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Roger Bate - One of the best experts on this subject based on the ideXlab platform.
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anti malarial drug quality in lagos and accra a comparison of various quality assessments
2010Co-Authors: Roger Bate, Kimberly HessAbstract:Background: Two major cities in West Africa, Accra, the capital of Ghana, and Lagos, the largest city of Nigeria, have significant problems with substandard pharmaceuticals. Both have actively combated the problem in recent years, particularly by screening products on the market using the Global Pharma Health Fund e.V. Minilab® protocol. Random sampling of medicines from the two cities at least twice over the past 30 months allows a tentative assessment of whether improvements in drug quality have occurred. Since intelligence provided by investigators indicates that some counterfeit producers may be adapting products to pass Minilab tests, the results are compared with those from a Raman spectrometer and discrepancies are discussed. Methods: Between mid-2007 and early-2010, samples of anti-malarial drugs were bought covertly from pharmacies in Lagos on three different occasions (October 2007, December 2008, February 2010), and from pharmacies in Accra on two different occasions (October 2007, February 2010). All samples were tested using the Minilab® protocol, which includes disintegration and active ingredient assays as well as visual inspection, and most samples were also tested by Raman Spectrometry. Results: In Lagos, the failure rate in the 2010 sampling fell to 29% of the 2007 finding using the Minilab® protocol, 53% using Raman Spectrometry, and 46% using visual inspection. In Accra, the failure rate in the 2010 sampling fell to 54% of the 2007 finding using the Minilab® protocol, 72% using Raman Spectrometry, and 90% using visual inspection. Conclusions: The evidence presented shows that drug quality is probably improving in both cities, especially Lagos, since major reductions of failure rates over time occur with all means of assessment. Many more samples failed when examined by Raman Spectrometry than by Minilab® protocol. The discrepancy is most likely caused by the two techniques measuring different aspects of the medication and hence the discrepancy may be the natural variation in these techniques. But other explanations are possible and are discussed.
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anti malarial drug quality in lagos and accra a comparison of various quality assessments
Malaria Journal, 2010Co-Authors: Roger Bate, Kimberly HessAbstract:Two major cities in West Africa, Accra, the capital of Ghana, and Lagos, the largest city of Nigeria, have significant problems with substandard pharmaceuticals. Both have actively combated the problem in recent years, particularly by screening products on the market using the Global Pharma Health Fund e.V. Minilab® protocol. Random sampling of medicines from the two cities at least twice over the past 30 months allows a tentative assessment of whether improvements in drug quality have occurred. Since intelligence provided by investigators indicates that some counterfeit producers may be adapting products to pass Minilab tests, the results are compared with those from a Raman spectrometer and discrepancies are discussed. Between mid-2007 and early-2010, samples of anti-malarial drugs were bought covertly from pharmacies in Lagos on three different occasions (October 2007, December 2008, February 2010), and from pharmacies in Accra on two different occasions (October 2007, February 2010). All samples were tested using the Minilab® protocol, which includes disintegration and active ingredient assays as well as visual inspection, and most samples were also tested by Raman Spectrometry. In Lagos, the failure rate in the 2010 sampling fell to 29% of the 2007 finding using the Minilab® protocol, 53% using Raman Spectrometry, and 46% using visual inspection. In Accra, the failure rate in the 2010 sampling fell to 54% of the 2007 finding using the Minilab® protocol, 72% using Raman Spectrometry, and 90% using visual inspection. The evidence presented shows that drug quality is probably improving in both cities, especially Lagos, since major reductions of failure rates over time occur with all means of assessment. Many more samples failed when examined by Raman Spectrometry than by Minilab® protocol. The discrepancy is most likely caused by the two techniques measuring different aspects of the medication and hence the discrepancy may be the natural variation in these techniques. But other explanations are possible and are discussed.
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pilot study comparing technologies to test for substandard drugs in field settings
Social Science Research Network, 2009Co-Authors: Roger Bate, Richard Tren, Kimberly Hess, Lorraine Mooney, Karen PorterAbstract:Researchers procured a range of antimalarial, antibiotic and antimycobacterial drugs from cities in six countries: Ghana, India, Kenya, Nigeria, Tanzania, and Uganda. Semi-quantitative thin-layer chromatography (TLC) and disintegration tests, Raman Spectrometry, and near-infrared (NIR) Spectrometry were used to measure the concentration of active ingredients and excipients (Spectrometry only) to determine whether the tested samples were of good quality. Overall, 15% of tested samples failed TLC, 13% of tested samples failed disintegration tests, 41% of tested samples failed NIR Spectrometry, and 47% of tested samples failed Raman Spectrometry. The drug testing technologies were qualitatively compared in terms of time, cost, and reliability for identifying substandard drugs in the field. NIR and Raman Spectrometry compared favorably to TLC in most respects except cost. If the indirect costs of TLC— including requirements for a climate controlled location and trained laboratory staff—are considered, the cost advantage of TLC may disappear in developing countries.
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physical and chemical stability of expired fixed dose combination artemether lumefantrine in uncontrolled tropical conditions
Social Science Research Network, 2009Co-Authors: Roger Bate, Richard Tren, Kimberly Hess, Amir AttaranAbstract:Background: New artemisinin combination therapies pose difficulties of implementation in developing and tropical settings because they have a short shelf-life (two years) relative to the medicines they replace. This limits the reliability and cost of treatment, and the acceptability of this treatment to health care workers. A multi-pronged investigation was made into the chemical and physical stability of fixed dose combination artemether-lumefantrine (FDC-ALU) stored under heterogeneous, uncontrolled African conditions, to probe if a shelf-life extension might be possible.Methods: Seventy samples of expired FDC-ALU were collected from private pharmacies and malaria researchers in seven African countries. The samples were subjected to thin-layer chromatography (TLC), disintegration testing, and near infrared Raman Spectrometry for ascertainment of active ingredients, tablet integrity, and chemical degradation of the tablet formulation including both active ingredients and excipients.Results: Seventy samples of FDC-ALU were tested in July 2008, between one and 58 months post-expiry. 68 of 70 (97%) samples passed TLC, disintegration and Raman Spectrometry testing, including eight samples that were post-expiry by 20 months or longer. A weak linear association (R2 = 0.33) was observed between the age of samples and their state of degradation relative to brand-identical samples on Raman Spectrometry. Sixty-eight samples were retested in February 2009 using Raman Spectrometry, between eight and 65 months post-expiry. 66 of 68 (97%) samples passed Raman Spectrometry retesting. An unexpected observation about African drug logistics was made in three batches of FDC-ALU, which had been sold into the public sector at concessional pricing in accordance with a World Health Organization (WHO) agreement, and which were illegally diverted to the private sector where they were sold for profit.Conclusion: The data indicate that FDC-ALU is chemically and physically stable well beyond its stated shelf-life in uncontrolled, tropical conditions. While these data are not themselves sufficient, it is strongly suggested that a re-evaluation of the two-year shelf-life by drug regulatory authorities is warranted.
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physical and chemical stability of expired fixed dose combination artemether lumefantrine in uncontrolled tropical conditions
Malaria Journal, 2009Co-Authors: Roger Bate, Richard Tren, Kimberly Hess, Amir AttaranAbstract:New artemisinin combination therapies pose difficulties of implementation in developing and tropical settings because they have a short shelf-life (two years) relative to the medicines they replace. This limits the reliability and cost of treatment, and the acceptability of this treatment to health care workers. A multi-pronged investigation was made into the chemical and physical stability of fixed dose combination artemether-lumefantrine (FDC-ALU) stored under heterogeneous, uncontrolled African conditions, to probe if a shelf-life extension might be possible. Seventy samples of expired FDC-ALU were collected from private pharmacies and malaria researchers in seven African countries. The samples were subjected to thin-layer chromatography (TLC), disintegration testing, and near infrared Raman Spectrometry for ascertainment of active ingredients, tablet integrity, and chemical degradation of the tablet formulation including both active ingredients and excipients. Seventy samples of FDC-ALU were tested in July 2008, between one and 58 months post-expiry. 68 of 70 (97%) samples passed TLC, disintegration and Raman Spectrometry testing, including eight samples that were post-expiry by 20 months or longer. A weak linear association (R2 = 0.33) was observed between the age of samples and their state of degradation relative to brand-identical samples on Raman Spectrometry. Sixty-eight samples were retested in February 2009 using Raman Spectrometry, between eight and 65 months post-expiry. 66 of 68 (97%) samples passed Raman Spectrometry retesting. An unexpected observation about African drug logistics was made in three batches of FDC-ALU, which had been sold into the public sector at concessional pricing in accordance with a World Health Organization (WHO) agreement, and which were illegally diverted to the private sector where they were sold for profit. The data indicate that FDC-ALU is chemically and physically stable well beyond its stated shelf-life in uncontrolled, tropical conditions. While these data are not themselves sufficient, it is strongly suggested that a re-evaluation of the two-year shelf-life by drug regulatory authorities is warranted.
Maria Jose Ayoracanada - One of the best experts on this subject based on the ideXlab platform.
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pharmaceutical powders analysis using ft Raman Spectrometry simultaneous determination of sulfathiazole and sulfanilamide
Talanta, 2008Co-Authors: Macarena Lopezsanchez, Maria Jose Ruedasrama, A Ruizmedina, Antonio Molinadiaz, Maria Jose AyoracanadaAbstract:Abstract A procedure for rapid quantitative analysis of pharmaceutical powders is described. Powdered samples were measured in a rotating cell in order to avoid sub-sampling problems by increasing the irradiated area. Quantitative determination of sulfathiazole and sulfanilamide, using a simple univariate calibration model is proposed. Even though both antibacterials are of the same chemical family (sulfonamides), the richness of structural information contained in the Raman spectra allowed their determination using the area of two selected bands (1255 and 1629 cm−1 for sulfathiazole and sulfanilamide, respectively). Relative standard deviation (R.S.D.) values (n = 10) of 3.35% and 3.46% for sulfathiazole and sulfanilamide, respectively, demonstrate the good reproducibility of the measurement technique with the rotating cell. The method was successfully applied to the analysis of synthetic mixtures and commercial pharmaceutical powders. The procedure is suitable to be applied to pharmacopoeial uniformity of content testing of batches.
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determination of oil and water content in olive pomace using near infrared and Raman Spectrometry a comparative study
Analytical and Bioanalytical Chemistry, 2004Co-Authors: Barbara Muik, Antonio Molinadiaz, Bernhard Lendl, Luis Perezvillarejo, Maria Jose AyoracanadaAbstract:Near infrared (NIR) reflectance and Raman Spectrometry were compared for determination of the oil and water content of olive pomace, a by-product in olive oil production. To enable comparison of the spectral techniques the same sample sets were used for calibration (1.74-3.93% oil, 48.3-67.0% water) and for validation (1.77-3.74% oil, 50.0-64.5% water). Several partial least squares (PLS) regression models were optimized by cross-validation with cancellation groups, including different spectral pretreatments for each technique. Best models were achieved with first-derivative spectra for both oil and water content. Prediction results for an independent validation set were similar for both techniques. The values of root mean square error of prediction (RMSEP) were 0.19 and 0.20-0.21 for oil content and 2.0 and 1.8 for water content, using Raman and NIR, respectively. The possibility of improving these results by combining the information of both techniques was also tested. The best models constructed using the appended spectra resulted in slightly better performance for oil content (RMSEP 0.17) but no improvement for water content.
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direct reagent free determination of free fatty acid content in olive oil and olives by fourier transform Raman Spectrometry
Analytica Chimica Acta, 2003Co-Authors: Antonio Molinadiaz, Barbara Muik, Bernhard Lendl, Maria Jose AyoracanadaAbstract:Abstract Fourier transform (FT) Raman Spectrometry in combination with partial least squares (PLS) regression was used for direct, reagent-free determination of free fatty acid (FFA) content in olive oils and olives. Oils were directly investigated in a simple flow cell. Milled olives were measured in a dedicated sample cup, which was rotated eccentrically to the horizontal laser beam during spectrum acquisition in order to compensate sample heterogeneity. Both external and internal (leave-one-out) validation were used to assess the predictive ability of the PLS calibration models for FFA content (in terms of oleic acid) in oil and olives in the range 0.20–6.14 and 0.15–3.79%, respectively. The root mean square error of prediction (RMSEP) was 0.29% for oil and 0.28% for olives. The predicted FFA contents were used to classify oils and olives in different categories according to the European Union regulations. Ninety percent of the oil samples and 80% of the olives were correctly classified. These results demonstrate that the proposed procedures can be used for screening of good quality olives before processing, as well as, for the on-line control of the produced oil.
Barbara Muik - One of the best experts on this subject based on the ideXlab platform.
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determination of oil and water content in olive pomace using near infrared and Raman Spectrometry a comparative study
Analytical and Bioanalytical Chemistry, 2004Co-Authors: Barbara Muik, Antonio Molinadiaz, Bernhard Lendl, Luis Perezvillarejo, Maria Jose AyoracanadaAbstract:Near infrared (NIR) reflectance and Raman Spectrometry were compared for determination of the oil and water content of olive pomace, a by-product in olive oil production. To enable comparison of the spectral techniques the same sample sets were used for calibration (1.74-3.93% oil, 48.3-67.0% water) and for validation (1.77-3.74% oil, 50.0-64.5% water). Several partial least squares (PLS) regression models were optimized by cross-validation with cancellation groups, including different spectral pretreatments for each technique. Best models were achieved with first-derivative spectra for both oil and water content. Prediction results for an independent validation set were similar for both techniques. The values of root mean square error of prediction (RMSEP) were 0.19 and 0.20-0.21 for oil content and 2.0 and 1.8 for water content, using Raman and NIR, respectively. The possibility of improving these results by combining the information of both techniques was also tested. The best models constructed using the appended spectra resulted in slightly better performance for oil content (RMSEP 0.17) but no improvement for water content.
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direct reagent free determination of free fatty acid content in olive oil and olives by fourier transform Raman Spectrometry
Analytica Chimica Acta, 2003Co-Authors: Antonio Molinadiaz, Barbara Muik, Bernhard Lendl, Maria Jose AyoracanadaAbstract:Abstract Fourier transform (FT) Raman Spectrometry in combination with partial least squares (PLS) regression was used for direct, reagent-free determination of free fatty acid (FFA) content in olive oils and olives. Oils were directly investigated in a simple flow cell. Milled olives were measured in a dedicated sample cup, which was rotated eccentrically to the horizontal laser beam during spectrum acquisition in order to compensate sample heterogeneity. Both external and internal (leave-one-out) validation were used to assess the predictive ability of the PLS calibration models for FFA content (in terms of oleic acid) in oil and olives in the range 0.20–6.14 and 0.15–3.79%, respectively. The root mean square error of prediction (RMSEP) was 0.29% for oil and 0.28% for olives. The predicted FFA contents were used to classify oils and olives in different categories according to the European Union regulations. Ninety percent of the oil samples and 80% of the olives were correctly classified. These results demonstrate that the proposed procedures can be used for screening of good quality olives before processing, as well as, for the on-line control of the produced oil.
Dmitri V Voronine - One of the best experts on this subject based on the ideXlab platform.
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facile residue analysis of recent and prehistoric cook stones using handheld Raman Spectrometry
Journal of Raman Spectroscopy, 2015Co-Authors: Laura Short, Alston V Thoms, Bin Cao, Alexander M Sinyukov, Amitabh Joshi, Rob Scully, Virgil Sanders, Dmitri V VoronineAbstract:We performed food residue analysis of fire-cracked rock (FCR) from experimental and prehistoric earth ovens using a handheld Raman Spectrometry. Progress in modern optical technology provides a facile means of rapid non-destructive identification of residue artifacts from archaeological sites. For this study spectral signatures were obtained on sotol (Dasylirion spp.) experimentally baked in an earth oven as well as sotol residue on an experimentally used processing tool. Inulin was a major residue component. The portable handheld Raman spectrometer also detected traces of inulin on experimental boiling stones used to boil commercially obtained inulin. The Raman spectra of inulin and sotol may be useful as signatures of some wild plant residues in archaeology. Spectroscopic analysis of millennia-old FCR from prehistoric archaeological sites in Fort Hood, TX revealed the presence of residues whose further identification requires improvement of current optical methods. Copyright © 2014 John Wiley & Sons, Ltd.
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facile residue analysis of recent and prehistoric cook stones using handheld Raman Spectrometry
arXiv: Optics, 2013Co-Authors: Laura Short, Alston V Thoms, Bin Cao, Alexander M Sinyukov, Amitabh Joshi, Rob Scully, Virgil Sanders, Dmitri V VoronineAbstract:We performed food residue analysis of cook-stones from experimental and prehistoric earth ovens using a handheld Raman Spectrometry. Progress in modern optical technology provides a facile means of rapid non-destructive identification of residue artifacts from archaeological sites. For this study spectral signatures were obtained on sotol (Dasylirion spp.) experimentally baked in an earth oven as well as sotol residue on an experimentally used processing tool. Inulin was the major residue component. The portable handheld Raman spectrometer also detected traces of inulin on boiling stones used to boil commercially obtained inulin. The Raman spectra of inulin and sotol may be useful as signatures of wild plant residues in archaeology. Spectroscopic analysis of millennia-old cook-stones from prehistoric archaeological sites in Fort Hood, TX revealed the presence of residues whose further identification requires improvement of current optical methods.
Amir Attaran - One of the best experts on this subject based on the ideXlab platform.
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physical and chemical stability of expired fixed dose combination artemether lumefantrine in uncontrolled tropical conditions
Social Science Research Network, 2009Co-Authors: Roger Bate, Richard Tren, Kimberly Hess, Amir AttaranAbstract:Background: New artemisinin combination therapies pose difficulties of implementation in developing and tropical settings because they have a short shelf-life (two years) relative to the medicines they replace. This limits the reliability and cost of treatment, and the acceptability of this treatment to health care workers. A multi-pronged investigation was made into the chemical and physical stability of fixed dose combination artemether-lumefantrine (FDC-ALU) stored under heterogeneous, uncontrolled African conditions, to probe if a shelf-life extension might be possible.Methods: Seventy samples of expired FDC-ALU were collected from private pharmacies and malaria researchers in seven African countries. The samples were subjected to thin-layer chromatography (TLC), disintegration testing, and near infrared Raman Spectrometry for ascertainment of active ingredients, tablet integrity, and chemical degradation of the tablet formulation including both active ingredients and excipients.Results: Seventy samples of FDC-ALU were tested in July 2008, between one and 58 months post-expiry. 68 of 70 (97%) samples passed TLC, disintegration and Raman Spectrometry testing, including eight samples that were post-expiry by 20 months or longer. A weak linear association (R2 = 0.33) was observed between the age of samples and their state of degradation relative to brand-identical samples on Raman Spectrometry. Sixty-eight samples were retested in February 2009 using Raman Spectrometry, between eight and 65 months post-expiry. 66 of 68 (97%) samples passed Raman Spectrometry retesting. An unexpected observation about African drug logistics was made in three batches of FDC-ALU, which had been sold into the public sector at concessional pricing in accordance with a World Health Organization (WHO) agreement, and which were illegally diverted to the private sector where they were sold for profit.Conclusion: The data indicate that FDC-ALU is chemically and physically stable well beyond its stated shelf-life in uncontrolled, tropical conditions. While these data are not themselves sufficient, it is strongly suggested that a re-evaluation of the two-year shelf-life by drug regulatory authorities is warranted.
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physical and chemical stability of expired fixed dose combination artemether lumefantrine in uncontrolled tropical conditions
Malaria Journal, 2009Co-Authors: Roger Bate, Richard Tren, Kimberly Hess, Amir AttaranAbstract:New artemisinin combination therapies pose difficulties of implementation in developing and tropical settings because they have a short shelf-life (two years) relative to the medicines they replace. This limits the reliability and cost of treatment, and the acceptability of this treatment to health care workers. A multi-pronged investigation was made into the chemical and physical stability of fixed dose combination artemether-lumefantrine (FDC-ALU) stored under heterogeneous, uncontrolled African conditions, to probe if a shelf-life extension might be possible. Seventy samples of expired FDC-ALU were collected from private pharmacies and malaria researchers in seven African countries. The samples were subjected to thin-layer chromatography (TLC), disintegration testing, and near infrared Raman Spectrometry for ascertainment of active ingredients, tablet integrity, and chemical degradation of the tablet formulation including both active ingredients and excipients. Seventy samples of FDC-ALU were tested in July 2008, between one and 58 months post-expiry. 68 of 70 (97%) samples passed TLC, disintegration and Raman Spectrometry testing, including eight samples that were post-expiry by 20 months or longer. A weak linear association (R2 = 0.33) was observed between the age of samples and their state of degradation relative to brand-identical samples on Raman Spectrometry. Sixty-eight samples were retested in February 2009 using Raman Spectrometry, between eight and 65 months post-expiry. 66 of 68 (97%) samples passed Raman Spectrometry retesting. An unexpected observation about African drug logistics was made in three batches of FDC-ALU, which had been sold into the public sector at concessional pricing in accordance with a World Health Organization (WHO) agreement, and which were illegally diverted to the private sector where they were sold for profit. The data indicate that FDC-ALU is chemically and physically stable well beyond its stated shelf-life in uncontrolled, tropical conditions. While these data are not themselves sufficient, it is strongly suggested that a re-evaluation of the two-year shelf-life by drug regulatory authorities is warranted.
