Sibutramine was marketed under the brand name Reductil and prescribed as a treatment for obesity until links to an increased risk of strokes and heart attacks saw it banned by the European Medicines Agency (EMA) in January 2010.
Even before that EMA action it was banned in the European Union food supply including food supplements. It has laso been used in products promoting aid to those sufering erectile dysfunction.
The method has the potential to help customs officials with on-hand testing that could yield major cost savings and better border product policing.
Despite its withdrawal from the market it remains in products on black markets – especially on the internet, although its presence is rarely flagged on-product.
“By putting sibutramine into the products, they are sure to have an effect on weight and people will buy more,” Eric Deconinck of the Scientific Institute of Public Health in Belgium explained to NutraIngredients.
The sibutramine masquerade
He said the products were being sold as 100% natural, containing a mixture of plant extracts, vitamins and minerals, so consumers were completely unaware that they were taking an unlisted synthetic drug.
“People buying the supplements don’t know they contain sibutramine – they think they are buying a herbal mix. The risks associated with these adulterations cannot be underestimated,” he said.
That said internet chat boards indicate a section of consumers know which products contain the compound – listed or not – and seek them out for that very reason.
The problem facing customs, when they intercept these types of products, is that all weight loss supplements could potentially be laced with sibutramine
“All these products can be considered as potentially containing adulterants...The differentiation is very difficult for inspectors and customs personnel,” said Deconinck.
Consequently, all products that present a potential risk have to be confiscated and sent to laboratories for analysis – a broad-brush approach that unfairly impacts legitimate food supplement manufacturers.
ATR-IR spectroscopy to the rescue
The researchers said attenuated total reflectance-infrared (ATR-IR) spectroscopy as a fast, easy-to-use method that could be used to perform an initial screening of samples.
“ATR is a sampling technique that is often used in combination with IR, which enables samples to be examined directly in their solid or liquid state without any further sample preparation steps. ATR-IR is therefore very interesting, since it is simple, no sample preparation is necessary and the instruments are rather compact,” wrote the researchers in the Journal of Pharmaceutical and Biomedical Analysis.
125 dietary supplements, which were previously analysed in the laboratory for the presence of adulterants, were subjected to an ATR-IR screening. All the samples were donated by the Federal Agency for Medicines and Health Care Products (FAMHP) in Belgium.
They came from postal packs ordered via internet sites and contained a variety of forms: Capsules, gel capsules, powders, powdered fruit beverages and instant coffee. 5 mg per dosage unit was the most frequently occurring concentration of sibutramine.
No false negatives
ATR-IR detected all adulterated food supplements. There were some false positive results, which meant a small amount of legal supplements would still be confiscated. More importantly, though, there were no false negatives, which meant no adulterated supplements passed the test.
Explaining the reason for the false positive results, Deconinck said: “The problem is that you have a lot of different matrices, for example, the majority of the capsules contain herbal matrices and the powders for drinks contain a mixture of sweeteners and herbal components. That can influence the results.”
Still, the researchers said the approach could be considered “powerful” since it is able to detect dosages of sibutramine ranging from 3 to 20 mg in total amounts of powders ranging from 300 mg (capsules) to 20 g (powder for drinks).
The next step, said Deconinck, was for customs authorities to decide whether they were interested in working with the Scientific Institute of Public Health to further develop the method.
Journal of Pharmaceutical and Biomedical Analysis
15 August 2014 (doi: 10.1016/j.jpba.2014.08.009)
‘Detection of sibutramine in adulterated dietary supplements using attenuated total reflectance-infrared spectroscopy’