Detecting Substandard Drugs in Africa

In developing countries, access to medicine is often limited. To make matters worse, widespread counterfeiting often means that even when patients get access to drugs, the drugs are of poor quality. Dr. Mélisande Bernard, of the Agence Générale des Equipements et Produits de Santé, the technical and pharmaceutical service of the public hospital system of Paris, France (Assistance Publique–Hôpitaux de Paris), is helping to address this problem by developing chromatographic methods to detect substandard cardiovascular drugs in Africa. She recently spoke to us about this work.

Photo Credit: Baris Simsek/Getty Images

Q. What are the objectives of the Agence Générale des Equipements et Produits de Santé (AGEPS) AP-HP? What is the focus of your research?A: AGEPS is a public civil pharmaceutical establishment with a hospital framework. It has the general interest mission of providing essential medicines, like orphan or paediatric drugs, and answering the needs of hospital colleagues not currently covered by the traditional pharmaceutical industry. R&D, production, quality control, and regulatory affairs operations are its main activities, but more fundamental scientific research is performed through fruitful interactions with universities.

The Laboratory Department is frequently solicited for its analytical knowledge and skill in raw materials and finished product control. In this context, pharmaceutical teams from hospitals often request our help to develop and conduct drug or environmental control studies. Having developed expertise and methods in accordance with international standards (Good Manufacturing Practices [GMP], International Conference on Harmonization [ICH]), and with a good technical platform capability, our laboratory is able to respond to the very specialized needs and demands of the hospital pharmaceutical sector.

Our research is mainly focused on the development and validation of new analytical methods (such as dosage and impurities research) for the control of raw materials and finished products, and the establishment of new monographs usable for routine control and stability studies. We also have expertise in the solid-state study and polymorphism of materials; in content/container interactions; and leachable and extractable analysis.

Chromatography - liquid chromatography (LC), gas chromatography (GC), thin layer chromatography (TLC), and ion chromatography - is an important part of our daily activities, in routine dosage, identity, research impurities, or residual solvents, and for more specialized techniques such as interaction studies, forced degradations, or drug counterfeiting research.

Q. You recently developed a high performance liquid chromatography with tandem mass spectrometry (HPLC–MS–MS) method for the simultaneous detection of substandard cardiovascular drugs in Africa.¹ How did you and your team become involved with this project? What are the long-term objectives?A: We have been involved with an evaluation programme regarding some of the most commonly prescribed cardiovascular drugs in Africa, to test a number of tablets - including acenocoumarol, amlodipine, atenolol, captopril, furosemide, hydrochlorothiazide, and simvastatin - obtained from different locations in a variety of African countries. At the beginning of the project, colleagues from the Saint‑Antoine Hospital and INSERM 970 Unit, Paris, France, searched for a laboratory capable of developing analytical methods for a large number of dosages in a short timeframe, and of providing critical expertise on results and improvement propositions. Because the Laboratory Department is GMP certified, we were able to answer those specifications.

Q. Where were samples collected from and why were these locations chosen?A: Cardiovascular diseases are among the most serious health problems in Africa and therefore cardiovascular drugs represent a large sector of the pharmaceutical market, making that class of drugs a target for counterfeiters.
The aim of the present study was to assess the overall quality of medicines used in cardiology and available on the legal (pharmacy and hospital) and illegal (street markets, etc.) marketplaces in the capitals or near the border cities of eight African countries (Benin, Burkina Faso, Congo, Guinea, Ivory Coast, Mauritania, Nigeria, and Senegal). Locations near to border cities are known to be traditional platforms of fraudulent drug trafficking.

Q. What were your findings? What were the advantages of your approach compared to existing methods?
A: For better performance and organization, a simultaneous approach was undertaken, developed, and validated according to international standards (ICH). The HPLC method was optimized for the separation of the seven cardiovascular drugs and degradation products formed in solution. Analysis was performed by liquid chromatography coupled to electrospray ionization tandem mass spectrometry (LC–ESI–MS–MS). Chromatographic (including column type and composition of mobile phase) and mass detection conditions were optimized through several trials to obtain good resolution and symmetric peak shape. Because the molecular structures and polarity of the seven compounds are very different, reversed-phase columns were the optimal choice to properly separate the selected compounds.
We also had to allow for the fact that fragmentation pathways upon chemical ionization of acenocoumarol, captopril, and furosemide have not been described in detail so far. Therefore, tandem experiments were performed to identify the most specific transitions suitable for the identification and quantitation of these three analytes.

Q. This was a pilot study, so how did you optimize and ensure that the method was suitable for routine use?
A: The method must be specific, sensitive, precise, and accurate enough to identify and quantify the seven substances in drug products in a single run. We used the gradient LC separation performance in conjunction with MS multiple reaction monitoring (MRM) detection, using two specific mass transitions, to strengthen the identification approach. The choice of column and the gradient HPLC programme were optimized for the separation of the seven cardiovascular drugs. The method performance was also studied in the presence of degradation products formed in solution. We then optimized the run time and volume solutions to increase efficiency and cost savings.

Linearity, limits of quantification, precision, repeatability, trueness, and robustness were validated as per ICH guidelines. This method has been successfully applied to the routine analysis of cardiovascular drugs randomly sampled in Africa in search of counterfeit medicines.

Q. In your opinion, what do analysts need to consider when developing chromatographic methods for determining drug quality?A: Dual information (retention times and MRM ratios) allows a much more reliable identity control of the active substance, which was particularly required in the present study. The “ease of use” part of the method development was also a real challenge, but was essential, since we had in mind that this method could be implemented all around the world, with more or less means, in search of counterfeits.

Q. Where do you see your research taking you in the future?
A: We are now working on dissolution techniques for this study. We are expanding our knowledge in HPLC method development to other drugs and their degradation products.²

Dr Mélisande Bernard is a Hospital Practitioner - Pharmacist at Agence Générale des Equipements et Produits de Santé (AGEPS) AP‑HP in Paris, France. Her skills include drug and medical device evaluation, pharmaceutical engineering, quality assurance, analytical chemistry, and biocompatibility studies.

References

1. M. Bernard, W. Akrout, C. Tran Van Buu, C. Metz, M. Antignac, N. Yagoubi, and B. Do, Journal of Separation Science DOI 10.1002/jssc.201401301 (2014).
2. H. Sadou Yaye, P.H. Secretan, T. Henriet, M. Bernard, F. Amrani, W. Akrout, P. Tilleul, N. Yagoubi, and B. Do, J. Pharm. Biol. Anal. 105(74–83) DOI:10.1016/j.jpba.2014.11.046 (2015).

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