Poor quality antimalarial medicines still represent a threat to the public health, especially in ... more Poor quality antimalarial medicines still represent a threat to the public health, especially in Sub-Saharan Africa who bears a disproportionate share of the global burden of malaria. It is essential and urgent to strengthen mechanisms against counterfeit medicines. One of the approaches is regular market surveillance through quality controls. 12 samples of artemether/lumefantrine were collected from formal and informal drug sellers in Cotonou (Benin) as well as additional other similar samples from Rwanda (13 samples) and from D.R. Congo (9 samples). Thin Layer Chromatography (TLC) as classical and simple identification test was applied in Benin while an analytical chemistry laboratory in Belgium (ULg, Pharmacy Department) was asked for further analyses with HPLC and Raman spectroscopy using a developed and validated HPLC method for rapid analysis of artemether/lumefantrine. The results obtained in Belgium confirmed the lack of the two active ingredients in the suspected sample of ...
Journal of Pharmaceutical and Biomedical Analysis, 2017
As one of the world's most significant public health ... more As one of the world's most significant public health challenges in low- and middle-income countries, HIV/AIDS deserves to be treated with appropriate medicines, however which are not spared from counterfeiting. For that, we developed screening and specific HPLC methods that can analyze 18 antiretroviral medicines (ARV) and 4 major excipients. Design of experiments and design space methodology were initially applied for 15 ARV and the 4 excipients with prediction thanks to Monte Carlo simulations and focusing on rapidity and affordability thus using short column and low cost organic solvent (methanol) in gradient mode with 10mM buffer solutions of ammonium hydrogen carbonate. Two other specific methods dedicated to ARV in liquid and in solid dosage formulations were also predicted and optimized. We checked the ability of one method for the analysis of a fixed-dose combination composed by emtricitabine/tenofovir/efavirenz in tablet formulations. Satisfying validation results were obtained by applying the total error approach taking into account the accuracy profile as decision tool. Then, the validated method was applied to test two samples coded A and B, and claimed to contain the tested ARV. Assay results were satisfying only for sample B.
Chewing sticks are secondary forest products used by people of all ages, genders and professions ... more Chewing sticks are secondary forest products used by people of all ages, genders and professions in Benin but less investigated according to species concerned, their importance according to local communities and their pharmacological properties. For that purpose, an ethnobotanical survey was conducted among 105 local informants of 8 districts in southern and central Benin. The informants were requested to list the species used as chewing sticks and to rank them by priority. To assess pharmacological importance, phytochemical screening was done on four species listed as priority according to local perceptions. The most important plant families of chewing sticks harvested are Euphorbiaceae, Combretaceae, Anacardiaceae, Rubiaceae and Rutaceae. We recorded 35 species of chewing sticks which were grouped into three categories. Six major groups of chemical compounds were tested in four species listed as priority: alkaloids, tannins, flavonoids, saponins, steroids, terpenoids and heteroside cardiotonics. Chemical groups found in selected plants have in general positive actions on dental care, but some such as heterosides cardiotonics found in Pseudospondias microcarpa (in traces) are not recommended because of the risks of cardiotoxicity known for these chemical compounds.
Buruli ulcer (BU) imposes a serious economic burden on affected households and on health systems ... more Buruli ulcer (BU) imposes a serious economic burden on affected households and on health systems that are involved in diagnosing the disease and treating patients. Research is needed to find cost-effective therapies for this costly disease. Plants have always been an important source of new pharmacologically active molecules. Consequently we decided to undertake the study of plants used in traditional treatment of BU in Benin and investigate their antimycobacterial activity as well as their chemical composition. Extracts from forty-four (44) plant species were selected on account of reported traditional uses for the treatment of BU in Benin and were assayed for antimycobacterial activities. Crude hydroethanolic extract from aerial parts of Holarrhena floribunda (G. Don) T. Durand and Schinz was found to have significant antimycobacterial activity against M. ulcerans (MIC = 125 g/mL). We describe here the identification of four steroidal alkaloids from Mycobacterium ulcerans growth-inhibiting fractions of the alkaloidal extract of the aerial parts of Holarrhena floribunda. Holadysamine was purified in sufficient amount to allow the determination of its MCI (=50 g/mL). These results give some support to the use of this plant in traditional medicine.
Journal of pharmaceutical and biomedical analysis, Jan 12, 2015
Poor quality antimalarial drugs are one of the public's major health problems in Africa. The ... more Poor quality antimalarial drugs are one of the public's major health problems in Africa. The depth of this problem may be explained in part by the lack of effective enforcement and the lack of efficient local drug analysis laboratories. To tackle part of this issue, two spectroscopic methods with the ability to detect and to quantify quinine dihydrochloride in children's oral drops formulations were developed and validated. Raman and near infrared (NIR) spectroscopy were selected for the drug analysis due to their low cost, non-destructive and rapid characteristics. Both of the methods developed were successfully validated using the total error approach in the range of 50-150% of the target concentration (20%W/V) within the 10% acceptance limits. Samples collected on the Congolese pharmaceutical market were analyzed by both techniques to detect potentially substandard drugs. After a comparison of the analytical performance of both methods, it has been decided to implement th...
Journal of Physiology and Pharmacology Advances, 2013
ABSTRACT Heteroarylaminoethanol’s derivatives can influence functions of the cardiovascular syste... more ABSTRACT Heteroarylaminoethanol’s derivatives can influence functions of the cardiovascular system. To obtain effective compounds able to favorably to influence those functions, a new series of are synthesized. Two of those compounds, which differ in the substitution on the heterocyclic benzofurane, were chosen for a basic pharmacological analysis. On the right atria of a guinea pig heart connected to an isometric transducer in Tyrode solution, we have evaluated the antagonist potency of the compounds; On Tracheal strip isolated and placed under a resting tension of 2 g in a bath filled with Krebs-Henseleit solution we evaluated the ability to antagonize relaxant effect and on isolated depolarized aorta adult Wister rats mounted in an organ bath filled with Krebs-Henseleit solution at 37°C and aerated with a pneumoxide under a resting tension of 1g we evaluated the inhibitory effect on the potassium-induced contraction at concentration 10-8 to 10-5 mol.l-1. Experiments on isolated beating guinea-pig atria both compounds at concentration: 1.0 × 10-6 mol.l-1 decreased basic heart rate and inhibited positive chronotropic effect of isoprenaline (pA2 = 6.70 ± 0.29 and/or 6.72 ± 0.23, resp.), and slightly influenced isoprenaline-mediated relaxation of tracheal guinea pig muscle and relaxed KCl pre-contracted aortal strips of rats. The obtained results were compared with experiments on cardiovascular effect of hybrid héterorylaminoethnols on intact animals. Both compounds given intraperitoneally at doses 5 and 25 mg/kg to the normotensive rats decreased mean arterial blood pressure in range of 7.7-11.80%. Both evaluated compounds could be regarded as candidates for further pharmacological and pharmacokinetic studies. Keywords: Heteroaryl-amino-ethanols, cardiovascular system, anti-isoprenaline activity, isolated atria, isolated aorta. Corresponding author: ERU of Pharmacology, Faculty of Health Sciences; University of Abomey Calavi (UAC). Received on: 13 Nov 2012 Revised on: 11 Oct 2012 Accepted on: 15 Jul 2013 Online Published on: 30 Aug 2013 Original Article ISSN: 2251-7693
As serious but neglected public health problems, poor quality medicines, i.e. for antimalarial me... more As serious but neglected public health problems, poor quality medicines, i.e. for antimalarial medicines, urged to be fought. One of the approaches is to consider the analytical chemistry and separative techniques. In this study, a generic liquid chromatographic method was firstly developed for the purpose of screening 8 antimalarial active ingredients, namely amodiaquine (AQ), piperaquine (PPQ), sulfalene (SL), pyrimethamine (PM), lumefantrine (LF), artesunate (AS), artemether (AM) and dihydroartemisinine (DHA) by applying DoE/DS optimization strategy. Since the method was not totally satisfying in terms of peak separation, further experiments were undergone applying the same development strategy while splitting the 8 ingredients into five groups. Excellent prediction was observed prior to correlation between retention times of predicted and observed separation conditions. Then, a successful geometric transfer was realized to reduce the analysis time focusing on the simultaneous quantification of two WHO's recommended ACTs in anti-malarial fixed-dose combination (AM-LF and AS-AQ) in tablets. The optimal separation was achieved using an isocratic elution of methanol-ammonium formate buffer (pH 2.8; 10 mM) (82.5:17.5, v/v) * These authors have equally contributed to this article. # Corresponding author. J. K. Mbinze et al.
Chewing sticks are secondary forest products used by people of all ages, genders and professions ... more Chewing sticks are secondary forest products used by people of all ages, genders and professions in Benin but less investigated according to species concerned, their importance according to local communities and their pharmacological properties. For that purpose, an ethnobotanical survey was conducted among 105 local informants of 8 districts in southern and central Benin. The informants were requested to list the species used as chewing sticks and to rank them by priority. To assess pharmacological importance, phytochemical screening was done on four species listed as priority according to local perceptions. The most important plant families of chewing sticks harvested are Euphorbiaceae, Combretaceae, Anacardiaceae, Rubiaceae and Rutaceae. We recorded 35 species of chewing sticks which were grouped into three categories. Six major groups of chemical compounds were tested in four species listed as priority: alkaloids, tannins, flavonoids, saponins, steroids, terpenoids and heteroside cardiotonics. Chemical groups found in selected plants have in general positive actions on dental care, but some such as heterosides cardiotonics found in Pseudospondias microcarpa (in traces) are not recommended because of the risks of cardiotoxicity known for these chemical compounds.
Poor quality antimalarial medicines still represent a threat to the public health, especially in ... more Poor quality antimalarial medicines still represent a threat to the public health, especially in Sub-Saharan Africa who bears a disproportionate share of the global burden of malaria. It is essential and urgent to strengthen mechanisms against counterfeit medicines. One of the approaches is regular market surveillance through quality controls. 12 samples of artemether/lumefantrine were collected from formal and informal drug sellers in Cotonou (Benin) as well as additional other similar samples from Rwanda (13 samples) and from D.R. Congo (9 samples). Thin Layer Chromatography (TLC) as classical and simple identification test was applied in Benin while an analytical chemistry laboratory in Belgium (ULg, Pharmacy Department) was asked for further analyses with HPLC and Raman spectroscopy using a developed and validated HPLC method for rapid analysis of artemether/lumefantrine. The results obtained in Belgium confirmed the lack of the two active ingredients in the suspected sample of ...
Journal of Pharmaceutical and Biomedical Analysis, 2017
As one of the world's most significant public health ... more As one of the world's most significant public health challenges in low- and middle-income countries, HIV/AIDS deserves to be treated with appropriate medicines, however which are not spared from counterfeiting. For that, we developed screening and specific HPLC methods that can analyze 18 antiretroviral medicines (ARV) and 4 major excipients. Design of experiments and design space methodology were initially applied for 15 ARV and the 4 excipients with prediction thanks to Monte Carlo simulations and focusing on rapidity and affordability thus using short column and low cost organic solvent (methanol) in gradient mode with 10mM buffer solutions of ammonium hydrogen carbonate. Two other specific methods dedicated to ARV in liquid and in solid dosage formulations were also predicted and optimized. We checked the ability of one method for the analysis of a fixed-dose combination composed by emtricitabine/tenofovir/efavirenz in tablet formulations. Satisfying validation results were obtained by applying the total error approach taking into account the accuracy profile as decision tool. Then, the validated method was applied to test two samples coded A and B, and claimed to contain the tested ARV. Assay results were satisfying only for sample B.
Chewing sticks are secondary forest products used by people of all ages, genders and professions ... more Chewing sticks are secondary forest products used by people of all ages, genders and professions in Benin but less investigated according to species concerned, their importance according to local communities and their pharmacological properties. For that purpose, an ethnobotanical survey was conducted among 105 local informants of 8 districts in southern and central Benin. The informants were requested to list the species used as chewing sticks and to rank them by priority. To assess pharmacological importance, phytochemical screening was done on four species listed as priority according to local perceptions. The most important plant families of chewing sticks harvested are Euphorbiaceae, Combretaceae, Anacardiaceae, Rubiaceae and Rutaceae. We recorded 35 species of chewing sticks which were grouped into three categories. Six major groups of chemical compounds were tested in four species listed as priority: alkaloids, tannins, flavonoids, saponins, steroids, terpenoids and heteroside cardiotonics. Chemical groups found in selected plants have in general positive actions on dental care, but some such as heterosides cardiotonics found in Pseudospondias microcarpa (in traces) are not recommended because of the risks of cardiotoxicity known for these chemical compounds.
Buruli ulcer (BU) imposes a serious economic burden on affected households and on health systems ... more Buruli ulcer (BU) imposes a serious economic burden on affected households and on health systems that are involved in diagnosing the disease and treating patients. Research is needed to find cost-effective therapies for this costly disease. Plants have always been an important source of new pharmacologically active molecules. Consequently we decided to undertake the study of plants used in traditional treatment of BU in Benin and investigate their antimycobacterial activity as well as their chemical composition. Extracts from forty-four (44) plant species were selected on account of reported traditional uses for the treatment of BU in Benin and were assayed for antimycobacterial activities. Crude hydroethanolic extract from aerial parts of Holarrhena floribunda (G. Don) T. Durand and Schinz was found to have significant antimycobacterial activity against M. ulcerans (MIC = 125 g/mL). We describe here the identification of four steroidal alkaloids from Mycobacterium ulcerans growth-inhibiting fractions of the alkaloidal extract of the aerial parts of Holarrhena floribunda. Holadysamine was purified in sufficient amount to allow the determination of its MCI (=50 g/mL). These results give some support to the use of this plant in traditional medicine.
Journal of pharmaceutical and biomedical analysis, Jan 12, 2015
Poor quality antimalarial drugs are one of the public's major health problems in Africa. The ... more Poor quality antimalarial drugs are one of the public's major health problems in Africa. The depth of this problem may be explained in part by the lack of effective enforcement and the lack of efficient local drug analysis laboratories. To tackle part of this issue, two spectroscopic methods with the ability to detect and to quantify quinine dihydrochloride in children's oral drops formulations were developed and validated. Raman and near infrared (NIR) spectroscopy were selected for the drug analysis due to their low cost, non-destructive and rapid characteristics. Both of the methods developed were successfully validated using the total error approach in the range of 50-150% of the target concentration (20%W/V) within the 10% acceptance limits. Samples collected on the Congolese pharmaceutical market were analyzed by both techniques to detect potentially substandard drugs. After a comparison of the analytical performance of both methods, it has been decided to implement th...
Journal of Physiology and Pharmacology Advances, 2013
ABSTRACT Heteroarylaminoethanol’s derivatives can influence functions of the cardiovascular syste... more ABSTRACT Heteroarylaminoethanol’s derivatives can influence functions of the cardiovascular system. To obtain effective compounds able to favorably to influence those functions, a new series of are synthesized. Two of those compounds, which differ in the substitution on the heterocyclic benzofurane, were chosen for a basic pharmacological analysis. On the right atria of a guinea pig heart connected to an isometric transducer in Tyrode solution, we have evaluated the antagonist potency of the compounds; On Tracheal strip isolated and placed under a resting tension of 2 g in a bath filled with Krebs-Henseleit solution we evaluated the ability to antagonize relaxant effect and on isolated depolarized aorta adult Wister rats mounted in an organ bath filled with Krebs-Henseleit solution at 37°C and aerated with a pneumoxide under a resting tension of 1g we evaluated the inhibitory effect on the potassium-induced contraction at concentration 10-8 to 10-5 mol.l-1. Experiments on isolated beating guinea-pig atria both compounds at concentration: 1.0 × 10-6 mol.l-1 decreased basic heart rate and inhibited positive chronotropic effect of isoprenaline (pA2 = 6.70 ± 0.29 and/or 6.72 ± 0.23, resp.), and slightly influenced isoprenaline-mediated relaxation of tracheal guinea pig muscle and relaxed KCl pre-contracted aortal strips of rats. The obtained results were compared with experiments on cardiovascular effect of hybrid héterorylaminoethnols on intact animals. Both compounds given intraperitoneally at doses 5 and 25 mg/kg to the normotensive rats decreased mean arterial blood pressure in range of 7.7-11.80%. Both evaluated compounds could be regarded as candidates for further pharmacological and pharmacokinetic studies. Keywords: Heteroaryl-amino-ethanols, cardiovascular system, anti-isoprenaline activity, isolated atria, isolated aorta. Corresponding author: ERU of Pharmacology, Faculty of Health Sciences; University of Abomey Calavi (UAC). Received on: 13 Nov 2012 Revised on: 11 Oct 2012 Accepted on: 15 Jul 2013 Online Published on: 30 Aug 2013 Original Article ISSN: 2251-7693
As serious but neglected public health problems, poor quality medicines, i.e. for antimalarial me... more As serious but neglected public health problems, poor quality medicines, i.e. for antimalarial medicines, urged to be fought. One of the approaches is to consider the analytical chemistry and separative techniques. In this study, a generic liquid chromatographic method was firstly developed for the purpose of screening 8 antimalarial active ingredients, namely amodiaquine (AQ), piperaquine (PPQ), sulfalene (SL), pyrimethamine (PM), lumefantrine (LF), artesunate (AS), artemether (AM) and dihydroartemisinine (DHA) by applying DoE/DS optimization strategy. Since the method was not totally satisfying in terms of peak separation, further experiments were undergone applying the same development strategy while splitting the 8 ingredients into five groups. Excellent prediction was observed prior to correlation between retention times of predicted and observed separation conditions. Then, a successful geometric transfer was realized to reduce the analysis time focusing on the simultaneous quantification of two WHO's recommended ACTs in anti-malarial fixed-dose combination (AM-LF and AS-AQ) in tablets. The optimal separation was achieved using an isocratic elution of methanol-ammonium formate buffer (pH 2.8; 10 mM) (82.5:17.5, v/v) * These authors have equally contributed to this article. # Corresponding author. J. K. Mbinze et al.
Chewing sticks are secondary forest products used by people of all ages, genders and professions ... more Chewing sticks are secondary forest products used by people of all ages, genders and professions in Benin but less investigated according to species concerned, their importance according to local communities and their pharmacological properties. For that purpose, an ethnobotanical survey was conducted among 105 local informants of 8 districts in southern and central Benin. The informants were requested to list the species used as chewing sticks and to rank them by priority. To assess pharmacological importance, phytochemical screening was done on four species listed as priority according to local perceptions. The most important plant families of chewing sticks harvested are Euphorbiaceae, Combretaceae, Anacardiaceae, Rubiaceae and Rutaceae. We recorded 35 species of chewing sticks which were grouped into three categories. Six major groups of chemical compounds were tested in four species listed as priority: alkaloids, tannins, flavonoids, saponins, steroids, terpenoids and heteroside cardiotonics. Chemical groups found in selected plants have in general positive actions on dental care, but some such as heterosides cardiotonics found in Pseudospondias microcarpa (in traces) are not recommended because of the risks of cardiotoxicity known for these chemical compounds.
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