Quality and Authenticity of Metformin Tablets Circulating on Japanese Websites

Abstract

Background Low-quality medicines and falsified medicines represent long-standing problems in developing countries. In Southeast Asia, the circulation of low-quality diabetes drugs (metformin) has been confirmed. It is possible that low-quality metformin has entered Japan via personal import through the Internet. This study evaluated the pharmaceutical quality and authenticity of metformin tablets obtained via the Internet in Japan. Methods In total, 33 samples of 500-mg metformin tablets and 7 samples of extended-release/sustained-release tablets (500, 750, and 1,000 mg) were purchased via personal import in January 2017. Confirmation of a prescription was never requested purchase. The obtained samples were subjected to visual observations and authenticity investigations. Additionally, quantitative analysis, content uniformity and dissolution tests were performed using HPLC–PDA. Results Our authenticity investigations revealed that seven samples were genuine products, whereas the authenticity of the remaining 33 samples was unclear. Referring to United States Pharmacopeia 2014 for validation, four samples failed quality testing, five samples failed content uniformity testing, and two samples failed dissolution testing. Conclusions Our findings illustrate that metformin tablets of poor-quantity and unregistered/unlicensed doses are available online and that it is important to increase consumer awareness about the presence of these medicines on the Internet to prevent the purchase of substandard medicines.

A critical review on the availability of substandard and falsified medicines online: Incidence, challenges and perspectives

“…Visual inspections detected three tablets with abnormalities, including blue and yellow stains and a crack. 23 Carton and packaging insert dosage discrepancy was noted in one sample, which stated 500 mg and 850 mg, respectively. Analysis established the content was 500 mg. 23 Inconsistency was present in packaging languages against the leaflet and declaring manufacturing/distribution countries.…”

“… 23 Carton and packaging insert dosage discrepancy was noted in one sample, which stated 500 mg and 850 mg, respectively. Analysis established the content was 500 mg. 23 Inconsistency was present in packaging languages against the leaflet and declaring manufacturing/distribution countries. 23 Authenticity was based on questionnaire responses from each manufacturer/distributor, covering sample information (e.g.…”

“…Four samples failed content testing, where three samples were 500 mg tablets and one sustained-release tablet. 23 Five samples failed content uniformity testing with values ranging from 16.6 to 54.9. 23 A 500-mg sustained-release tablet and a 1000-mg extended-release tablet failed dissolution testing.…”

“…Analysis established the content was 500 mg. 23 Inconsistency was present in packaging languages against the leaflet and declaring manufacturing/distribution countries. 23 Authenticity was based on questionnaire responses from each manufacturer/distributor, covering sample information (e.g. API content, doses).…”

“…Seven products were deemed to be genuine; however, the authenticity was unclear for the remainder as no response was received. 23 Based on the US Pharmacopoeia (USP), samples were tested for metformin content, content uniformity and dissolution testing. Four samples failed content testing, where three samples were 500 mg tablets and one sustained-release tablet.…”