Bio

Personal information

Dr. Kennedy O. Abuga was born in 1972 in Nyamira County. He attended Biego Primary School, Sameta Secondary School before proceeding to the University of Nairobi wherefrom he graduated with a Bachelor of Pharmacy degree in 1996. He obtained a Master of Pharmacy (Pharmaceutical  Analysis) degree of the Katholieke Universiteit Leuven (KUL), Belgium in 2000. In 2009, Dr. Abuga was awarded PhD degree in Pharmaceutical Chemistry of the University of Nairobi. Dr. Abuga is currently the  Chair of the Department of Pharmaceutical Chemistry.

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Publications


2017

Okaru, AO, Abuga KO, Kamau FN, Ndwigah SN, Lachenmeier DW.  2017.  A Robust Liquid Chromatographic Method for Confirmation of Drug Stability of Azithromycin in Bulk Samples, Tablets and Suspensions. Pharmaceutics. 9(1):11. Abstract

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.

2016

Mukungu, NA, Abuga KO, Okalebo FO, Ingwela RT, Mwangi JW.  2016.  Medicinal plants used for management of malaria among the Luhya community of Kakamega East sub-County, Kenya. Journal of ethnopharmacology. 194 :98–107. Abstract

Background

Malaria remains a major health problem worldwide especially in sub-Saharan Africa. In Kenya, 80% of the population is at risk of contracting the disease. Pregnant mothers and children under five years are the most affected by this disease. Antimalarial drug resistance poses a major threat in the fight against malaria necessitating continuous search for new antimalarial drugs. Due to inadequate and inaccessible health facilities, majority of people living in rural communities heavily depend on traditional medicine which involves the use of medicinal plants for the management of malaria. Most of these indigenous knowledge is undocumented and risks being lost yet such information could be useful in the search of new antimalarial agents.

Aim of study

An ethnobotanical survey was carried out among the Luhya community of Kakamega East sub-County, a malaria epidemic region, with the aim of documenting the plants used in the management of malaria.

Materials and methods

Semi-structured questionnaires were used to collect information from 21 informants who included traditional medicine practitioners and other caregivers who had experience in use of plants in management of malaria. These were drawn from 4 villages located in Kakamega East sub-county, within Kakamega County based on their differences in topography. Information recorded included plant names, parts used, mode of preparation and administration and the sources of plant materials. A literature search was conducted using PubMed and google scholar to identify the reported traditional uses of these plants and studied antiplasmodial activities.

Results

In this study, 57% of the informants were aged above 50 years and a total of 61% had either no formal education or had only attained primary school education. A total of 42 plant species belonging to 24 families were identified. Most plants used in the management of malaria in this community belonged to Lamiaceae (18%), Leguminosae (9%) and Compositae (9%) plant families. Plants mostly used included Melia azedarach L, Aloe spp, Ajuga integrifolia Buch. Ham, Vernonia amygdalina Del., Rotheca myricoides (Hochst.) Steane and Mabb, Fuerstia africana T.C.E.Fr., Zanthoxylum gilletii (De Wild.) P.G.Waterman and Leucas calostachys Oliv. Rumex steudelii Hochst.ex A. Rich and Phyllanthus sepialis Müll. Arg are reported for the first time in the management of malaria. Although Clerodendrum johnstonii Oliv. ( Jeruto et al., 2011) and Physalis peruviana L.(Ramadan et al., 2015) are reported in other studies for management of malaria, no studies have been carried out to demonstrate their antiplasmodial activity.
The plant parts mostly used were the leaves (36%) and stem barks (26%). Majority of these plants were prepared as decoctions by boiling and allowed to cool before administration (66%) while infusions accounted for 28% of the preparations. The literature mined supports the use of these plants for the management of malaria since most of them have demonstrated in-vitro and in-vivo antiplasmodial activities.

Conclusion

Most of the reported plant species in this study have been investigated for antiplasmodial activity and are in agreement with the ethnomedical use. Two (2) plants are reported for the first time in the management of malaria. There is need for documentation and preservation of the rich ethnomedical knowledge within this community given that most of the practitioners are advanced in age and less educated. There is also the danger of over-exploitation of plant species as most of them are obtained from the wild, mainly Kakamega forest. Therefore, there is need for determining the economically and medicinally important plants in this community and planning for their preservation.

Njaria, PM, Abuga KO, Kamau FK, Chepkwony HK.  2016.  A versatile hplc method for the simultaneous determination of bromhexine, guaifenesin, ambroxol, salbutamol/terbutaline, pseudoephedrine, triprolidine, and chlorpheniramine maleate in cough–cold syrups. Chromatographia . 79(21):1507–1514. Abstract

A simple, rapid, isocratic, and versatile liquid chromatographic method was developed for the simultaneous
determination of bromhexine, guaifenesin, ambroxol, salbutamol/terbutaline, pseudoephedrine, triprolidine, and
chlorpheniramine maleate in cough–cold syrups commonly marketed in Kenya. Separation was achieved using
a Gemini® NX C18 column (250 × 4.6 mm, 5 μm) maintained at 40 °C and a mobile phase consisting of acetonitrile-0.25 M sodium hexanesulphonate-0.2 M ammonium acetate, and pH 3.0-water (35:4:10:51, % v/v/v/v) delivered at 1.0 mL min−1. The eluents were monitored by means of UV detection at 254 nm. During validation, the method satisfied the International Committee on Harmonization acceptance criteria for linearity, sensitivity, precision, accuracy, and robustness. The developed liquid chromatographic method was applied in the analysis of nine commercial samples obtained from Nairobi City County, Kenya. Extraction procedures were not applied during the assay of the samples, thus significantly shortening the analysis time.

2014

Gachangaga, PN, Amugune BK, Ogeto JO, Abuga KO.  2014.  A liquid chromatographic method for the simultaneous determination of amlodipine, valsartan and hydrochlorothiazide in tablets.. East Cent. Afr. J. Pharm.. 17(2):25-34. Abstract

A simple, rapid, sensitive, specific, accurate, precise and fast high performance liquid
chromatographic method for the determination of antihypertensive drugs amlodipine,
valsartan and hydrochlorothiazide singly or in combination was developed and
validated. Separation of the analytes was achieved on a Hypersil C-18 (250 mm × 4.6
mm, 5 μm) column using a mobile phase consisting of acetonitrile-KH2PO4 pH 3.0-
water (75:6:19 % v/v/v) delivered at 1 ml/min, UV detection at 229 nm and 40 oC
column temperature. The precision of the method was demonstrated through
repeatability (coefficient of variation = 0.298-0.724) as well as intermediate precision
(coefficient of variation = 0.435-1.412). The detector response was linear over the 25-
150 % range with R2 ≥ 0.99 for each of the three analytes. The limit of detection for
hydrochlorothiazide, valsartan and amlodipine were 10.72, 21.20 and 14.45 ng, while
the limits of quantification were 35.76, 71.23 and 48.16 ng, respectively. The method
showed satisfactory robustness and accuracy with a recovery of 99.7-100.6 %. The
method was applied in the assay of 6 commercial products containing drugs under
study. The results obtained revealed quality problems among the samples analyzed.

Muema, SM, Abuga KO, Yenesew A, Thoithi GN.  2014.  Phytochemical and Anthelmintic Study of the Root Bark of Teclea Trichocarpa, Engl. (Rutaceae). East Cent. Afr. J. Pharm.. 17(2):44-47. Abstract

The root bark of Teclea trichocarpa exhibited anthelmintic activity against egg hatching and larval development of sheep nematodes (Strongyloides). Three compounds, namely lupeol, melicopicine and 6-methoxytecleanthine were isolated from the dichloromethane-methanol (50:50) extract of the plant. Melicopicine and 6-methoxytecleanthine exhibited mild anthelmintic activity. The present study lends scientific credence to the traditional use of Teclea trichocarpa in the treatment of human helminth infections.

Okaru, AO, Abuga KO, Kamau FN, Ndwigah SN.  2014.  HPLC Analysis of Azithromycin Suspensions and Tablets, 16th May 2014. Optimizing medicine use to improve patient outcomes. , College of Health Sciences, UoN, Nairobi, Kenya

2013

Abuga, KO, Amugune BK, Ndwigah SN, Kamau FN, Thoithi GN, Ogeto JO, Okaru AO, Nguyo JM, King'ondu OK, Mugo HM, Kibwage IO.  2013.  Quality Performance of Drugs Analyzed in the Drug Analysis and Research Unit (DARU) during the Period 2006-2010. East Cent. Afr. J. Pharm. Sci.. 16(2):33-43. Abstract

During the period 2006-2010, the Drug Analysis and Research Unit analyzed 583 samples. The samples comprised 50.6% local and 49.4% imported products. Samples were subjected to compendial or in-house specifications. The failure rate was 12.2% for local products and 14.2% for imports. Antibacterial products recorded the highest failure rate (21.6%) while anticancers and drugs acting on the gastrointestinal, respiratory and reproductive systems all passed in the tests performed. The failure rate for antiprotozoals, antimalarials, antifungals, anthelminthics and analgesics was 14.3%, 12.5%, 11.8%, 8.9% and 11.5%, respectively.

Mukungu, NA, Abuga KO, Mungai NN, Karumi EW.  2013.  Isolation and structural elucidation of compounds from the non-alkaloidal extract of Nicandra physaloides and the antimicrobial activity of withanicandrin. East Cent. Afr. J. Pharm. . 16(2):49-53. Abstract

The aerial parts of Nicandra physaloides plant collected from Kenyatta National Hospital grounds were dried and subjected to acid-base extraction and partitioned to obtain alkaloidal and non-alkaloidal extracts. The non-alkaloidal extract yielded three compounds; withanicandrin, β-sitosterol and stigmasterol after column chromatography. Withanicandrin exhibited antifungal activity against Saccharomyces cerevisiae and Candida albicans but lacked antibacterial activity.

2009

  2009.  Ongarora D.S.B., Thoithi G.N., Kamau F.N., Abuga K.O., Mwangi J.W. and Kibwage I.O. Triterpenoids from the stem bark of Blighia unijugata Bak. (Sapindaceae). Ethiop. Pharm. J. . 24:71-74. Abstract

The structures of the two compounds were elucidated on the basis of their spectral data as friedelin and
epifriedelinol.

2008

  2008.  Thoithi G.N., Abuga K.O., Nguyo J.M., King’ondu O.K., Mukindia G.G., Mugo H.N., Ngugi J.K. and Kibwage I.O. Drug Quality Control in Kenya: Observation in the Drug Analysis and Research Unit During the period 2001-2005.. East Cent. Afr. J. Pharm. Sci.. 11(3):74-81. Abstract

During the five-year period January 2001 to December 2005, the Drug Analysis and
Research Unit received and analyzed 394 drug samples. Samples were received from
regulatory authorities, local industry, non-governmental organizations, hospitals
and private practitioners. The samples analyzed constituted 37.8 % locally
manufactured and 62.2 % imported products. In contrast to previous years when
failure rates of over 20 % were recorded, the overall rate of failure to comply with
compendial quality specifications was 6.1 %, comprising of 8.7 % locally
manufactured and 4.5 % imported drugs.

2003

Kuria, KAM, Abuga KO, Masengo W, Govaerts C, Roets E, Busson R, de Witte P, Zupko I, Hoornaert G, Hoogmartens J, Laekeman G.  2003.  In vitro Antimalarial Activity of Ajuga remota Benth (Labiatae). East Cent. Afr. J. Pharm. Sci.. 6(2):26-30. Abstract

Ajuga remota Benth is the most frequently used plant to treat malaria by Kenyan herbalists. Both crude extracts and pure isolates of the plant were tested for their in vitro antimalarial properties. The activity was assessed by an enzyme assay method based on the measurement of the parasite lactate dehydrogenase activity. The IC50 of the most active A. remota extract (ethanol macerate) was 71 and 69 μg/ml against the chloroquine sensitive (FCA/20GHA) and resistant (W2) strains of Plasmodium falciparum respectively. Ajugarin-1 was moderately active with IC50 of 23.0 ± 3.0 μM as compared to chloroquine (IC50 = 0.041 ± 0.003 μM) against the chloroquine-sensitive strain of Plasmodium falciparum. Ergosterol-5, 8-endoperoxide was about 4x as potent (IC50 = 5.4 ± 1.9 μM) while 8-0- acetylharpagide, a new isolate of A.remota and whose structure was established by spectroscopic evidence, was inactive.

  2003.  Abuga K.O., Mwagiru P.M., Thoithi G.N., Nguyo J.M., Ngugi J.K., King'ondu O.K., Mugo H.M. and Kibwage I.O. Quality of antiretroviral drugs analyzed in the Drug Analysis Research Unit during 2000-2003. East cent. Afr.J. Pharm. Sci.. 6(1):20-23.: Vaccine 26:2788- 2795 AbstractWebsite

During the period 2000-2003, the Drug Analysis and Research Unit received and analyzed 33 samples of antiretroviral drugs. Locally manufactured products accounted for 57.6% of the samples, while the imported drugs constituted 42.4%. The drugs consisted of single, double and triple component preparations. They were subjected to identity, assay and dissolution tests. 30 samples (90.9%) complied with compendial specifications for these tests, while 3 failed. The results obtained show that the manufacture of quality generic antiretroviral drugs is achievable.

2002

  2002.  G. N. Thoithi, K. O. Abuga, J. M. Nguyo, G. Mukindia, O. Kingondu, J. K. Ngugi and I. O. Kibwage, Drug quality control work in Drug Analysis and Research Unit: Observation during 1996-2000.. East Cent. Afr. J. Pharm. Sci.. 5(1):28-32.: Vaccine 26:2788- 2795 AbstractWebsite

The Drug Analysis and Research Unit received and analyzed 261 drug samples over a five-year period 1996 to 200. Samples were received from regulatory authorities, local industry, non-governmental organizations, hospitals and private practitioners. The samples analyzed constituted 59.8 % locally
manufactured and 40.2 % imported products. The overall rate of failure to comply with
quality specifications set out in the respective monographs was 21.1 %. This represents 24.6%
and 16.2 % of the locally manufactured imported drugs respectively.

  2002.  Maitai C.K., Njoroge D.K., Abuga K.O. , Mwaura A.M., Munenge R.W. Investigation of possible antidotal effects of activated charcoal, sodium bicarbonate, hydrogen peroxide and potassium permanganate in zinc phosphide poisoning. East Cent. Afr. J. Pharm. Sci. 5(2):38-41.: Vaccine 26:2788- 2795 AbstractWebsite

Zinc phosphide, a commonly used rat poison in Kenya was mixed with maize flour in a concentration of 0.15% w/w and fed to a group of 60 experimental mice for 3 hours. The mice were then randomly divided into 5 equal groups A, B, C, D and E. To groups A, B, C and D was administered activated charcoal (3% w/v), sodium bicarbonate (10% w/v), hydrogen peroxide(0.5% v/v) and potassium permanganate (1:5000) respectively. Group E was given 1 ml distilled water and used as control. All five groups were observed for symptoms of toxicity, often culminating in death. The observations were continued over a period of 36 hours. Results of the experiment showed that all for test substances minimized the lethal effect of zinc phosphide. Although no attempt was made to quantify the antidotal effect of the 4 substances, activated charcoal appeared to have a higher effect than the others, while potassium permanganate had a low rating.

2001

  2001.  Abuga K. O., Chepkwony H.K., Roets E., Hoogmartens J. A Stability-indicating HPLC method for the separation of clarithromycin and its related substances in bulk Samples. J. Sep. Sci.. 24:849-855.: Vaccine 26:2788- 2795 AbstractWebsite

Clarithromycin is a 6-O-methylated semi-synthetic derivative of erythromycin A,
which is more resistant towards acid decomposition. Commercial clarithromycin
samples contain several potential impurities arising from the manufacturing process
and degradation. A simple, selective, and sensitive isocratic liquid chromatographic
method has been developed for the impurity profiling of clarithromycin bulk samples.
The method employs a XTerra RP18, 5 lm, 25064.6 mm column thermostated at
568C. The mobile phase consists of acetonitrile ± 0.2 M potassium phosphate buffer
pH 6.80 ± water (40 : 3.5 :56.5). Several peaks are of unknown identity. The method
is stability indicating.

2000

1998

  1998.  Abuga K.O., Kokwaro G.O., Bosire K.O. Concomitant administration of theophylline and oxamniquine in rats: Effect on theophylline clearance. East Cent. Afr. J. Pharm. Sci. . 1(1):22-23.: Vaccine 26:2788- 2795 AbstractWebsite

This report describes an investigation into the effect of oxamniquine on systemic clearance of theophylline in rat. Male Wister rats (N=12, 5 weeks old) were divide into 3 groups (N=4 per group) and administered buffer plus theophylline (10 mg/kg), controls, oxamniquine( 5 mg/kg), and theophylline (10 mg/kg) oxamniquine (20 mg/kg) intravenously. Theophylline clearance was estimated from a single plasma sample obtained 6 hours post drug administration. Oxamniquine had no effect on theophylline clearance compared to controls. It was concluded that clinically important interaction between oxamniquine and theophylline is unlikely to occur.

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