Assessment of the performance of a handheld Raman device for potential use as a screening tool in evaluating medicines quality

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Abstract

The TruScan® handheld Raman device is used for testing finished pharmaceutical products in the field to detect counterfeit and substandard medicines. Present work reports on the device's ability to discriminate between a specific product and similar products from different manufacturers, unrelated medicines, and medicines with different strengths. This investigation evaluated its ability to differentiate between similar drug products of similar or different strengths, focusing on the specificity and precision of the testing. First, several units of the same medicine's dosage form were compared; then comparisons were made between unrelated products, similar products, and products with different strengths. The six pharmaceutical products used in testing were from commonly used analgesic, antimalarial, and antidiarrheal medicines. The results showed that the performance of the TruScan® device depends on the nature and the strength of the dosage form tested; while the device could be suitable for authentication of some finished pharmaceutical products and, hence, could be used to detect some counterfeit medicines, it could not be used to detect substandard medicines. Careful consideration should be given when using the device as a screening tool for counterfeit medicines.

Introduction

The spread of counterfeit medicines is becoming a serious threat to public health worldwide [1]. According to the World Health Organization, spurious/falsely-labeled/falsified/counterfeit medicines are medicines that are deliberately and fraudulently mislabeled with respect to identity and/or source. The prevalence of counterfeit medicines has been blamed for treatment failure [2] and increasing morbidity and mortality, as well as for contributing to the increase of drug resistance. The availability of substandard medicines, which has often been overlooked, represents an equally serious problem, particularly in developing countries.

Controlling the quality of medicines available in the market can be challenging in countries with limited resources. In order to contain these problems and to protect the public from exposure to counterfeit and poor quality medicines, governments must put in place a functional quality control and quality assurance (QC/QA) system. This calls for a reliable method of detecting such products and a strong regulatory framework able to take corrective action when these medicines are found. In many developing countries, the national quality control laboratory and medicines regulatory authority suffer from inadequate resources and a lack of effective enforcement. In addition to financial resources, an effective QC/QA system requires a functional medicines quality control laboratory staffed with qualified analysts.

The pervasive spread of counterfeit and substandard medicines has led to the need for rapid detection of such products throughout the supply chain. Several tools have been used or have been explored for use in screening the quality of medicines in developing countries [1]. The aim of screening is to reduce the number of samples that a national medicines quality control laboratory must test, which subsequently reduces the burden on the laboratory and its limited resources. Based on Thin Layer Chromatography (TLC) test methods, the Minilab® developed by the Global Pharma Health Fund (GPHF) has been on the market for several years. Use of this kit requires training and use of chemicals. TLC can be used to unequivocally identify the active pharmaceutical ingredient (API) in a finished pharmaceutical product and, thus, be used to detect counterfeit medicines. It is, however, a semi-quantitative method. Results obtained with the Minilab® must be confirmed using more robust testing, such as pharmacopeial methods. Despite its limitations, the Minilab® has been used successfully in many settings to detect counterfeit and substandard medicines [3].

Non-invasive spectroscopic methods for authentication of pharmaceutical products and detection of counterfeit medicines have recently elicited increasing interest [4]. Recent reports explored the use of near-infrared (NIR) and Raman spectroscopy in the detection of counterfeit medicines. In one, NIR was used to detect counterfeit antimalarial tablets [5] and, in another, NIR was compared to Raman spectroscopy in the detection of Lipitor® counterfeits [6]. Raman spectroscopy has been used to detect counterfeit Viagra® [7], and a portable Raman instrument has been assessed for screening counterfeit artesunate [8]. Handheld NIR and Raman devices became available recently that are simple to use and quick to produce results. Their ease of operation and high speed of analysis show promise for their potential use as tools in the routine screening of the quality of medicines.

This article reports on the evaluation of the TruScan® handheld Raman device in testing finished pharmaceutical products. The goal of this assessment was to examine the ability of the device to differentiate between similar pharmaceutical drug products with similar and/or different strengths as an indicator of effective use of the device in the field to detect counterfeit and substandard medicines.

Section snippets

Chemicals

Antimalarial medicines were selected in this study because of their common use and the prevalence of counterfeit and substandard products circulating in markets. These specific antimalarials, artesunate and combination sulfadoxine-pyrimethamine (SP) tablets, were included in the study because of previously reported limitations in the testing of these products using a portable Raman device. Ibuprofen and acetyl salicylic acid tablets were chosen because they both offered a range of products with

Precision test

In order to investigate the ability of the device to generate reproducible results, we conducted a match/fail analysis using one unit of a sample to generate a Raman signature, or a reference spectrum, and compare it to several units of the same sample. Six finished pharmaceutical products were used in this test including three antimalarial medicines and zinc sulfate with two different strengths. All the tests were carried out in similar environmental conditions of light and temperature. As

Conclusions

This investigation evaluates the performance of the TruScan® portable Raman device in discriminating between finished pharmaceutical products based on the similarity of the products and their strengths.

The results of our investigation suggest that the device could be used to detect some counterfeit medicines. The instrument is very likely to detect counterfeit medicines that lack API or have the wrong API; however, some factors should be taken into consideration before using the device in

Role of the funding source

This report is made possible by the generous support of the United States Agency for International Development (USAID), under Cooperative Agreement No. GHS-A-00-09-00003-00. The contents are the responsibility of the Promoting the Quality of Medicines Program, implemented by The U.S. Pharmacopeial Convention, and do not necessarily reflect the views of USAID or the United States Government.

Conflict of interest statement

The authors hereby declare that they have no conflict of interest.

Acknowledgements

The authors wish to thank Ms. Marilyn Foster for reviewing and editing the paper, our colleagues at the Promoting the Quality of Medicines program for their input and suggestions, and the United States Agency for International Development and the President's Malaria Initiative for funding this work.

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1

Present address: United States Food and Drug Administration, Center for Drug Evaluation and Research, Office of Manufacturing and Product Quality, 10903 New Hampshire Avenue, Silver Spring, MD 20993, United States.

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