Clinical Pharmacy & Administration
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Item Potential inhibition of major human cytochrome p450 isoenzymes by selected tropical medicinal herbs—implication for herb–drug interactions(2018) Showande S.J.; Fakeye T.O.; Kajula M.; Hokkanen J.; Tolonen A.Background: Increasing use of medicinal herbs as nutritional supplements and traditional medicines for the treatment of diabetes, hypertension, hyperlipidemia, and malaria fever with conventional drugs poses possibilities of herb–drug interactions (HDIs). The potential of nine selected widely used tropical medicinal herbs in inhibiting human cytochrome P450 (CYP) isoenzymes was investigated. Materials and methods: In vitro inhibition of eight major CYP isoenzymes by aqueous extracts of Allium sativum, Gongronema latifolium, Moringa oleifera, Musa sapientum, Mangifera indica, Tetracarpidium conophorum, Alstonia boonei, Bauhinia monandra, and Picralima nitida was estimated in human liver microsomes by monitoring twelve probe metabolites of nine probe substrates with UPLC/MS- MS using validated N- in- one assay method. Results: Mangifera indica moderately inhibited CYP2C8, CYP2B6, CYP2D6, CYP1A2, and CYP2C9 with IC50 values of 37.93, 57.83, 67.39, 54.83, and 107.48 μg/ml, respectively, and Alstonia boonei inhibited CYP2D6 (IC50 = 77.19 μg/ml). Picralima nitida inhibited CYP3A4 (IC50 = 45.58 μg/ml) and CYP2C19 (IC50 = 73.06 μg/ml) moderately but strongly inhibited CYP2D6 (IC50 = 1.19 μg/ml). Other aqueous extracts of Gongronema latifolium, Bauhinia monandra, and Moringa oleifera showed weak inhibitory activities against CYP1A2. Musa sapientum, Allium sativum, and Tetracarpidium conophorum did not inhibit the CYP isoenzymes investigated. Conclusion: Potential for clinically important CYP- metabolism- mediated HDIs is possible for Alstonia boonei, Mangifera indica, and Picralima nitida with drugs metabolized by CYP 2C8, 2B6, 2D6, 1A2, 2C9, 2C19, and 3A4. Inhibition of CYP2D6 by Picralima nitida is of particular concern and needs immediate in vivo investigations.Item In Vitro Modulation Of Cytochrome P450 Isozymes And Pharmacokinetics Of Caffeine By Extracts Of Hibiscus Sabdariffa Linn Calyx(2019) Showande S.J; Igbinoba S.I.; Kajula M.; Hokkanen J.; Tolonen A.; |Adegbolagun O.M.; Fakeye T.O.Background: Hibiscus sabdariffa beverage (HSB) is widely consumed as a medicinal herb and sometimes used concomitantly with drugs. This study evaluated the in vitro inhibitory potential of the aqueous extract of H. sabdariffa calyces (AEHS) on selected cytochrome P450 (CYP) isozymes and the effect of HSB on the pharmacokineticsofcaffeineinvivo. Methods:InvitroinhibitionsofeightmajorCYPisozymesbyAEHSwereestimatedbymonitoringCYP-specific modelreactionsof10CYPprobesubstratesusingN-in-oneassaymethod.Subsequently,anopen,randomized, two-periodcrossoverdesignwasusedtoevaluatetheeffectofHSBonthepharmacokineticsofsingle-dose200 mg caffeine in six healthy human volunteers. Blood samples were obtained at specific times over a 24 h period. Probe drugs and metabolites were analyzed in their respective matrices with ultra-performance liquid chromatography/mass spectrometer/mass spectrometer and reversed-phase high-performance liquid chromatography/ultravioletdetection. Results:TheH.sabdariffaaqueousextractweaklyinhibitedtheselectedCYPisozymesinvitro,withIC50of >100 μgmL-1 intheorderofCYP1A2>CYP2C8>CYP2B6»CYP2D6>CYP2C19>CYP3A4>CYP2A6>CYP2C9. HSBdecreasedterminalt1/2andTmaxofcaffeineby13.6%and13.0%,respectively,andincreasedCmaxby10.3%. Pointestimatesofprimarypharmacokineticendpoints,Cmax=1.142(90%confidenceinterval(CI)=0.882,1.480) andAUC0–∞=0.992(90%CI=0.745,1.320),wereoutsidethe90%CIof0.8–1.25bioequivalencelimits. Conclusion:TheaqueousextractofH.sabdariffaweaklyinhibitedeightCYPisozymesinvitro,butHSBmodified theexposuretocaffeineinhuman.CautionshouldbeexercisedinadministeringHSBwithcaffeineorsimilar substratesofCYP1A2untilmoreclinicaldataareavailable.Item Effects of Coadministration of Extract of Carica(2007-03) Fakeye T.O.; Oladipupo T.; Showande O; Ogunremi Y.Purpose: To investigate the interacting effects of co-administration of Carica papaya leaf extract on the hypoglycemic activity of metformin and glimepiride in an animal model. Method: Experimental factorial design was used to evaluate the individual and interaction influence of three variables ie nature (N), dose administered (C) and duration of administration (D), in a 23(=8) employed at two levels - ‘’high’’ and ‘‘low’’ - on blood glucose of diabetic rats on administration of ethanolic leaf extract of Carica papaya and two hypoglycemic agents, metformin and glimepiride.Unpaired t-test was used to test for significant difference due to administration of the combination Results: Extract of Carica papaya at 5.0 mg/kg produced significant blood glucose reduction with no significant reduction at the higher dose of 10 mg/kg (p>0.05). Changing nature from “low” (Carica papaya extract) to “high” (glimepiride or metformin) did not significantly change hypoglycemic activity.Generally, the ranking of the interacting effects was ND>CD>>NC for glimepiride/extract, and CD>ND>NC for metformin/extract. Administration of higher dose of the extract led to significant (p<0.01) increase in onset of activity of glimepiride. The onset of activity of metformin was not affected, but a significant lowering (p<0.05) of blood glucose was observed at 24 hr with all combinations of extract and metformin. Conclusion: Leaf extract of Carica papaya significantly delays the onset of hypoglycaemic activity of glimepiride, and increases the hypoglycaemic effect of metformin with the variables interacting differently for each drug-extract combinationsItem Assessment of compliance to treatment among ambulatory asthmatic patients in a secondary health care facility in nigeria(2012) Obasan A.A.; Showande S.J.; Fakeye T.O.This study assessed the level of compliance using three different methods: pill count, self report and peak expiratory flow rate, in asthmatic patients attending a secondary health care facility. Self report (using a pre-tested structured questionnaire), peak expiratory flow rate and pill count were used to assess patient’s compliance and identify the factors which may be responsible for non compliance. Measurement of peak expiratory flow rate and the pill count were done at two different occasions. The data obtained was analysed using descriptive statistics. The study showed that the patients were prescribed a range of one to four drugs: 54% (3 drugs), 32% (2 drugs), 8% (4 drugs) and 2% (1 drug). The levels of compliance were 86.57% for self report and 83.56% for pill count (p > 0.05). Reasons given for non compliance were: apparent wellness (33.31%), forgetfulness (26.67%), cost of drugs (6.67%), dysphagia (6.67%), presence of non-disturbing symptoms (6.67%), side effects (6.67%), ignorance/fear of addiction (6.67%), perceived lack of benefit from treatment (6.67%), and lethargy towards chronic medication (6.67%). However, there was a significant difference in the readings of the peak expiratory flow rate measured at two different occasions (p < 0.05). The study showed no significant difference in the methods used to assess the level of compliance. Non compliance can be overcome by proper education of patients on the importance of complying with the administration of medication and proper usage of metered dose devices.