, adhesive force, peeling-force, elongation rate, support flexibility, and peeling time of medicinal and over-the-counter (OTC) tape preparations containing felbinac. When measuring the pH of each preparation, Felnabion (pH 4.5) was weakly acidic, and EMEC and Tokuon (pH 7.0) were neutral. When measuring the water-vapor permeability of each preparation, that of a generic product, EMEC (380 g/m2/24h), was twice as high as that of a brand-name product, Seltouch (189 g/m2/24 h). The adhesive force was measured using the ball tack test. The adhesive forces of OTC drugs, Salomethyl, Homepass, and Tokuhon (1.04 g), were higher than that of Seltouch (0.06 g). Concerning peeling-force measurement, the peeling-forces of a generic product, Falzy (4.15 N), and an OTC drug, Omuneed (4.89 N), were higher than that of Seltouch (0.91 N). The elongation rates of a generic product, Sumilu (319%), and OTC drugs, Nabolin (298%) and Homepass (299%), were higher than that of Seltouch (251%), but that of Tokuhon (72%) was lower. The support flexibilities of EMEC (150 degrees) and Tokuhon (131 degrees) were higher than that of Seltouch (96 degrees). In addition, the peeling time of Seltouch was 120 min or more, whereas those of EMEC and Nabolin were 1.4 and 0.2 min, respectively. These results suggest that the differences in pharmaceutical properties, such as the pH, water-vapor permeability, adhesive force, peeling-force, elongation rate, support flexibility, and peeling time, among the preparations markedly influence patients' subjective comfortableness. The results of this study facilitated individuals’ comfortableness-matched drug selection.