Chloroquine Phosphate/Proguanil Hydrochloride

A method for simultaneous analysis of chloroquine, proguanil and their metabolites from a whole blood sample (80 microL) dried on a filter paper was developed. Sample preparation included a liquid extraction from the filter paper, followed by a solid-phase extraction (C18 Bond Elut cartridge). Separation was obtained by reverse-phase liquid chromatography (HPLC) using a gradient elution on an X-Terra column; UV detection was made at 254 nm. This assay was linear between 150 and 2500 ng mL(-1) for chloroquine (and metabolite) and 300 and 2500 ng mL(-1) for proguanil and cycloguanil. The lower limit of quantification was close to 50 ng mL(-1) for chloroquine (and its metabolite) and 100 ng mL(-1) for proguanil (and its metabolite). No chromatographic interference from endogenous compounds or other tested anti-malarial drugs was evidenced. Chromatographic separation takes about 40 min with a coefficient of variation below 10.3% for within- and between-batch precision. The paper sampling method was validated in 10 healthy subjects treated by Savarine. The stability of compounds and metabolites on the filter paper was evaluated at four temperatures (-20, +4, 20 and 50 degrees C) and for 1, 5 and 20 days. Cycloguanil concentrations were not influenced by storage conditions, whereas, high temperatures and prolonged storage decreased chloroquine and proguanil levels. The proposed HPLC assay is accurate, precise and cost-effective; it can be used for pharmacokinetic and epidemiological studies on anti-malarial treatments.

In France, 4,000 imported malaria cases are reported each year (7,000 to 8,000 estimated). Chemoprophylaxis is essential for prevention in travelers. When malaria is susceptible to chloroquine, this drug (Nivaquine) has to be used. It is given daily in France (1.5 mg/kg per day), from departure to four weeks after return. When low levels of chloroquino-resistance are reported, French authorities recommend the use of chloroquine + proguanil (Savarine) if the body weight is >50 kg or Nivaquine) + Paludrine), if <50 kg), or atovaquone + proguanil (Malarone). Nivaquine) (1.5 mg/kg per day) and Paludrine) (3 mg/kg per day) have to be pursued for one month after return, although Malarone) (1 pediatric tablet/10 kg per day, in children >10 kg weight) may be disrupted after one single week. Adverse events are rarer with atovaquone + proguanil, than with chloroquine + proguanil. When chloroquino-resistance is high, Malarone) or mefloquine (Lariam) are used. Weekly drug regimen is recommended with mefloquine (5 mg/kg per weight) for the travel duration and four weeks after return and the drug tolerance is good in pediatric prophylaxis. Doxycycline is used under conditions in children >8 years of age. New drugs as for tafenoquine, an amino-8 quinoleine, might enhance patients compliance if given monthly.