Advances in the thin layer chromatographic analysis of counterfeit pharmaceutical products: 2008–2019

Sherma, Joseph; Rabel, Fred

doi:10.1080/10826076.2019.1610772

Cited by 14 publications

(11 citation statements)

References 63 publications

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“…Therefore, these robust approaches are not accessible for low-to middle-income countries where the greatest need for analytical detection is needed 18 . Rapid and simple approaches which can also be used in remote locations such as colorimetry and thin-layer chromatography (TLC) [19][20][21] are usually less sensitive but require less expertise. Spectroscopic methods such as near-infrared, mid-4 infrared (MIR), Raman and benchtop nuclear magnetic resonance [22][23][24][25] have shown great potential but provide more insight into the selectivity than the accurate analysis of concentration and thus more likely suitable for falsified medicines than substandard medicines.…”

Section: Introductionmentioning

confidence: 99%

Detection of falsified clopidogrel in the presence of excipients using voltammetry

2021

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Section: Introductionmentioning

confidence: 99%

Detection of falsified clopidogrel in the presence of excipients using voltammetry

2021

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“…However, the quality of tea extracts and tea products on the market can be quite different. This is especially true for powdery products that are susceptible to falsification, counterfeiting or imitation, as it is more difficult to prove authenticity after comminution [ 6 , 7 , 8 , 9 ]. In addition, blending of tea leaves or powders is commonly used for processing to guarantee a constant tea quality and compensate for deviations caused by cultivation and environment [ 10 , 11 ].…”

Section: Introductionmentioning

confidence: 99%

Effect-Directed Profiling of Powdered Tea Extracts for Catechins, Theaflavins, Flavonols and Caffeine

et al. 2021

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The antioxidative activity of Camelia sinensis tea and especially powdered tea extracts on the market, among others used as added value in functional foods, can considerably vary due to not only natural variance, but also adulteration and falsification. Thus, an effect-directed profiling was developed to prove the functional effects or health-promoting claims. It took 3–12 min per sample, depending on the assay incubation time, for 21 separations in parallel. Used as a fast product quality control, it can detect known and unknown bioactive compounds. Twenty tea extracts and a reference mixture of 11-bioactive compounds were investigated in parallel under the same chromatographic conditions by a newly developed reversed phase high-performance thin-layer chromatographic method. In eight planar on-surface assays, effect-directed tea profiles were revealed. Catechins and theaflavins turned out to be not only highly active, but also multi-potent compounds, able to act in a broad range of metabolic pathways. The flavan-3-ols acted as radical scavengers (DPPH∙ assay), antibacterials against Gram-positive Bacillus subtilis bacteria, and inhibitors of tyrosinase, α-glucosidase, β-glucosidase, and acetylcholinesterase. Further effects against Gram-negative Aliivibrio fischeri bacteria and β-glucuronidase were assigned to other components in the powdered tea extracts. According to their specifications, the activity responses of the powdered tea extracts were higher than in mere leaf extracts of green, white and black tea. The multi-imaging and effect-directed profiling was not only able to identify known functional food ingredients, but also to detect unknown bioactive compounds (including bioactive contaminants, residues or adulterations).

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“…This technique uses a simple and reliable apparatus, which does not require large quantities of solvents, is not time-consuming compared to HPLC, and minimizes the effect of the matrix on the analysis. Automation of deposition and quantification and improved quality of stationary phases combined with ready-to-use analytical plates make HPTLC robust, fast, and sensitive which can be coupled with satisfactory sensitivity detectors such as the photodensitometer and mass detector [ 7 – 9 ]. As a result, HPTLC is gradually gaining acceptance in regulatory monographs and in particular for the analysis of natural extracts where matrices are often very complex [ 7 , 10 , 11 ].…”

Section: Introductionmentioning

confidence: 99%

Contribution to the Detection of Poor Quality Sildenafil Drugs in Burkina Faso Using High-Performance Thin-Layer Chromatography

Sakira

Ouattara

Yabré

et al. 2021

Journal of Analytical Methods in Chemistry

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In substandard drugs enforcement, there is a need to develop reliable, fast, and inexpensive analytical methods. Due to its very characteristics, HPTLC offers opportunities for the development of methods that meet these requirements. This technique was used to develop and validate a method for the determination of sildenafil in pharmaceutical formulations from the licit and illicit supply chain in Burkina Faso. Taking into account optimization parameters such as measurement wavelength and mobile phase composition, the best elution quality is found at the maximum signals of spots on silica plates at 305 nm, using a mixture of dichloromethane-methanol mixture 9 : 1 (v/v) proportions. The method developed under these conditions was validated using the accuracy profile as a decision tool. The establishment of the response function curves allowed the choice of the polynomial function applied to the peak areas. This mathematical model provides a validity range between 0.4 and 0.6 mg/mL. The application of the developed and validated method to collected samples allowed the detection of two substandard drugs and confirmed the poor quality of drugs in the illicit market. More data using this approach in a variety of drug molecules could lead to the establishment of databases of counterfeit drugs in Burkina Faso.

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Advances in the thin layer chromatographic analysis of counterfeit pharmaceutical products: 2008–2019

Cited by 14 publications

References 63 publications

Detection of falsified clopidogrel in the presence of excipients using voltammetry

Detection of falsified clopidogrel in the presence of excipients using voltammetry

Effect-Directed Profiling of Powdered Tea Extracts for Catechins, Theaflavins, Flavonols and Caffeine

Contribution to the Detection of Poor Quality Sildenafil Drugs in Burkina Faso Using High-Performance Thin-Layer Chromatography

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