Pharmacokinetics and Bioequivalence Evaluation of Two Fixed-Dose Tablet Formulations of Dihydroartemisinin and Piperaquine in Vietnamese Subjects

Pharmacokinetic differences between piperaquine (PQ) base and PQ tetraphosphate were investigated in 34 Papua New Guinean children aged 5 to 10 years treated for uncomplicated malaria with artemisinin-PQ (ART-PQ) base or dihydroartemisinin-PQ (DHA-PQ) tetraphosphate. Twelve children received ART-PQ base (two daily doses of 3 mg of ART and 18 mg of PQ base as granules/kg of body weight) as recommended by the manufacturer, with regular clinical assessment and blood sampling over 56 days. PQ concentrations in plasma samples collected from 22 children of similar ages with malaria in a previously published pharmacokinetic study of DHA-PQ tetraphosphate (three daily doses of 2.5 mg of ART and 20 mg of PQ tetraphosphate as tablets/kg of body weight) were available for comparison. The disposition of ART was also assessed in the 12 children who received ART-PQ base. Plasma PQ was assayed by high-performance liquid chromatography with UV detection, and ART was assayed using liquid chromatography-mass spectrometry. Multicompartment pharmacokinetic models for PQ and ART were developed using a population-based approach. ART-PQ base was well tolerated, and initial fever abatement and parasite clearance were prompt. There were no differences between the two treatments in the values for the PQ area under the concentration-time curve from time zero to infinity (AUC 0 -ؕ ), with medians of 49,451 (n ‫؍‬ 12) and 44,556 (n ‫؍‬ 22) g · h/liter for ART-PQ base and DHA-PQ tetraphosphate, respectively. Recurrent parasitemia was associated with lower PQ exposure. Using a two-compartment ART model, the median AUC 0 -ؕ was 1,652 g · h/liter. There was evidence of autoinduction of ART metabolism (relative bioavailability for the second dose, 0.27). These and previously published data suggest that a 3-day ART-PQ base regimen should be further evaluated, in line with World Health Organization recommendations for all artemisinin combination therapies.T he most recent World Health Organization (WHO) recommendations for the treatment of uncomplicated malaria include a 3-day course of dihydroartemisinin plus piperaquine (DHA-PQ) as a first-line artemisinin (ART) combination therapy (ACT) (48). Various formulations of DHA-PQ are marketed in tropical countries (Duo-cotecxin, Combimal, and P-Alaxin; http://www.actwatch.info /resources/drugs_home03_search.asp) or are in development (Eurartesim) (20), and all employ PQ tetraphosphate as the DHA partner drug. DHA is a semisynthetic derivative of ART, and its production adds to the manufacturing cost, but, unlike ART, it does not exhibit autoinduction of metabolism. In addition, although the tetraphosphate salt of PQ has greater water solubility and therefore may have better oral bioavailability, incorporation of the lipid-soluble PQ base should also simplify production.Artequick (Artepharm Co. Ltd., Guangzhou, China) is an ACT that contains ART in place of DHA and PQ base rather than PQ tetraphosphate. This combination is formulated as tablets but also as granules for pediatric use. It is marketed in ...

Section: Discussionsupporting

confidence: 79%

Section: Discussionmentioning

confidence: 98%

Pharmacokinetic Comparison of Two Piperaquine-Containing Artemisinin Combination Therapies in Papua New Guinean Children with Uncomplicated Malaria

Salman

Page‐Sharp

Batty

et al. 2012

“…The pharmacokinetic properties of dihydroartemisinin in healthy volunteers and nonpregnant patients with malaria have been well characterized with noncompartmental analysis, but no data on the population pharmacokinetics of dihydroartemisinin when administered as the fixed dihydroartemisinin-piperaquine combination are available (7,11,19,27,40,54). Results presented in this study for nonpregnant women with malaria are in agreement with previously published results for nonpregnant patients with uncomplicated malaria.…”

Section: Figsupporting

confidence: 89%

Population Pharmacokinetics of Dihydroartemisinin and Piperaquine in Pregnant and Nonpregnant Women with Uncomplicated Malaria

Tärning

Rijken

McGready

et al. 2012

140

c Pregnant women are particularly vulnerable to malaria. The pharmacokinetic properties of antimalarial drugs are often affected by pregnancy, resulting in lower drug concentrations and a consequently higher risk of treatment failure. The objective of this study was to evaluate the population pharmacokinetic properties of piperaquine and dihydroartemisinin in pregnant and nonpregnant women with uncomplicated malaria. Twenty-four pregnant and 24 matched nonpregnant women on the Thai-Myanmar boarder were treated with a standard fixed oral 3-day treatment, and venous plasma concentrations of both drugs were measured frequently for pharmacokinetic evaluation. Population pharmacokinetics were evaluated with nonlinear mixed-effects modeling. The main pharmacokinetic finding was an unaltered total exposure to piperaquine but reduced exposure to dihydroartemisinin in pregnant compared to nonpregnant women with uncomplicated malaria. Piperaquine was best described by a three-compartment disposition model with a 45% higher elimination clearance and a 47% increase in relative bioavailability in pregnant women compared with nonpregnant women. The resulting net effect of pregnancy was an unaltered total exposure to piperaquine but a shorter terminal elimination half-life. Dihydroartemisinin was best described by a one-compartment disposition model with a 38% lower relative bioavailability in pregnant women than nonpregnant women. The resulting net effect of pregnancy was a decreased total exposure to dihydroartemisinin. The shorter terminal elimination half-life of piperaquine and lower exposure to dihydroartemisinin will shorten the posttreatment prophylactic effect and might affect cure rates. The clinical impact of these pharmacokinetic findings in pregnant women with uncomplicated malaria needs to be evaluated in larger series. Children under the age of 5 years and pregnant women are especially vulnerable to malaria. An estimated 85 million pregnancies occurred in areas with falciparum malaria transmission during 2007 (13). Malaria during pregnancy is responsible for maternal and fetal mortality (42,43). Both falciparum malaria and vivax malaria during pregnancy are associated with low birth weight resulting from intrauterine growth restriction (8, 9, 48). Effective treatment and prophylaxis of malaria in pregnancy rely on the use of efficacious antimalarial drugs.Pregnancy has substantial effects on the pharmacokinetic characteristics of many antimalarial drugs. Previous studies report artesunate, artemether, dihydroartemisinin, sulfadoxine, atovaquone, proguanil, cycloguanil, pyrimethamine, and lumefantrine concentrations to be reduced in pregnant women (25,33,34,36,44,58). This may contribute to lower antimalarial cure rates in pregnant than nonpregnant adults (58). Other studies report no pharmacokinetic differences in pregnant women compared to nonpregnant women (e.g., pyrimethamine and amodiaquine/desethylamodiaquine) or even a higher drug exposure during pregnancy (pyrimethamine) (15,25,46).Artemisinin-based combi...

“…Plasma dihydroartemisinin concentrations were measured by liquid chromatography-tandem mass spectrometry, with a lower limit of quantification of 1 ng/ml (2). The values for overall precision of analysis for dihydroartemisinin, as defined by the percent coefficient of variation of spiked samples were 6.3% at 1 ng/ml, 5.7% at 20 ng/ml, 4.6% at 200 ng/ml, and 6.6% at 750 ng/ml.…”

mentioning

confidence: 99%

“…1, and the pharmacokinetics of the two drugs are summarized in Table 1. Because dihydroartemisinin is rapidly eliminated with a t 1/2 of about 1 h in healthy Vietnamese subjects (2) and does not accumulate with daily administration, we were able to compare the pharmacokinetics of dihydroartemisinin in the Vietnamese patients after the last daily dose of the 3-day course of dihydroartemisinin-piperaquine with values obtained in healthy Vietnamese subjects given a single dose of dihydroartemisininpiperaquine (2). The mean C max and AUC of dihydroartemisinin were markedly higher in the Vietnamese malaria patients than in the healthy Vietnamese subjects (C max , 698 versus 176 ng/ml; AUC d2-ϱ , 1,949 versus 398 ng ⅐ h/ml).…”

mentioning

confidence: 99%

Pharmacokinetics and Ex Vivo Pharmacodynamic Antimalarial Activity of Dihydroartemisinin-Piperaquine in Patients with Uncomplicated Falciparum Malaria in Vietnam

Nguyen¹,

Nguyen²,

Nguyen³

et al. 2009

Self Cite

Compared to healthy subjects, malaria patients show a reduction in the mean oral clearance (1.19 versus 5.87 liters/h/kg of body weight) and apparent volume of distribution (1.47 versus 8.02 liters/kg) of dihydroartemisinin in Vietnamese patients following treatment with dihydroartemisinin-piperaquine (Artekin) for uncomplicated Plasmodium falciparum. Dihydroartemisinin is responsible for most of the ex vivo antimalarial activity of dihydroartemisinin-piperaquine.