2018 Volume 44 Issue 10 Pages 510-515
A ghost tablet (GT) was observed in a patient immediately after the switching of potassium chloride sustained release tablets from a brand-name formulation (Slow-K® tablets 600 mg) to a generic one (K-SUPPLY® tablet 600 mg). GT is a phenomenon in which the shell of a tablet is excreted in the feces without disintegration after releasing its active ingredient in the gastrointestinal tract. The objective of this study was to access factors leading to this phenomenon when using the generic formulation. A dissolution test based on the Japanese Pharmacopoeia (JP) 17th edition was performed using the paddle method under three sets of experimental conditions (ultra-pure water, ultra-pure water (pH 6.8), JP dissolution test 1st fluid (pH 1.2)). The concentration of potassium eluted in the medium was determined using an ion electrode method. The dissolution of the potassium was almost the same between the brand-name and generic formulations. The brand-name formulation disintegrated within 6 hr under all three sets of experimental conditions. On the other hand, despite the fact that the release of potassium from the generic formulation was comparable to that of brand-name formulation, it showed little disintegration; that is, the shell of tablet remained intact even after 6 hr. It is considered that differences in the change in appearance between the brand-name and generic formulations during the dissolution test led to the GT when using the generic formulation, and the pharmaceutical additives in the generic formulation were responsible for the GT.
