Pharmaceutical evaluation of atorvastatin calcium tablets available on the Internet: A preliminary investigation of substandard medicines in Japan

Substandard medicine is a type of substandard/spurious/falsely labeled/falsified/counterfeit (SSFFC) drug as defined by the WHO that has permeated the distribution of drugs on the Internet, and is accessible without prescription. An influx of substandard medicines is thus a serious matter in many developed countries. Here, Lipitor and its generic drugs containing atorvastatin calcium (ATC), used for the treatment of hyperlipidemia worldwide, were selected as a model prescription drug. Six brands of ATC tablets were purchased from four Japanese-language web sites. Raman spectroscopy and powder X-ray diffraction (PXRD) were employed to determine ATC and ingredients in the tablets. Although PXRD measurements showed no diffraction peaks of ATC because of its low content, a handheld Raman spectrometer detected ATC in unmodified tablets (without crushing). The tablets were assayed for drug content and dissolution profile according to the Japanese Pharmacopoeia, and one product showed an obviously slower drug release. X-ray computed tomography (CT) showed the interior of the tablet in detail and suggested that massive agglomerations caused slow disintegration of the tablet. This is the first report applying X-ray CT to tablets obtained on the Internet and indicates that unqualified prescription drugs are easily distributed on the Internet without any quality assurance.

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