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Possible nifedipine-digoxin interaction was investigated in rats by comparing lethal doses of intravenously infused digoxin in control and experimental rats. In the experimental rats, nifedipine was administered intraperitoneally, 30 minutes prior to infusing digoxin at a constant rate of 40mcg per minute. Results indicate that nifedipine administered within the dosage range 0.5-2.0mg per kg rat body weight, lowered the lethal dose of intravenously infused digoxin by 26-38% compared with control rats, thus indicating a synergistic effect between the two drugs. There was very little dose dependence of this effect. It is concluded that concomitant administration of nifedipine and digoxin in humans may lead to drug interactions.

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Contents of tetracycline, its degradation products (epitetracycline, epianhydrotetracycline, anhydrotetracycline) and a fermentation impurity (2-acetyl-2-decarboxamidotetracycline) were determined in four raw materials, 12 batches of six ointment products, four eye ointment products and nine batches of five capsule products, all sampled from the Kenyan market. The analytical method was liquid chromatography on a column packed with a poly(styrenedivinyl-benzene) material (8-microns PLRP-S 100 A). All raw materials and finished products had tetracycline contents and impurity levels within the prescribed compendial limits.

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During a 4 year period (January 1983 to December 1986), 418 requests for drug analysis were received in the Drug Analysis and Research Unit, Department of Pharmacy, University of Nairobi. Of these requests, 212 were from Medical Supplies Coordination Unit, 190 from Government hospitals and health research institutions, 11 from the Ministry of Health Headquarters (Director of Medical Services and Chief Pharmacist) and 5 came from local pharmaceutical manufacturers. Of the samples analysed, 70.8% were from local manufacturers, 26.1% were imported and 3.1% were from undeclared sources. Failure to comply with test for quality, as set out in official compendia (B.P. Eur. ph. Ip, etc.) were observed at 45.8% for locally manufactured drugs and 31.4% for imported drug products.

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A total of 41 samples of maternal blood, milk, subcutaneous fat and umbilical cord blood were collected from mothers giving birth by Caesarean operation at Kenyatta National Hospital in Nairobi in 1986. The samples were analyzed for organochlorine contaminants. The main contaminants found in all the samples were p,p'-DDT (100%), p,p'-DDE (100%), o,p'-DDT (59%), dieldrin (27%), transnonachlor (15%), beta-HCH (12%) and lindane (2%) of all the samples analyzed. Polychlorobiphenyl (PCB) residues were not detected in any of the samples. The mean levels (mg/kg fat) of sum of DDT were 5.9 in subcutaneous fat, 4.8 in mothers milk, 2.7 in maternal serum and 1.9 in umbilical cord serum. There was a significant correlation between the levels of sum DDT in subcutaneous fat and milk fat (r = 0.963), subcutaneous fat and maternal serum fat (r = 0.843), and maternal serum fat and maternal milk fat (r = 0.868), indicating the coherence of DDT in the body. Hexachlorocyclohexane (beta-HCH) was found in subcutaneous fat and milk fat with the mean levels of 0.03 and 0.26 mg/kg fat, respectively. Dieldrin detected in mothers milk and subcutaneous fat could not be quantified.

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One hundred and five chicken egg samples were taken from seven geographical locations in Kenya and analyzed for organochlorine pesticide residues using gas-liquid chromatography. Nine organochlorine compounds were detected: alpha- and gamma-HCH/BHC (hexachlorocyclohexane/benzene hexachloride), aldrin, dieldrin, p,p'-DDE [1,1-dichloro-2,2-bis(p-chlorophenyl)ethylene], p,p'-DDD (TDE) [2,2-bis(p-chlorophenyl)-1,1-dichloroethane] (tetrachlorodiphenylethane), o,p'-DDD [2-(o-chlorophenyl)-2-(p-chlorophenyl)-1,1-dichloroethane], o,p'-DDT [2-(o-chlorophenyl)-2-(p-chlorophenyl)-1,1,1-trichloroethane], and p,p'-DDT. Eighteen of the samples contained DDT levels exceeding the practical residue limit (0.5 ppm). The mean DDT residue content was 0.68 ppm, a result influenced greatly by the high contamination in the 18 samples. Both individual and mean residue levels for other organochlorine pesticides detected were well within the respective practical residue limits.

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One hundred and five chicken fat samples were collected between April, 1980 and February, 1982 from seven geographical locations in Kenya (15 samples/area). The samples were subjected to standard extraction and clean up procedures to recover organochlorine pesticides and were subsequently analysed using gas-liquid-chromatography. alpha-, beta-, and gamma-hexachlorocyclohexane/benzene hexachloride (HCH/BHC; Lindane), aldrin, dieldrin, heptachlor epoxide, [1,1-dichloro-2, 2-bis(p-chlorophenyl) ethylene] (p,p'-DDE), [2-(o-chlorophenyl)-2-(p-chlorophenyl)-1, 1-dichloroethane] (o,p'-DDD/TDE), p,p'-DDD, [2-(o-chlorophenyl)-2-(p-chlorophenyl)-1,1, 1-trichloroethane] (o,p'-DDT), and p,p'-DDT were detected in the samples in varying concentrations. A few samples had lindane, dieldrin, and total DDT residue levels above the respective practical residue limit (PRL) values, but for all pesticides, the mean residue values were below the PRL.

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Residue levels of the chlorinated hydrocarbons p,p'-DDT (2,2-bis(p-chlorophenyl)-1,1,1-trichloroethane), p,p'-DDE (2,2-bis(p-chlorophenyl)-1,1-dichloroethane), hexachlorobenzene (HCB), alpha-, beta-, and gamma-hexachlorocyclohexane (HCH), aldrin, dieldrin, and polychlorinated biphenyls (PCBs) were determined in human milk of Kenyan mothers living in different areas of Kenya. The main organochlorine contaminants found in all the milk samples analyzed were p,p'-DDT and p,p'-DDE. Great regional differences were found, and mean levels of sum DDT and DDT/DDE ratio ranged from 1.1 to 18.7 mg/kg milk fat and from 0.7 to 5.7, respectively. In general, relatively low residue levels of HCB, alpha-HCH, beta-HCH, aldrin, and dieldrin were detected in 59, 37, 27, 37, and 19%, respectively, of all the milk samples analyzed. Quantifiable residue levels of PCBs and alpha-HCH were not found. The results were examined in relation to differences in living conditions with regard to agricultural activities, dietary habits, and reported use of pesticides in the various sampling areas.

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Cathinone, a potent psychostimulant isolated from young shoots of Catha edulis was given to four human volunteers. Examination of urine collected from the volunteers at predetermined intervals showed the presence of unchanged cathinone, d-norpseudoephedrine, and two unidentified basic substances. The observed biotransformation of cathinone to the less potent psychostimulant, d-norpseudoephedrine involves reduction of a ketone group to alcohol, a common metabolic pathway in humans.

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