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Na-Bangchang K, Guirou EA, Cheomung A, Karbwang J. Determination of Primaquine in Whole Blood and Finger-Pricked Capillary Blood Dried on Filter Paper Using HPLC and LCMS/MS. Chromatographia 2014. [DOI: 10.1007/s10337-014-2639-3] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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Sultana N, Arayne MS, Nawaz M, Rehman ZU. Liquid chromatographic analysis of halofantrine from dosage form and its metal interaction studies. Med Chem Res 2010. [DOI: 10.1007/s00044-010-9346-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Barnes KI, Lindegardh N, Ogundahunsi O, Olliaro P, Plowe CV, Randrianarivelojosia M, Gbotosho GO, Watkins WM, Sibley CH, White NJ. World Antimalarial Resistance Network (WARN) IV: clinical pharmacology. Malar J 2007; 6:122. [PMID: 17822537 PMCID: PMC2014777 DOI: 10.1186/1475-2875-6-122] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2007] [Accepted: 09/06/2007] [Indexed: 12/15/2022] Open
Abstract
A World Antimalarial Resistance Network (WARN) database has the potential to improve the treatment of malaria, through informing current drug selection and use and providing a prompt warning of when treatment policies need changing. This manuscript outlines the contribution and structure of the clinical pharmacology component of this database. The determinants of treatment response are multi-factorial, but clearly providing adequate blood concentrations is pivotal to curing malaria. The ability of available antimalarial pharmacokinetic data to inform optimal dosing is constrained by the small number of patients studied, with even fewer (if any) studies conducted in the most vulnerable populations. There are even less data relating blood concentration data to the therapeutic response (pharmacodynamics). By pooling all available pharmacokinetic data, while paying careful attention to the analytical methodologies used, the limitations of small (and thus underpowered) individual studies may be overcome and factors that contribute to inter-individual variability in pharmacokinetic parameters defined. Key variables for pharmacokinetic studies are defined in terms of patient (or study subject) characteristics, the formulation and route of administration of the antimalarial studied, the sampling and assay methodology, and the approach taken to data analysis. Better defining these information needs and criteria of acceptability of pharmacokinetic-pharmacodynamic (PK-PD) studies should contribute to improving the quantity, relevance and quality of these studies. A better understanding of the pharmacokinetic properties of antimalarials and a more clear definition of what constitutes "therapeutic drug levels" would allow more precise use of the term "antimalarial resistance", as it would indicate when treatment failure is not caused by intrinsic parasite resistance but is instead the result of inadequate drug levels. The clinical pharmacology component of the WARN database can play a pivotal role in monitoring accurately for true antimalarial drug resistance and promptly correcting sub-optimal dosage regimens to prevent these contributing to the emergence and spread of antimalarial resistance.
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Affiliation(s)
- Karen I Barnes
- Division of Clinical Pharmacology, Department of Medicine, University of Cape Town, Cape Town, South Africa
| | - Niklas Lindegardh
- Mahidol Oxford Research Unit, Faculty of Tropical Medicine, Mahidol University. Bangkok Thailand
- Nuffield Department of Medicine, University of Oxford, Oxford, UK
| | - Olumide Ogundahunsi
- UNICEF/UNDP/WB/WHO Special Programme for Research & Training in Tropical Diseases, World Health Organisation, Geneva, Switzerland
| | - Piero Olliaro
- UNICEF/UNDP/WB/WHO Special Programme for Research & Training in Tropical Diseases, World Health Organisation, Geneva, Switzerland
| | | | | | - Grace O Gbotosho
- Department of Pharmacology and Therapeutics, College of Medicine, University of Ibadan, Ibadan, Nigeria
| | | | - Carol H Sibley
- Department of Genome Sciences, University of Washington, Seattle, WA, USA
| | - Nicholas J White
- Mahidol Oxford Research Unit, Faculty of Tropical Medicine, Mahidol University. Bangkok Thailand
- Nuffield Department of Medicine, University of Oxford, Oxford, UK
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Leite EA, Grabe-Guimarães A, Guimarães HN, Machado-Coelho GLL, Barratt G, Mosqueira VCF. Cardiotoxicity reduction induced by halofantrine entrapped in nanocapsule devices. Life Sci 2007; 80:1327-34. [PMID: 17303179 DOI: 10.1016/j.lfs.2006.12.019] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2005] [Revised: 10/28/2006] [Accepted: 12/19/2006] [Indexed: 11/28/2022]
Abstract
The main objective of the present study was to evaluate the reduction in halofantrine (Hf) toxicity, an antimalarial drug frequently associated with QT interval prolongation in electrocardiogram, by its entrapment in poly-epsilon-caprolactone nanocapsules (NC). The acute lethal dose (LD(100)) of Hf.HCl experimentally observed was 200 mg/kg whereas the calculated LD(50) was 154 mg/kg. In contrast, the LD(100) for Hf-NC was 300 mg/kg with a longer mean time to death than Hf.HCl. The calculated LD(50) was 249 mg/kg for Hf-NC. The Hf entrapped in PCL NC presented a greater efficacy than PLA-PEG NC and than Hf solution in P. berghei-infected mice at 1 mg/kg. The cardiovascular parameters, ECG and arterial blood pressure, were evaluated in anaesthetized Wistar rats after the IV administration of a single, especially high dose (100 and 150 mg/kg) of halofantrine base loaded-nanocapsules (Hf-NC) or halofantrine chlorhydrate (Hf.HCl) solution. It was observed that Hf solution caused prolongation of the QT and PR intervals of the ECG; however, this effect was significantly (P<0.001) reduced when Hf was administered entrapped in nanocapsules. The treatment with Hf.HCl induced a pronounced bradycardia and severe hypotension leading to death. The effect of Hf-NC upon heart rate was reduced from 58 to 75% for 100 and 150 mg/kg, respectively, when compared with Hf.HCl solution. These findings show that the encapsulation of halofantrine reduces the QT interval prolongation of ECG in rats and suggest that a modification of drug distribution was possible by using nanocapsules. Hf encapsulation was the main factor responsible for the significant reduction in cardiac toxicity observed.
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Affiliation(s)
- Elaine Amaral Leite
- Núcleo de Pesquisa em Ciências Biológicas, ICEB, Universidade Federal de Ouro Preto, Ouro Preto, Minas Gerais, Brazil
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Kolade YT, Babalola CP, Scriba GKE. Analysis of the antimalarial drug halofantrine and its major metabolite N-desbutylhalofantrine in human plasma by high performance liquid chromatography. J Pharm Biomed Anal 2006; 41:315-9. [PMID: 16337357 DOI: 10.1016/j.jpba.2005.11.002] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2005] [Revised: 11/03/2005] [Accepted: 11/03/2005] [Indexed: 11/22/2022]
Abstract
The determination of halofantrine and its major metabolite N-desbutylhalofantrine in human plasma by reversed phase high-pressure liquid chromatography is described. The method involves protein precipitation of plasma samples by acetonitrile followed by basification with sodium hydroxide and subsequent liquid-liquid extraction using hexane-diethyl ether (1:1, v/v). The chromatographic separation was carried out on a C-18 column with a mobile phase consisting of methanol/0.05 M KH2PO4 (78:22, v/v) containing 55 mM perchloric acid. Chlorprothixen was used as internal standard. The relative standard deviations of intraday and interday precision for both compounds were less than 7%, the relative standard deviation of the accuracy did not exceed 7.1% at concentrations of 50 and 300 ng/ml. This method is simple, rapid, sensitive and cost effective and was applied to the determination of the pharmacokinetics of halofantrine and N-desbutylhalofantrine in two healthy male volunteers after an oral administration of 500 mg halofantrine. Moreover, the influence of the frequently consumed kolanut on the pharmacokinetics of halofantrine was investigated.
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Affiliation(s)
- Yetunde T Kolade
- Department of Pharmaceutical Chemistry, School of Pharmacy, University of Jena, Philosophenweg 14, 07743 Jena, Germany
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6
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Mosqueira VCF, Loiseau PM, Bories C, Legrand P, Devissaguet JP, Barratt G. Efficacy and pharmacokinetics of intravenous nanocapsule formulations of halofantrine in Plasmodium berghei-infected mice. Antimicrob Agents Chemother 2004; 48:1222-8. [PMID: 15047523 PMCID: PMC375247 DOI: 10.1128/aac.48.4.1222-1228.2004] [Citation(s) in RCA: 71] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The efficacy and pharmacokinetics of a new parenteral formulation of halofantrine were studied in mice infected with Plasmodium berghei. The formulation consisted of nanocapsules with an oily core, prepared from either poly(D,L-lactide) (PLA) homopolymer or PLA that was surface modified with grafted polyethylene glycol chains. They were compared with a previously described intravenous halofantrine preparation. No toxic effects were observed with halofantrine in form of nanocapsules after intravenous administration for doses of up to 100 mg/kg, whereas the solubilized form in polyethylene glycol-dimethylacetamide was toxic at this dose. The halofantrine-loaded nanocapsules showed activity that was similar to or better than that of the solution in the 4-day test and as a single dose in severely infected mice, with only minimal differences between the two nanocapsule formulations. Halofantrine pharmacokinetics were determined in parallel with parasite development in severely infected mice. Nanocapsules increased the area under the curve for halofantrine in plasma more than sixfold compared with the solution throughout the experimental period of 70 h. Furthermore, nanocapsules induced a significantly faster control of parasite development than the solution in the first 48 h posttreatment. While the parasitemia fell more rapidly with PLA nanocapsules, the effect was more sustained with the surface-modified ones. This is consistent with surface-modified nanocapsules remaining longer in the circulation. These results suggest that nanocapsule formulations could provide a more favorable halofantrine profile in the plasma and reduce the intravenous dose necessary and therefore the toxicity, thus suggesting the use of halofantrine by a parenteral route in severe malaria.
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Affiliation(s)
- Vanessa C F Mosqueira
- UMR CNRS 8612 and BIOCIS, UPRES A CNRS 8076, Faculté de Pharmacie, Université de Paris-Sud, 92296 Châtenay Malabry, France
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7
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Lightbown ID, Lambert JP, Edwards G, Coker SJ. Potentiation of halofantrine-induced QTc prolongation by mefloquine: correlation with blood concentrations of halofantrine. Br J Pharmacol 2001; 132:197-204. [PMID: 11156578 PMCID: PMC1572561 DOI: 10.1038/sj.bjp.0703823] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
1. The antimalarial drug halofantrine can prolong the QT interval and this may be enhanced by prior use of mefloquine. This possible interaction has been investigated by examining the effects of halofantrine and mefloquine alone and in combination. 2. In anaesthetized rabbits (n=6 per group), halofantrine given as bolus doses of 1, 3, 10, and 30 mg kg(-1) at 25 min intervals dose-dependently prolonged the rate-corrected QT (QTc) interval from 313+/-12 ms pre-drug to 410+/-18 ms after the highest dose. Similar doses of mefloquine did not alter QTc intervals significantly. The highest dose of mefloquine (30 mg kg(-1)) caused cardiac contractile failure. 3. Pretreatment with 3 mg kg(-1) mefloquine 25 min before the first dose of halofantrine potentiated the effects of all doses of halofantrine on QTc intervals. 4. The blood concentrations of halofantrine were two to six times higher in the group pretreated with mefloquine compared to the halofantrine alone group; e.g. 1.03+/-0.17 and 0.16+/-0.02 microM respectively after 1 mg kg(-1) halofantrine. There was a significant correlation between blood halofantrine concentrations and QTc intervals (r=0.673). Even after making allowance for overestimation of the potency of halofantrine that may result from the hypokalaemia that is prevalent in anaesthetized rabbits, these effects occurred with concentrations of halofantrine that are found in clinical use. 5. These data indicate clearly that while mefloquine does not alter QTc intervals itself, it does enhance the effects of halofantrine by increasing the circulating concentration of halofantrine.
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Affiliation(s)
- Ian D Lightbown
- Department of Pharmacology and Therapeutics, The University of Liverpool, Ashton Street, Liverpool L69 3GE
| | - James P Lambert
- Department of Pharmacology and Therapeutics, The University of Liverpool, Ashton Street, Liverpool L69 3GE
| | - Geoffrey Edwards
- Department of Pharmacology and Therapeutics, The University of Liverpool, Ashton Street, Liverpool L69 3GE
- Division of Parasite and Vector Biology, Liverpool School of Tropical Medicine, Liverpool L3 5QA
| | - Susan J Coker
- Department of Pharmacology and Therapeutics, The University of Liverpool, Ashton Street, Liverpool L69 3GE
- Author for correspondence:
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Malvy D, Receveur MC, Ozon P, Djossou F, Le Metayer P, Touze JE, Longy-Boursier M, Le Bras M. Fatal cardiac incident after use of halofantrine. J Travel Med 2000; 7:215-6. [PMID: 11003738 DOI: 10.2310/7060.2000.00065] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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9
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Hombhanje FW. Effect of a single oral dose of Fansidar on the pharmacokinetics of halofantrine in healthy volunteers: a preliminary report. Br J Clin Pharmacol 2000; 49:283-4. [PMID: 10718786 PMCID: PMC2014926 DOI: 10.1046/j.1365-2125.2000.00142.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
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10
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Gorichon E, Martin C, Bangchang KN, Karbwang J, Thuillier A, Farinotti R, Gimenez F. Chiral chromatographic method to determine the enantiomers of halofantrine and its main chiral desbutyl metabolite in erythrocytes. JOURNAL OF CHROMATOGRAPHY. B, BIOMEDICAL SCIENCES AND APPLICATIONS 1998; 712:259-62. [PMID: 9698249 DOI: 10.1016/s0378-4347(98)00151-0] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We describe a direct liquid chromatographic method with spectrofluorimetric detection to quantify the two enantiomers of halofantrine and the two enantiomers of its main chiral N-monodesbutylated metabolite in erythrocyte pellets. The method involves a Chiralpak AD column and a rapid one-step extraction procedure with acetonitrile. The method was validated for the four enantiomers within the range 0-1000 ng/ml. The absence of stereoconversion was studied in samples stored frozen for up to eight months. The optical rotation of the halofantrine and metabolite enantiomers was determined after separation on a semi-preparative Chiralcel OD column with polarimetric detection.
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Affiliation(s)
- E Gorichon
- Hôpital Pitié Salpêtrière, Service Pharmacie-Pharmacocinétique, Paris, France
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11
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Onyeji CO, Aideloje SO. Ion-pair reversed-phase high-performance liquid chromatographic analysis of halofantrine and desbutylhalofantrine in human plasma. Ther Drug Monit 1997; 19:682-7. [PMID: 9421111 DOI: 10.1097/00007691-199712000-00013] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
A new ion-pair reversed-phase high-performance liquid chromatographic (HPLC) method for the simultaneous measurements of halofantrine (HF) and its major metabolite, desbutylhalofantrine (Hfm), in human plasma is described. Sample treatment involved protein precipitation with acetonitrile followed by extraction with hexane-diethylether (ratio, 1:1; vol/vol) under alkaline condition. Chromatographic separation was achieved on a 10-microm particle size C-18 column (200 x 4.6 mm internal diameter) using a mobile phase consisting of methanol-0.05 M potassium dihydrogen phosphate (70:30, vol/vol) with 55 mmol/l perchloric acid (pH 3.1). Retention times for Hfm, Hf, and the internal standard were 5.3, 7.5, and 11.5 minutes, respectively. Detection limits of Hf and Hfm were 2.5 and 2.0 ng/ml, respectively (1 ng/ml = 2 nmol/l for Hf; 1 ng/ml = 2.25 nmol/l for Hfm). Intraassay and interassay coefficients of variation for both compounds were less than 7%, with an accuracy of no greater than 8% at concentrations of 40 and 400 ng/ml, respectively. The new HPLC method is sensitive, selective, and rapid. Relative to previous HPLC methods, it is simple and cost-effective. In addition, the internal standard is readily accessible. Application of this method in pharmacokinetic studies was demonstrated.
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Affiliation(s)
- C O Onyeji
- Department of Pharmaceutical Chemistry, Faculty of Pharmacy, Obafemi Awolowo University, Ile-Ife, Nigeria
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12
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Batey AJ, Lightbown ID, Lambert JP, Edwards G, Coker SJ. Comparison of the acute cardiotoxicity of the antimalarial drug halofantrine in vitro and in vivo in anaesthetized guinea-pigs. Br J Pharmacol 1997; 122:563-9. [PMID: 9351516 PMCID: PMC1564961 DOI: 10.1038/sj.bjp.0701402] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
1. Several unrelated drugs have pro-arrhythmic activity associated with an ability to prolong the QT interval of the ECG. The aim of this work was to examine the effects of the antimalarial drug halofantrine in vivo and in vitro. 2. In anaesthetized guinea-pigs consecutive bolus doses of halofantrine (0.3, 1, 3, 10 and 30 mg kg(-1), i.v.) at 25 min intervals caused dose-dependent prolongation of the rate corrected QTc interval and bradycardia. The change in heart rate became significant after administration of 10 mg kg(-1) halofantrine (-23+/-9 beats min[-1]) whereas the increase in QTc was significant with only 1 mg kg(-1) halofantrine (22+/-10 ms). It was only with the highest dose of halofantrine that the PR interval was increased (from 52+/-3 to 67+/-4 ms) and second degree atrioventricular (AV) block (type 1 Mobitz) occurred in all animals. No changes were observed in any parameters in a separate group of guinea-pigs which received vehicle (dimethylacetamide 60% propylene glycol 40%) at equivalent time points. 3. The blood concentrations of halofantrine ranged from 0.26+/-0.17 microM after administration of 0.3 mg kg(-1) to 2.79+/-0.87 microM after 30 mg kg(-1), i.v. There was a significant correlation between the blood concentrations of halofantrine and the changes in QTc interval. 4 In guinea-pig left papillary muscles the effective refractory period was increased significantly 60 min after addition of halofantrine; from 161+/-4 to 173+/-6 ms with 10 microM, 156+/-8 to 174+/-6 ms with 30 microM and 165+/-6 to 179+/-5 ms with 100 microM halofantrine. However, the vehicle (0.1% Tween 80 in DMSO; final concentration of vehicle in Krebs, 1%) also increased the effective refractory period from 164+/-5 to 173+/-6 ms. Similar results were obtained in right ventricular strips but left atrial effective refractory periods were not altered by either the vehicle or halofantrine. 5. The results of these experiments suggest that any direct effects that halofantrine may have had on the effective refractory period of cardiac muscle cannot be separated from those of the vehicle. The prolongation of QTc and consistent observation of AV block with halofantrine in anaesthetized guinea-pigs suggest that in vivo models may be more useful for further studies investigating the mechanisms underlying the cardiotoxicity of halofantrine.
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Affiliation(s)
- A J Batey
- Department of Pharmacology and Therapeutics, The University of Liverpool
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13
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Gundersen SG, Rostrup M, von der Lippe E, Platou ES, Myrvang B, Edwards G. Halofantrine-associated ventricular fibrillation in a young woman with no predisposing QTc prolongation. SCANDINAVIAN JOURNAL OF INFECTIOUS DISEASES 1997; 29:207-8. [PMID: 9181664 DOI: 10.3109/00365549709035889] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Affiliation(s)
- S G Gundersen
- Department of Infectious Diseases, Ullevaal Hospital, University of Oslo, Norway
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14
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Communications. Br J Pharmacol 1996. [DOI: 10.1111/j.1476-5381.1996.tb17246.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022] Open
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15
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Halliday RC, Jones BC, Smith DA, Kitteringham NR, Park BK. An investigation of the interaction between halofantrine, CYP2D6 and CYP3A4: studies with human liver microsomes and heterologous enzyme expression systems. Br J Clin Pharmacol 1995; 40:369-78. [PMID: 8554939 PMCID: PMC1365156 DOI: 10.1111/j.1365-2125.1995.tb04559.x] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
1. We have assessed the interaction of the antimalarial halofantrine with cytochrome P450 (CYP) enzymes in vitro, with the use of microsomes from human liver and recombinant cell lines. 2. Rac-halofantrine was a potent inhibitor (IC50 = 1.06 microM, Ki = 4.3 microM) of the 1-hydroxylation of bufuralol, a marker for CYP2D6 activity. Of a group of structurally related antimalarials tested, only quinidine (IC50 = 0.04 microM) was more potent. 3. Microsomes prepared from recombinant CYP2D6 and CYP3A4 cell lines were shown to catalyse halofantrine N-debutylation. 4. The metabolism of halofantrine to its N-desbutyl metabolite by human liver microsomes showed no correlation with CYP2D6 genotypic or phenotypic status and there was no consistent inhibition by quinidine. 5. The rate of halofantrine metabolism showed a significant correlation with both CYP3A4 protein levels (r = 0.88, P = 0.01) and the rate of felodipine metabolism (r = 0.86, P = 0.013), a marker substrate for CYP3A4 activity. Inhibition studies showed that ketoconazole is a potent inhibitor of halofantrine metabolism (IC50 = 1.57 microM). 6. In conclusion, we have demonstrated that halofantrine is a potent inhibitor of CYP2D6 in vitro and can also be metabolised by the enzyme. However, in human liver microsomes it appears to be metabolised largely by CYP3A4.
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Affiliation(s)
- R C Halliday
- Department of Pharmacology and Therapeutics, University of Liverpool, UK
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16
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Gaillard Y, Prévosto JM, Cheminel V, Soares O, Chaulet JF. New solid-phase extraction for an improved high-performance liquid chromatographic procedure for the quantitation of halofantrine and monodesbutylhalofantrine in blood or plasma. JOURNAL OF CHROMATOGRAPHY. B, BIOMEDICAL APPLICATIONS 1995; 668:315-21. [PMID: 7581867 DOI: 10.1016/0378-4347(95)00075-t] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
A rapid, accurate, and sensitive high-performance liquid chromatographic (HPLC) method, with fluorimetric detection, for the simultaneous measurement of halofantrine and desbutylhalofantrine in human plasma or whole blood is described. Sample preparation involved protein precipitation, followed by an efficient solid-phase extraction on a C8 cartridge. Analytes were isolated from 1 ml of the biological fluids and recovered by a 2% acetic acid in ethyl acetate solution. Chromatographic separation was carried out on a LiChrospher 60 RP select B, C8 bonded phase (5 microns particle size, 25 cm x 4 mm I.D.) using a mobile phase of water-acetonitrile (35:65, v/v) containing triethylamine (1%) and adjusted to pH 4 with orthophosphoric acid. The total run time was 14 min. Relative standard deviations of the intra-and inter-assay precisions were less than 5.9%. Assumption of linearity was investigated by studying the y-residuals and by ANOVA (analysis of variance). Because of the wide range of calibration (0.1 to 2.0 microgram/ml) variances were non-homogeneous (Hartley's test) and the weighted regression line was computed in order to allow pharmacokinetic studies. Accuracy was tested using a t-statistic. Limits of decision, detection and quantification were realized from an analysis of the blanks. Application of the method to clinical specimens was demonstrated.
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Affiliation(s)
- Y Gaillard
- Laboratoire de Biochimie, Pharmacologie et Toxicologie du Pr. Blanchot, Hôpital d'Instruction des Armées Desgenettes, Lyon, France
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17
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Cenni B, Meyer J, Brandt R, Betschart B. The antimalarial drug halofantrine is bound mainly to low and high density lipoproteins in human serum. Br J Clin Pharmacol 1995; 39:519-26. [PMID: 7669488 PMCID: PMC1365059 DOI: 10.1111/j.1365-2125.1995.tb04489.x] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
1. The major serum proteins which bind halofantrine were identified by size exclusion chromatography. In addition, the binding affinity of halofantrine to human erythrocytes and serum proteins was measured by an erythrocyte partitioning technique. The influence of serum-drug binding on the distribution of halofantrine in whole blood was estimated by simulating several disease-related changes in the levels of the most important binding proteins. 2. The chromatographic resolution of serum preincubated with halofantrine allowed a quantitative analysis of binding to low density lipoproteins, high density lipoproteins, alpha 1-acid glycoprotein and albumin using the erythrocyte partitioning technique. Very low density lipoproteins did not bind halofantrine to a significant extent. 3. In whole blood halofantrine is bound to serum proteins (83%) and to erythrocytes (17%). Low density lipoproteins (affinity constant nKP = 44.4 l g-1) and high density lipoproteins (nKP = 14.4 l g-1) were the most important binding proteins in serum. alpha 1-acid glycoprotein (nKP = 4.39 l g-1) and albumin (nKP = 0.27 l g-1) had relatively low binding affinities. 4. The concentration of serum proteins influences both the fraction of unbound drug and the fraction of drug associated with the erythrocytes. Changes in serum protein concentrations often encountered in malaria are likely to increase both the unbound fraction and the fraction bound to the erythrocytes.
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Affiliation(s)
- B Cenni
- Department of Medical Parasitology, Swiss Tropical Institute, Basel
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18
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Watkins WM, Winstanley PA, Mberu EK, Kokwaro G, Murphy SA, Newton CJ, Mwangi I, Forster D, Marsh K. Halofantrine pharmacokinetics in Kenyan children with non-severe and severe malaria. Br J Clin Pharmacol 1995; 39:283-7. [PMID: 7619670 PMCID: PMC1365005 DOI: 10.1111/j.1365-2125.1995.tb04450.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
1. Kenyan children with uncomplicated malaria given oral halofantrine (HF; non-micronised suspension; 8 mg base kg-1 body weight 6 hourly for three doses) showed wide variation in the disposition of HF and desbutylhalofantrine (HFm). 2. Eight Kenyan children with severe (prostrate) falciparum malaria who were receiving intravenous quinine, were given the same HF regimen by nasogastric tube. One patient had undetectable HF and two had undetectable HFm at all times after drug administration. 3. The mean AUC(0,24 h) of HF in prostrate children was half (7.54 compared with 13.10 micrograms ml-1 h) (P = 0.06), and that for HFm one-third (0.84 compared with 2.51 micrograms ml-1 h) (P < 0.05) of the value in children with uncomplicated malaria. 4. Oral HF may be appropriate for some cases of uncomplicated falciparum malaria in Africa, but in patients with severe malaria, the bioavailability of HF and HFm may be inadequate.
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Affiliation(s)
- W M Watkins
- Kenya Medical Research Institute, CRC. Kilifi Research Unit
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Humberstone AJ, Currie GJ, Porter CJ, Scanlon MJ, Charman WN. A simplified liquid chromatography assay for the quantitation of halofantrine and desbutylhalofantrine in plasma and identification of a degradation product of desbutylhalofantrine formed under alkaline conditions. J Pharm Biomed Anal 1995; 13:265-72. [PMID: 7619886 DOI: 10.1016/0731-7085(95)01256-k] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
The development of a new and simplified, validated LC assay for the quantitation of halofantrine and desbutylhalofantrine in plasma is described. The methodology employs an inexpensive, rapid and simple liquid-liquid extraction procedure in combination with previously reported chromatographic conditions. The method has been employed to study aspects of the pharmacokinetics of orally administered halofantrine in beagle dogs and some preliminary data are presented. During development of the extraction procedure, degradation of desbutylhalofantrine was observed under non-acidic conditions in the extraction solvent (tert-butyl methyl ether) and we also report the structural elucidation of the breakdown product and the conditions required to avoid this degradation.
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Affiliation(s)
- A J Humberstone
- Department of Pharmaceutics, Victorian College of Pharmacy, Monash University, Parkville, Australia
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