Stanley N Ndwigah
University of Nairobi
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Publication
Featured researches published by Stanley N Ndwigah.
The Scientific World Journal | 2017
Lucia Keter; Richard Too; Nicholas Mwikwabe; Charles Mutai; Jennifer Orwa; Lizzy A. Mwamburi; Stanley N Ndwigah; Christine Bii; Richard Korir
Utilization of herbal products is a major concern due to the possibility of contamination by toxigenic fungi that are mycotoxin producers such as Aspergillus species during processing and packaging. Research was carried out to determine the presence of aflatoxins and fumonisins in herbal medicinal products sold in Eldoret and Mombasa towns in Kenya. The study employed both exploratory and laboratory experimental design. The herbal products were purchased from the market and transported to Kenya Medical Research Institute for processing and analysis. Fungal contaminants were determined according to Pharmacopoeia specifications. The toxins were quantified using ELISA based technique. The genus Aspergillus was the most dominant followed by Penicillium. Fungal counts ranged between 1 CFU/g and >1000 cfu/g. Analysis of variance showed that the rate of fungal contaminants for Eldoret and Mombasa samples had significant association (p ≤ 0.001). Aflatoxin levels ranged from 1 to 24 ppb, while fumonisin levels ranged from 1 to >20 ppb. Only 31% of samples met the standards for microbial limits as specified in Pharmacopoeia. There is need for product microbial quality improvement through proper harvesting, processing, storage, and marketing. It is recommended that a policy be enacted to enable regulation of herbal products in Kenya.
Malaria Journal | 2018
Stanley N Ndwigah; Andy Stergachis; Kennedy O. Abuga; Hn Mugo; Io Kibwage
BackgroundMalaria is a major health problem in sub-Saharan Africa where over 90% of the world’s malaria cases occur. Artemisinin-based combination therapy (ACT) is recommended by the World Health Organization as first-line and second-line treatments for uncomplicated falciparum malaria. However, there are a growing number of reports of sub-standard and falsified anti-malarial medicines in sub-Saharan Africa.MethodsA cross-sectional study was conducted in Embu County, Kenya on the quality of anti-malarial medicines available in public and private facilities. Sampling of anti-malarial medicines from public and private hospitals, health centers and pharmacies was conducted between May and June 2014. Quality control tests were performed at the Drug Analysis and Research Unit, University of Nairobi, using ultraviolet spectrophotometry and high-performance liquid chromatography. A test for microbial load was also conducted for suspension formulations.ResultsA total of 39 samples were collected from public and private facilities across the Embu County. A visual inspection of the medicines showed no signs of sub-standard or falsification. All ACT passed identification, assay and dissolution tests. Of 11 suspension samples collected, none failed the microbial load test although one sample had 50 colony forming units (cfu). No oral artemisinin monotherapy medicines were encountered during the survey. Amodiaquine and chloroquine monotherapy products accounted for 5% of the collected samples, despite their ban in Kenya. Two herbal anti-malarial formulations were collected during the survey. Sulfadoxine/pyrimethamine (SP) was also found to be available use for malaria treatment, not in accordance with malaria treatment guidelines.ConclusionAll the anti-malarial drugs analysed in this study passed the quality control tests. This is encouraging given the high malaria burden in Kenya. Regulatory actions are required to counter SP and herbal products for malaria treatment.
Pharmaceutics | 2017
Alex O. Okaru; Kennedy O. Abuga; F.N. Kamau; Stanley N Ndwigah; Dirk W. Lachenmeier
A simple, isocratic and robust RP-HPLC method for the analysis of azithromycin was developed, validated and applied for the analysis of bulk samples, tablets and suspensions. The optimum chromatographic conditions for separation were established as a mobile phase comprised of acetonitrile-0.1 M KH2PO4 pH 6.5–0.1 M tetrabutyl ammonium hydroxide pH 6.5-water (25:15:1:59 v/v/v/v) delivered at a flow rate of 1.0 mL/min. The stationary phase consisted of reverse-phase XTerra® (250 mm × 4.6 mm i.d., 5 µm particle size) maintained at a temperature of 43 °C with a UV detection at 215 nm. The method was found to be linear in the range 50%–150% (r2 = 0.997). The limits of detection and quantification were found to be 0.02% (20 µg) and 0.078% (78 µg), respectively, with a 100.7% recovery of azithromycin. Degradation products of azithromycin in acidic and oxidative environments at 37 °C were resolved from the active pharmaceutical ingredient and thus the method is fit for the purpose of drug stability confirmation.
Archive | 2008
Apollo Odhiambo Maima; Gn Thoithi; Stanley N Ndwigah; F.N. Kamau; Io Kibwage
The East and Central African Journal of Pharmaceutical Sciences | 2009
Apollo Odhiambo Maima; Gn Thoithi; Stanley N Ndwigah; F.N. Kamau; Io Kibwage
American Journal of Microbiology | 2016
Lucia Keter; Richard Too; Nicholas Mwikwabe; Stanley N Ndwigah; Jennifer Orwa; Elizabeth Mwamburi; Richard Korir; Charles Mutai
The East and Central African Journal of Pharmaceutical Sciences | 2013
Kennedy O. Abuga; Beatrice K Amugune; Stanley N Ndwigah; F.N. Kamau; Gn Thoithi; John O. Ogeto; Alex O. Okaru; Jm Nguyo; Ok King'ondu; Hn Mugo; Io Kibwage
East Cent. Afr. J. Pharm. Sci. | 2005
Gn Thoithi; Stanley N Ndwigah; Io Kibwage; J.W. Mwangi
The African Journal of Pharmacology and Therapeutics | 2017
Alice N Gichobi; Stanley N Ndwigah; Kipruto A. Sinei; Eric M. Guantai
The African Journal of Pharmacology and Therapeutics | 2017
Boniface M Thuo; Gn Thoithi; N Maingi; Stanley N Ndwigah; Rose N Gitari; Rebecca W Githinji; Richard O Otieno