Compatibility of verapamil hydrochloride injection in commonly used large-volume parenterals

The visual and chemical compatibilities of verapamil hydrochloride injection in 10 commonly used large-volume solutions packaged in glass, polyolefin, or polyvinyl chloride containers were studied. The mixtures, each containing 40 mg/liter of verapamil hydrochloride, were stored away from light for up to 48 hours at 25 degrees C. The solutions were examined visually for haze, precipitate formation, color change, and evolution of gas immediately after mixing and at 0.25, 1, 3, 8, 24, and 48 hours. Spectrophotometry and thin-layer chromatography were used to test for drug decomposition or chemical incompatibilities. All test methods used showed that no significant degradation of verapamil hydrochloride had taken place in the solutions or through contact with the containers. Slightly higher spectrophotometric readings for dextrose-containing solutions, though within experimental error, could have indicated the presence of dextrose degradation products. Evidence from this study suggests that verapamil hydrocholoride is compatible with the large-volume parenterals studied.