Browsing by Author "Chikowe, I."
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Item Further Validation of a Rapid Screening Semiquantitative Thin-Layer Chromatographic Method for Marketed Antimalarial Medicines for Adoption in Malawi(Journal of Analytical Methods in Chemistry, 2018-05) Osei-Safo, D.; Chikowe, I.; Harrison, J.J.E.K.; Yeboah, D.K.; Addae-Mensah, I.A recently developed semiquantitative thin-layer chromatographic (SQ-TLC) assay has been employed in postmarketing surveillance of antimalarial medicines used in Malawi prior to HPLC assay. Both methods gave analogous results in a significant majority of the samples, with a good correlation ( r = 0.9012) for the active pharmaceutical ingredients of the dosage forms assayed. Artemether-containing medicines had the highest percentage (92.67%) of samples with comparable results for both assays. The lowest percentage (66.67%) was observed in artesunate-containing medicines. The SQ-TLC method was validated for specificity, accuracy, precision, linearity, and stability according to the International Conference on Harmonisation guidelines, with the results falling within acceptable limits. For specificity, retention factor values of the test samples and reference standards were comparable, while accuracy and precision of 91.1 ± 5.7% were obtained for all samples. The method was linear in the range 1.0–2.0 µ g/spot with a correlation coefficient of r = 0.9783. Stability tests also fell within acceptable limits. In this study, we present the validation of the SQ-TLC method and propose its adoption as a rapid screening tool for field estimation of the quality of antimalarial and other essential medicines in Malawi and other parts of the developing world prior to a more accurate HPLC assay.Item Post Marketing Surveillance Of Active Pharmaceutical Ingredients (Api) In Antimalarial Drugs Used In Malawi(University of Ghana, 2013-07) Chikowe, I.; Addae-Mensah, I.; Osei-Safo, D.; University of Ghana, College of Basic and Applied Sciences, School of Physical and Mathematical Sciences, Department of ChemistryThe use of poor quality antimalarials causes low bioavailability of the active pharmaceutical ingredients (APIs) to the drug targets resulting in treatment ineffectiveness or failure and parasite resistance over a short period of drug usage. Resistance has rendered the hitherto cheap and effective drugs like chloroquine and sulphadoxine/pyrimethamine ineffective, resulting in their replacement with the more expensive artemisinin-based combination therapy (ACT) for malaria treatment. The high cost of the ACTs has made them attractive to counterfeiters leading to the proliferation of poor quality antimalarials on the drug markets. One hundred and twelve (112) samples of antimalarial drugs were purchased from licensed and unlicensed markets in all parts of Malawi. Samples were subjected to visual inspection of dosage form and packaging, registration verification with the Pharmacy, Medicines and Poisons Board of Malawi, basic tests and semi-quantitative thin layer chromatography (SQ-TLC) and HPLC tests to quantify the APIs in the samples and compare with pharmacopoeial specifications and the manufacturers’ claims. The results showed an 85 % registration status with all samples purported to be imported and 100% compliance with visual inspection requirements and basic tests confirming the presence of requisite APIs. The results of the SQ-TLC showed that 4.88% of artemether/lumefantrine (Atm/Lum) FDC samples were compliant with pharmacopoeial specifications, 2.44% were borderline compliant and a further 92.68% were non-compliant (48.15% of Atm component was overdose and 51.85% under dose; 57.14% of Lum component was overdose and the remaining 42.86% under dose). The HPLC results confirmed this result with 4.88% found to be compliant and 95.12% non-compliant (48.15% overdose and 51.85% under dose for Atm component; 50% overdose and 50% under dose for Lum component). SQ-TLC tests on artesunate/sulphadoxine/pyrimethamine (Ats/SP) samples showed that 77.78% were non-compliant all of which were under dose, while 22.22% were borderline compliant. However, the HPLC results showed a compliant percentage of 11.10% and 88.90% non-compliance (under dose). The dihydroartemisinin/piperaquine phosphate (Dha/Pp) samples recorded SQ-TLC percentage of 42.86% being compliant, 14.29% borderline compliant and 42.86% non-compliant with all the non-compliant quantities of the components found under dose. With HPLC, they were found to be 28.57% compliant, 7.14% borderline compliant and 64.29% non-compliant (under dosed components). Dihydroartemisinin/sulphadoxine/pyrimethamine (Dha/SP) samples were found to be 100% non-compliant for both SQ-TLC and HPLC tests. The quantities of the APIs in the non-compliant Dha/S/P samples fell within the range of 51% and 84%. Samples containing sulphadoxine/pyrimethamine (SP) were found to be 4.35% compliant, 8.70% borderline compliant and 86.95% non-compliant using SQ-TLC method (25.00% of the noncompliant pyrimethamine component overdose, 75.00% under dose and 100.00% of sulphadoxine under dose). With HPLC, half (50.00%) of the samples that were borderline compliant were found to be non-compliant with the remaining half being compliant giving rise to the following results: 8.70% and 91.30% compliant and non-compliant respectively with all noncompliant sulphadoxine and 72.73% of pyrimethamine being under dose and 27.27% of the quantities of pyrimethamine being overdose. None of the quinine samples were compliant with SQ-TLC (28.57% borderline compliant, 71.43% non-compliant and overdose). HPLC analysis found 30.77%, 15.38% and 53.85% to be compliant, borderline compliant and non-compliant (85.71% overdosed) respectively. Generally, 85.71% failure rate was found arising from Atm/Lum (95.12%), Dha/P (64.30%), Dha/SP (100.00%), SP (91.30%), Ats/SP (88.90%) and quinine (53.80%) failure rates indicating wide spread circulation of poor quality antimalarial drugs in Malawi.Item Post-marketing surveillance of anti-malarial medicines used in Malawi(2015-03-25) Chikowe, I.; Osei-Safo, D.; Harrison, J.J.; Konadu, D.Y.; Addae-Mensah, I.Abstract Background The growing concern over the extent of anti-malarial medicine resistance in sub-Saharan Africa, driven largely by administration of sub-therapeutic doses derived from falsified and substandard medicines necessitates regular monitoring of the quality of these medicines to avert any potential public health disaster. This study aimed at determining the active pharmaceutical ingredient (API) content of anti-malarial medicines available in Malawi with respect to the manufacturers’ label claim and pharmacopoeia specifications. Methods Samples of anti-malarial medicines (112) collected from both licensed and unlicensed markets throughout Malawi were subjected to visual inspection of dosage form and packaging, and registration verification with the regulatory body. Basic (colourimetric) tests were employed to establish the presence and identity of the requisite APIs. Semi-quantitative thin layer chromatography (SQ-TLC) was employed as a quick assay for the verification of identity and estimation of the API content while HPLC assays were used to quantify the APIs. The results were compared with pharmacopoeia specifications and manufacturers’ label claims. For combination therapies, a sample was considered to have failed if one or more of its component APIs did not meet pharmacopoeia specifications. Results There was 86.6% registration status and 100% compliance with visual inspection and basic tests confirming the presence of requisite APIs. The identification test was confirmed by the SQ-TLC assay. API quantification by HPLC assay however, showed that 88.4% (99/112) of the samples failed the quality tests due to the presence of either insufficient or excessive API. Conclusions The results suggest the existence of substandard anti-malarial medicines in Malawi. The presence of both excessive and insufficient artemisinin-based and non-artemisinin-based API, clearly points to poor adherence to GMP and improper handling during storage or distribution. The country relies heavily on imported anti-malarial medicines so there is an urgent need to carry out regular and thorough post-market surveillance of medicines to ensure better quality health care delivery.Item Post-marketing surveillance of anti-malarial medicines used in Malawi(Malaria Journal, 2015-03) Chikowe, I.; Osei-Safo, D.; Harrison, J.J.E.K.; Konadu, D.Y.; Addae-Mensah, I.The growing concern over the extent of anti-malarial medicine resistance in sub-Saharan Africa, driven largely by administration of sub-therapeutic doses derived from falsified and substandard medicines necessitates regular monitoring of the quality of these medicines to avert any potential public health disaster. This study aimed at determining the active pharmaceutical ingredient (API) content of anti-malarial medicines available in Malawi with respect to the manufacturers’ label claim and pharmacopoeia specifications. Samples of anti-malarial medicines (112) collected from both licensed and unlicensed markets throughout Malawi were subjected to visual inspection of dosage form and packaging, and registration verification with the regulatory body. Basic (colourimetric) tests were employed to establish the presence and identity of the requisite APIs. Semi-quantitative thin layer chromatography (SQ-TLC) was employed as a quick assay for the verification of identity and estimation of the API content while HPLC assays were used to quantify the APIs. The results were compared with pharmacopoeia specifications and manufacturers’ label claims. For combination therapies, a sample was considered to have failed if one or more of its component APIs did not meet pharmacopoeia specifications. There was 86.6% registration status and 100% compliance with visual inspection and basic tests confirming the presence of requisite APIs. The identification test was confirmed by the SQ-TLC assay. API quantification by HPLC assay however, showed that 88.4% (99/112) of the samples failed the quality tests due to the presence of either insufficient or excessive API. The results suggest the existence of substandard anti-malarial medicines in Malawi. The presence of both excessive and insufficient artemisinin-based and non-artemisinin-based API, clearly points to poor adherence to GMP and improper handling during storage or distribution. The country relies heavily on imported anti-malarial medicines so there is an urgent need to carry out regular and thorough post-market surveillance of medicines to ensure better quality health care delivery. (PDF) Post-marketing surveillance of anti-malarial medicines used in Malawi. Available from: https://www.researchgate.net/publication/275027336_Post-marketing_surveillance_of_anti-malarial_medicines_used_in_Malawi [accessed Oct 22 2018].