Comparison of Simvastatin Tablets from the US and International Markets Obtained via the Internet

Abstract

Background: Convenient access to prescription drugs produced outside the US has been facilitated by the Internet. Of greatest concern to clinicians and policy-makers is product quality and patient safety. The Food and Drug Administration has issued warnings to potential buyers that the safety of drugs purchased through the Internet cannot be guaranteed and may present consumers with a health risk from substandard products. Objective: To determine whether generic simvastatin tablets and capsules obtained via the Internet from international markets are equivalent to the US innovator product regarding major aspects of pharmaceutical quality. Methods: Twenty simvastatin tablets and capsules were obtained for pharmaceutical analysis: 19 generic samples from international Internet pharmacy Web sites and the US innovator product. Tablet samples were tested according to US Pbarmacopeial (USP) guidelines where applicable, using high-performance liquid chromatography, disintegration, dissolution, weight variation, hardness, and assessment of physical characteristics. These tests are often used to detect formulation defects of drug products during the manufacturing process. Results: Several international samples analyzed were not comparable to the US product in one or more aspects of quality assurance testing, and significant variability was found among foreign-made tablets themselves. Five samples failed to meet USP standards for dissolution and 2 for content uniformity. Among all samples, variability was observed in hardness, weight, and physical characterization. Conclusions: Results suggest that manufacturing standards for the international generic drug products compared with the US innovator product are not equivalent with regard to quality attributes. These findings have implications for safety and effectiveness that should be considered by clinicians to potentially safeguard patients who choose to purchase foreign-manufactured drugs via the Internet.