Malie Rheeders

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OBJECTIVES Our objectives were to evaluate the contribution of bergamottin to the grapefruit juice-felodipine interaction and to characterize bergamottin disposition. METHODS In this study 250 mL grapefruit juice; 2-, 6-, or 12-mg capsules of bergamottin plus water; or water was administered with 5 mg extended-release felodipine to 11 volunteers in a(More)
The aim of this study was to quantify the plasma efavirenz concentrations over 6 months in black HIV-1-infected South African children (3-14 years), from resource-limited households, attending an outpatient clinic. The children were antiretroviral treatment (ART) naive and received efavirenz in combination with two nucleoside reverse transcriptase(More)
A novel and robust screening method for the determination of the non-nucleoside reverse transcriptase inhibitor, efavirenz (EFV), in human saliva has been developed and validated based on high performance liquid chromatography tandem mass spectrometry (LC-MS/MS). Sample preparation of the saliva involved solid-phase extraction (SPE) on C18 cartridges. The(More)
A selected group of poorly controlled epileptic patients had their drug plasma concentrations measured. Of those on a single drug, 33% were noncompliant, 33% had drug concentrations in the subtherapeutic or toxic ranges and 34% had levels in the therapeutic range, 86% of which were in the low therapeutic range. In only 9% of the group on multiple drugs were(More)
To investigate the influence of CYP2B6 516G>T polymorphism, as a covariate, and of interoccasion variability (IOV) on the oral clearance (CL/F) of efavirenz (EFV) in treatment-naïve black South African children over a period of 24 months post-antiretroviral therapy (ART) initiation. HIV-infected black children (n = 60, aged 3–16 years), with no prior(More)
The interaction between verapamil, a P-glycoprotein (P-gp) inhibitor, with ritonavir and lopinavir/ritonavir (LPV/r) after acute and chronic treatment was investigated in rats. Rats were divided into 4 groups, viz. Group 1: ritonavir, 20 mg/kg/d (n=18), group 2: ritonavir, 20 mg/kg/d plus verapamil 5 mg/kg/d (n=18), group 3: LPV/r, 80 and 20 mg/kg/d (n=17)(More)
In the routine care of 37 patients at the epilepsy outpatient clinic of Baragwanath Hospital, Johannesburg, 100 steady-state serum phenytoin concentrations were measured. Total and free phenytoin as well as albumin serum concentrations were determined. Computer analysed data were fitted to the Michaelis-Menten model for steady-state serum concentrations. As(More)
The absorption of theophylline from two commercial products labelled as having sustained-release properties (Theo-dur; Rio-Ethicals; and Euphyllin Retard; Byk-Gulden) was compared with that of a solution of theophylline (Alcophyllin syrup; Propan-Lipworth) in a multiple-dose study in smokers. As regards bioavailability, results for Theo-dur and Euphyllin(More)
South Africa has the highest burden of the human immunodeficiency virus (HIV) infection globally. Efavirenz (EFV), a frequently used drug against HIV infection, displays a relationship between drug concentration and pharmacodynamics effects clinically. However, haplotype-based genetic variation in drug metabolism in a pediatric sample has been little(More)
A simple, fast and cost-effective method was developed and validated for the determination of levetiracetam (LEV) in plasma/serum of patients using high performance liquid chromatography (HPLC) with ultraviolet detection. The stability of LEV plasma/serum samples over time and in different blood collection tubes was evaluated. Serum/plasma samples were(More)