Tape products containing ketoprofen have transdermal analgesic and anti-inflammatory effects. We compared the physicochemical properties (water-vapor permeability, peel force, peel force-time curve) between one brand-name product and eight generic products. Regarding the measurement of water-vapor permeability, the formulations using methacrylic acid n-butyl acrylate copolymer (MBA) adhesives showed higher water-vapor permeability than those using styrene isopropyl styrene block copolymer (SIS) adhesives. In the case of the formulation using SIS adhesive, the central part of the formulation had higher water-vapor permeability than both ends. In the 90-degree peel test using the methods of adhesion testing, significant differences were observed between the products, especially as the various application times (5 min, 30 min, 9 h and 24 h) increased. This may be because the longer the time of attachment to the adherend, the more the adhesive force with the adherend increased due to the "anchoring effect" of the adhesive. The measurement of the peel force-time curve showed different curves among the products, especially in the peel force curve of Teikoku after 24 h, which showed two characteristic peak curves. Furthermore, when the peel forces at 25°C and 40°C were compared, Mohrus and Toko showed significantly higher values at 40°C compared to 25°C. This study showed that there are many generic drugs with formulation characteristics different from those of brand-name drugs, and that there is a large difference among the products in terms of adhesion and detachment.
Keywords: Water-vapor permeability; brand-name drug; generic drug; peel adhesion; tape containing ketoprofen.