Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0024530 (malaria)
 44,886 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The pharmacokinetics of quinine was investigated in patients with acute falciparum malaria treated with quinine alone or in the presence of doxycycline. Twenty-six patients divided into two groups of equal number were enrolled in the study. In the absence of doxycycline, the volume of distribution of quinine (mean +/- SD) was estimated to be 1.32 +/- 0.32 L/kg, and its clearance was 0.125 +/- 0.47 L/h/kg, which was only in partial agreement with previously published data. No effect of doxycycline on the pharmacokinetics of quinine was observed.
Ther Drug Monit 1991 Nov
PMID:Pharmacokinetics of quinine and doxycycline in patients with acute falciparum malaria: a study in Africa. 177 46

A simple, rapid, and accurate high-performance liquid chromatographic method using fluorescence detection is described for the measurement of ciprofloxacin in plasma, whole blood, and erythrocytes. Ciprofloxacin and the internal standard difloxacin were separated on a mu-Bondapak C18 column (30 cm x 3.9 mm inside diameter, 10 microns particle size), using a mobile phase of 0.1 M phosphate buffer (pH 2.5):acetonitrile (75:25, vol/vol). The retention times were 5.1 min for ciprofloxacin and 7.9 min for difloxacin. The compounds were extracted from the three biological fluids using protein precipitation followed by a single-step liquid-liquid extraction. The assay is precise, with interassay coefficients of variation of less than or equal to 9.1% and an accuracy of less than or equal to 7.4% at 0.5 and 5.0 micrograms/ml (n = 5). The mean extraction recoveries of ciprofloxacin in plasma, whole blood, and erythrocytes were 84.4, 63.9, and 48.0%. The limit of detection for ciprofloxacin is 25 ng/ml. Ciprofloxacin concentrations in the three biological fluids were measured in patients with uncomplicated falciparum malaria to demonstrate the application of the method.
Ther Drug Monit 1991 May
PMID:Measurement of ciprofloxacin in human plasma, whole blood, and erythrocytes by high-performance liquid chromatography. 192 83

A reversed-phase high performance liquid chromatography method was developed to simultaneously estimate serum concentrations of dapsone (DDS), monoacetyldapsone (MADDS), and pyrimethamine (PYR) in 34 young adult Chinese men after they had taken the sixth weekly dose of Maloprim for malaria prophylaxis. Serum concentrations of DDS, MADDS, and PYR after 24 h were (mean +/- SEM) 374 +/- 31.3, 310 +/- 30.4, and 121 +/- 7.9 ng/ml, respectively. The 72-h serum concentrations of DDS, MADDS, and PYR were (mean +/- SEM) 134 +/- 21.6, 115 +/- 17.9, and 80 +/- 7.2 ng/ml, respectively. Serum concentrations of DDS and MADDS in many subjects after 120 h were less than 20 ng/ml, while mean +/- SEM concentration of PYR was 53 +/- 5.6 ng/ml. Acetylator phenotyping of the subjects showed that there were 31 (91%) fast acetylators, three (9%) intermediate acetylators, and no slow acetylators.
Ther Drug Monit 1985
PMID:Simultaneous estimation of serum concentrations of dapsone, monoacetyldapsone, and pyrimethamine in Chinese men on maloprim for malaria prophylaxis using reversed-phase high performance liquid chromatography. 390 34

A high-performance liquid chromatography (HPLC) method was developed for the simultaneous analysis of trimethoprim (TMP), sulphamethoxazole (SMX), and acetylsulphamethoxazole (AcSMX) in small amounts of blood. The method involved precipitation with 50 microL trichloracetic acid (1M) to 125 microL plasma or serum sample. 60 microL supernatant was added to 60 microL mobile phase, modified with 50microL 1 M sodium hydroxide/mL. The mobile phase consisted of 20% acetonitrile and 80% phosphate buffer adjusted to pH 6.15. Using 125 microL of the sample, limits of quantitation were 0.1 microg/mL for TMP, 1.0 microg/mL for SMX, and 1.0 microg/mL for AcSMX. The precision of the method was 2% to 11% over the range of concentrations tested, 0.5-30 microg/mL for TMP, 5-300 microg/mL for SMX, and 2.5-150 microg/mL for AcSMX, respectively. No interference with other commonly used drugs was observed. The method is rapid, simple, specific, and sensitive enough for pharmacokinetic studies. The small amount of blood required makes it suitable for pediatric patients. The method was used to analyze samples from Tanzanian children aged 6-59 months participating in a cotrimoxazole (TMP/SMX)/chloroquine randomized trial for the treatment of uncomplicated malaria. Venous blood samples from 68 children were collected 2 hours after the first dose of TMP/SMX (4 mg/kg TMP/20 mg/kg SMX at two divided doses for 5 days) and again at treatment day 4. Individual variations in plasma concentrations of TMP, SMX, and AcSMX were considerable. The mean and SEM plasma concentrations (g/mL) of TMP, SMX, and AcSMX 2 hours after the first treatment dose were 2.0 +/- 1.0 (range 0.5-6), 53 +/- 22 (range 24-146), and 13.5 +/- 12 (range 0-65), respectively. On the fourth day the attained plasma concentrations were not significantly different from samples collected after the first dose.
Ther Drug Monit 1999 Dec
PMID:A reversed-phase high-performance liquid chromatography method for the determination of cotrimoxazole (trimethoprim/ sulphamethoxazole) in children treated for malaria. 1060 20

Quinine is an optical isomer of quinidine. Both quinine and chloroquine (an aminoquinoline derivative) are used in treating malaria. The authors studied cross-reactivity of quinine and chloroquine with the quinidine immunoassays using the TDx and AxSYM analyzers (Abbott Laboratories, Abbott Park, IL). The authors observed no cross-reactivity of chloroquine with quinidine immunoassays (TDx and AXSYM) even when drug-free serum was supplemented with 1000 microg/mL chloriquine. The authors observed no cross-reactivity of quinine up to a concentration of 250 microg/mL. At higher concentrations, the authors observed a small cross-reactivity. The cross-reactivity of a substance should be studied in the presence of the primary analyte. When serum pools prepared from patients receiving quinidine were supplemented with various concentrations of quinine or chloroquine, the authors observed statistically significant declines in quinidine concentrations with higher concentrations of both quinine and chloroquine. The authors observed significant cross-reactivity of L-amphetamine with the amphetamine immunoassay also marketed by Abbott Laboratories and run on the AxSYM analyzer. The authors conclude that although the antibody used in the quinidine assay is stereospecific, the antibody used in the amphetamine assay by the same manufacturer is not stereospecific.
Ther Drug Monit 2000 Apr
PMID:Stereospecificity of antibody: quinine, the optical isomer of quinidine and anti-malarial drug chloroquine do not cross-react with quinidine immunoassays. 1077 29

A simple, rapid, and accurate high-pressure liquid chromatographic method with fluorescence detection is described for the measurement of tafenoquine (TQ) (also known as WR 238605) from human plasma and venous and capillary blood. Tafenoquine was measured in plasma and venous blood following protein precipitation. Chromatographic separation was achieved using a Waters S5P Spherisorb phenyl analytical cartridge (150 mm x 4.6 mm I.D., 5 microm particle size) (Waters, Milford, MA, USA) and a mobile phase of 22 mM ammonium acetate, pH 4:acetonitrile (45:55, vol/vol). The flow rate was 1.5 mL/min and the retention times were approximately 3.5 min for WR VIIIAc (internal standard) and approximately 7.8 min for TQ. The interday and intraday coefficients of variation of TQ over a concentration range of 20-1000 ng/mL in plasma were < or =8.4% and in venous blood were < or =9.6%. The mean percent difference between added concentration and obtained concentration was 7.3% in plasma and 8.5% in venous blood over the corresponding concentration range. The limit of quantitation for both fluids was 10 ng/mL. Tafenoquine concentrations were comparable between capillary and venous blood with no significant difference between measurement in both biological fluids. The clinical application of the method was demonstrated by measuring plasma and whole blood concentrations of TQ from participants in a chemosuppression trial of the drug against malaria infections in Thailand.
Ther Drug Monit 2000 Apr
PMID:Measurement of tafenoquine (WR 238605) in human plasma and venous and capillary blood by high-pressure liquid chromatography. 1077 31

The study group comprised 118 patients suspected of malaria who underwent an examination following their return to Poland from the tropical countries. Evaluation of the admitted patients was based on epidemiological, clinical and parasitological criteria. The obtained data allowed to confirm acute malaria in 20 patients (16.9%) and malaria in the past, in 32 patients (27.1%). In the remaining 65 patients (55.1%) we excluded malaria. Malaria caused by P. vivax was confirmed in 5 patients, by P. falciparum in 9 patients. A mixed invasion was diagnosed in 6 patients including: P. falciparum and P. vivax in 3 cases; P. vivax, P. ovale and P. malariae in 2 cases; P. falciparum, P. vivax and P. ovale in 1 patient. We noted no relationship between the severity of the clinical course and IFA results. It was found an atypical clinical course of malaria and diagnostic difficulties in patients who used chemosuppression for malaria prophylaxis.
Med Sci Monit
PMID:Clinical and parasitological appraisal of patients with imported malaria. 1120 37

Quinine sulfate has been the drug of choice for the treatment of the ever-increasing number of cases of falciparum malaria in tropical countries. Because of the spectrum of adverse effects produced by the drug in the so-called cinchona syndrome, the variation in its pharmacokinetics during the episodes of falciparum malaria, and the different therapeutic regimens proposed in different countries, the authors monitored quinine plasma concentrations in daily samples of 20 men of the Amazon region in Brazil with nonsevere falciparum malaria who were administered 1 g quinine sulfate every 12 hours for 7 days. Three blood samples were collected from each patient each day: two immediately before administration of the drug (7 am and 7 pm) and one at 11 am. A total of 440 samples were analyzed by a validated method developed in the authors' laboratories using the high-performance liquid chromatographic technique. The overall quinine plasma levels obtained varied from 1.52 to 16.89 microg/mL. From the second day of treatment, overall levels varied from 2.33 to 14.29 microg/mL; the peak concentrations showed values from 4.22 to 16.89 microg/mL, showing the efficacy of the therapeutic regimen used. Adverse effects (signs and symptoms of cinchonism) were observed in all patients. However, no cases of hypoglycemia were detected. Intrapatient comparisons of the obtained quinine plasma concentrations were statistically significant. The quinine dose may be reduced on day 4 of treatment when asexual parasitemia is absent. This way, no resistance to the drug is observed, cinchonism can be minimized, and good adherence to the regimen is obtained.
Ther Drug Monit 2001 Dec
PMID:Drug monitoring of quinine in men with nonsevere falciparum malaria: study in the Amazon region of Brazil. 1180 92

This paper's focus is prevention of sickle cell adhesion resulting from the erythrocyte's prematurely denatured hemoglobin. This denatured hemoglobin causes a molecule called band 3 to cluster on the erythrocyte's surface and adhere to the CD36 molecule located on the microvascular endothelium. Natural antibodies recognize these clusters on senescent erythrocytes and prevent their endothelial adhesion and target them for reticuloendothelial elimination. Band 3 is also displayed on the erythrocytes of individuals with falciparum malaria and the vaso-occlusive pathology in these patients is prevented in individuals with sickle trait. The hypothesis is that prematurely denatured sickle hemoglobin results in an up regulation of natural antibodies which control erythrocyte adhesion in both malaria and sickle cell disease.
Med Sci Monit 2002 May
PMID:Modulation of sickle cell crisis by naturally occurring band 3 specific antibodies -- a malaria link. 1201 59

The prevalence of multidrug-resistant malaria parasites brings about the switch from an antimalarial drug with poor therapeutic outcome to an effective alternative, resulting in overlap in the plasma drug levels. In this study, the influence of prior administration of amodiaquine on the pharmacokinetics and electrocardiographic effect of halofantrine (HF) was investigated in healthy volunteers. Ten healthy male subjects were each given single oral doses of 500 mg HF alone or with 600 mg of amodiaquine hydrochloride (AQ) administered 24 hours before the HF dose in a crossover fashion. Blood samples, collected at predetermined time intervals, were analyzed for HF and its major metabolite, desbutylhalofantrine (HFM) using a validated high-performance liquid chromatography method. Electrocardiogram for each volunteer was taken at predetermined time points. Results showed that prior administration of amodiaquine resulted in no significant changes (P > 0.05) in any of the pharmacokinetic parameters of HF. For example, the parameter values for HF alone and with AQ were: Cmax 144 +/- 53 versus 164 +/- 58 microg/L; T1/2beta 142 +/- 23 versus 139 +/- 28 hours; Cl/F 37.3 +/- 13.9 versus 32.3 +/- 11.4 L/h; and metabolic ratio 1.2 +/- 0.5 vs 1.1 +/- 0.6 Similarly, the disposition of HFM was not significantly altered (P > 0.05) after an earlier exposure to amodiaquine. In addition, the presence of AQ was linked with a further lengthening of the QT interval compared with the effect of HF alone. This study suggests that prior administration of AQ does not result in a significant alteration of the pharmacokinetics of HF but may be associated with an increased risk of QT prolongation. It may be necessary to exercise caution in the use of HF for malaria treatment in persons who have recently received AQ.
Ther Drug Monit 2007 Apr
PMID:Effects of prior administration of amodiaquine on the disposition of halofantrine in healthy volunteers. 1741 75


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