Self-reported data: a major tool to assess compliance with anti-malarial combination therapy among children in Senegal

Background: Although there are many methods available for measuring compliance, there is no formal gold standard. Different techniques used to measure compliance were compared among children treated by the anti-malarial amodiaquine/sulphadoxine-pyrimethamine (AQ/SP) combination therapy, in use in Senegal between 2004 and 2006. Methods: The study was carried out in 2004, in five health centres located in the Thies region (Senegal). Children who had AQ/SP prescribed for three and one day respectively at the health centre were recruited. The day following the theoretical last intake of AQ, venous blood, and urine samples were collected for anti-malarial drugs dosage. Caregivers and children above five years were interviewed concerning children's drug intake. Results: Among the children, 64.7% adhered to 80% of the prescribed dose and only 37.7% were strict full adherent to the prescription. There was 72.7% agreement between self-reported data and blood drug dosage for amodiaquine treatment. Concerning SP, results found that blood dosages were 91.4% concordant with urine tests and 90% with self-reported data based on questionnaires. Conclusion: Self-reported data could provide useful quantitative information on drug intake and administration. Under strict methodological conditions this method, easy to implement, can be used to describe patients' behaviors and their use of new anti-malarial treatment. Self-reported data is a major tool for assessing compliance in resource poor countries. Blood and urine drug dosages provide qualitative results that confirm any drug intake. Urine assays for SP could be useful to obtain public health data, for example on chemoprophylaxis among pregnant women

A high performance liquid chromatographic assay of Mefloquine in saliva after a single oral dose in healthy adult Africans

<p>Abstract</p> <p>Background</p> <p>Mefloquine-artesunate is a formulation of artemisinin based combination therapy (ACT) recommended by the World Health Organization and historically the first ACT used clinically. The use of ACT demands constant monitoring of therapeutic efficacies and drug levels, in order to ensure that optimum drug exposure is achieved and detect reduced susceptibility to these drugs. Quantification of anti-malarial drugs in biological fluids other than blood would provide a more readily applicable method of therapeutic drug monitoring in developing endemic countries. Efforts in this study were devoted to the development of a simple, field applicable, non-invasive method for assay of mefloquine in saliva.</p> <p>Methods</p> <p>A high performance liquid chromatographic method with UV detection at 220 nm for assaying mefloquine in saliva was developed and validated by comparing mefloquine concentrations in saliva and plasma samples from four healthy volunteers who received single oral dose of mefloquine. Verapamil was used as internal standard. Chromatographic separation was achieved using a Hypersil ODS column.</p> <p>Results</p> <p>Extraction recoveries of mefloquine in plasma or saliva were 76-86% or 83-93% respectively. Limit of quantification of mefloquine was 20 ng/ml. Agreement between salivary and plasma mefloquine concentrations was satisfactory (r = 0.88, <it>p </it>< 0.001). Saliva:plasma concentrations ratio was 0.42.</p> <p>Conclusion</p> <p>Disposition of mefloquine in saliva paralleled that in plasma, making salivary quantification of mefloquine potentially useful in therapeutic drug monitoring.</p

Simultaneous quantitation of the highly lipophilic atovaquone and hydrophilic strong basic proguanil and its metabolites using a new mixed-mode SPE approach and steep-gradient LC.

A bioanalytical method is described for the simultaneous quantitative analysis of the highly lipophilic atovaquone and the strong basic proguanil with metabolites in plasma. The drugs are extracted from protein precipitated plasma samples on a novel mixed-mode solid-phase extraction (SPE) column containing carboxypropyl and octyl silica as functional groups. The analytes are further separated and quantitated using a steep-gradient liquid chromatographic method on a Zorbax SB-CN column with UV detection at 245 nm. Two different internal standards (IS) are used in the method to compensate for both types of analytes. A structurally similar IS to atovaquone is added with acetonitrile to precipitate proteins from plasma. A structurally similar IS to proguanil and its metabolites is added with phosphate buffer before samples are loaded onto the SPE columns. A single elution step is sufficient to elute all analytes. The method is validated according to published guidelines and shows excellent performance. The within-day precisions, expressed as relative standard deviation, are lower than 5% for all analytes at three tested concentrations within the calibration range. The between-day precisions are lower than 13% for all analytes at the same tested concentrations. The limit of quantitation is 25 nM for the basic substances and 50 nM for atovaquone. Several considerations regarding development and optimization of a method for determination of analytes with such a difference in physiochemical properties are discussed

Simultaneous Quantitation of the Highly Lipophilic Atovaquone and Hydrophilic Strong Basic Proguanil and Its Metabolites Using a New Mixed-Mode SPE Approach and Steep-Gradient LC

A bioanalytical method is described for the simultaneous quantitative analysis of the highly lipophilic atovaquone and the strong basic proguanil with metabolites in plasma. The drugs are extracted from protein precipitated plasma samples on a novel mixed-mode solid-phase extraction (SPE) column containing carboxypropyl and octyl silica as functional groups. The analytes are further separated and quantitated using a steep-gradient liquid chromatographic method on a Zorbax SB-CN column with UV detection at 245 nm. Two different internal standards (IS) are used in the method to compensate for both types of analytes. A structurally similar IS to atovaquone is added with acetonitrile to precipitate proteins from plasma. A structurally similar IS to proguanil and its metabolites is added with phosphate buffer before samples are loaded onto the SPE columns. A single elution step is sufficient to elute all analytes. The method is validated according to published guidelines and shows excellent performance. The within-day precisions, expressed as relative standard deviation, are lower than 5% for all analytes at three tested concentrations within the calibration range. The between-day precisions are lower than 13% for all analytes at the same tested concentrations. The limit of quantitation is 25 nM for the basic substances and 50 nM for atovaquone. Several considerations regarding development and optimization of a method for determination of analytes with such a difference in physiochemical properties are discussed

Simultaneous quantitation of the highly lipophilic atovaquone and hydrophilic strong basic proguanil and its metabolites using a new mixed-mode SPE approach and steep-gradient LC.

A bioanalytical method is described for the simultaneous quantitative analysis of the highly lipophilic atovaquone and the strong basic proguanil with metabolites in plasma. The drugs are extracted from protein precipitated plasma samples on a novel mixed-mode solid-phase extraction (SPE) column containing carboxypropyl and octyl silica as functional groups. The analytes are further separated and quantitated using a steep-gradient liquid chromatographic method on a Zorbax SB-CN column with UV detection at 245 nm. Two different internal standards (IS) are used in the method to compensate for both types of analytes. A structurally similar IS to atovaquone is added with acetonitrile to precipitate proteins from plasma. A structurally similar IS to proguanil and its metabolites is added with phosphate buffer before samples are loaded onto the SPE columns. A single elution step is sufficient to elute all analytes. The method is validated according to published guidelines and shows excellent performance. The within-day precisions, expressed as relative standard deviation, are lower than 5% for all analytes at three tested concentrations within the calibration range. The between-day precisions are lower than 13% for all analytes at the same tested concentrations. The limit of quantitation is 25 nM for the basic substances and 50 nM for atovaquone. Several considerations regarding development and optimization of a method for determination of analytes with such a difference in physiochemical properties are discussed

Assay for screening for six antimalarial drugs and one metabolite using dried blood spot sampling, sequential extraction and ion-trap detection.

BACKGROUND: More parasites are becoming resistant to antimalarial drugs, and in many areas a change in first-line drug treatment is necessary. The aim of the developed assay is to help determine drug use in these areas and also to be a complement to interviewing patients, which will increase reliability of surveys. RESULTS: This assay detects quinine, mefloquine, sulfadoxine, pyrimethamine, lumefantrine, chloroquine and its metabolite desethylchloroquine in a 100-µl dried blood spot. Most of the drugs also have long half-lives that make them detectable at least 7 days after administration. The drugs are extracted from the dried blood spot with sequential extraction (due to the big differences in physicochemical properties), solid-phase extraction is used as sample clean-up and separation is performed with gradient-LC with MS ion-trap detection. CONCLUSION: Detection limits (S/N > 5:1) at 50 ng/ml or better were achieved for all drugs except lumefantrine (200 ng/ml), and thus can be used to determine patient compliance. A major advantage of using the ion-trap MS it that it will be possible to go back into the data and look for other drugs as needed

Assay for screening for six antimalarial drugs and one metabolite using dried blood spot sampling, sequential extraction and ion-trap detection.

BACKGROUND: More parasites are becoming resistant to antimalarial drugs, and in many areas a change in first-line drug treatment is necessary. The aim of the developed assay is to help determine drug use in these areas and also to be a complement to interviewing patients, which will increase reliability of surveys. RESULTS: This assay detects quinine, mefloquine, sulfadoxine, pyrimethamine, lumefantrine, chloroquine and its metabolite desethylchloroquine in a 100-µl dried blood spot. Most of the drugs also have long half-lives that make them detectable at least 7 days after administration. The drugs are extracted from the dried blood spot with sequential extraction (due to the big differences in physicochemical properties), solid-phase extraction is used as sample clean-up and separation is performed with gradient-LC with MS ion-trap detection. CONCLUSION: Detection limits (S/N &gt; 5:1) at 50 ng/ml or better were achieved for all drugs except lumefantrine (200 ng/ml), and thus can be used to determine patient compliance. A major advantage of using the ion-trap MS it that it will be possible to go back into the data and look for other drugs as needed