Gas chromatographic assay of diethylcarbamazine in human plasma for application to clinical pharmacokinetic studies

Efficacy, Safety, and Pharmacokinetics of Coadministered Diethylcarbamazine, Albendazole, and Ivermectin for Treatment of Bancroftian Filariasis

BACKGROUND

Available treatments for lymphatic filariasis (LF) are limited in their longterm clearance of microfilaria from the blood. The safety and efficacy of a single-dose triple-drug therapy of the antifilarial drugs diethylcarbamazine (DEC), ivermectin (IVM), and albendazole (ALB) for LF are unknown.

METHODS

We performed a pilot study to test the efficacy, safety, and pharmacokinetics of single-dose DEC, IVM, and ALB in Wuchereria bancrofti-infected Papua New Guineans. Adults were randomized into 2 treatment arms, DEC 6 mg/kg + ALB 400 mg (N = 12) or DEC 6 mg/kg + ALB 400 mg + IVM 200 μg/kg (N = 12), and monitored for microfilaria, parasite antigenemia, adverse events (AEs), and serum drug levels.

RESULTS

Triple-drug therapy induced >2-log reductions in microfilaria levels at 36 and 168 hours after treatment compared with approximately 1-log reduction with 2 drugs. All 12 individuals who received 3 drugs were microfilaria negative 1 year after treatment, whereas 11 of 12 individuals in the 2-drug regimen were microfilaria positive. In 6 participants followed 2 years after treatment, those who received 3 drugs remained microfilaria negative. AEs, particularly fever, myalgias, pruritus, and proteinuria/hematuria, occurred in 83% vs 50% of those receiving triple-drug compared to 2-drug treatment respectively (P = .021); all resolved within 7 days after treatment. No serious AEs were observed in either group. There was no significant effect of IVM on DEC or ALB drug levels.

CONCLUSIONS

Triple-drug therapy is safe and more effective than DEC + ALB for Bancroftian filariasis and has the potential to accelerate elimination of lymphatic filariasis.

CLINICAL TRIALS REGISTRATION

NCT01975441.

Titrimetric and spectrophotometric assay of diethylcarbamazine citrate in formulations using iodate and iodide mixture as reagents

One titrimetric and two spectrophotometric methods are proposed for the determination of diethylcarbamazine citrate (DEC) in bulk drug and in formulations using potassium iodate and potassium iodide as reagent. The methods employ the well-known analytical reaction between iodate and iodide in the presence of acid. In titrimetry (method A), the drug was treated with a measured excess of thiosulfate in the presence of unmeasured excess of iodate-iodide mixture and after a standing time of 10 min, the surplus thiosulfate was determined by back titration with iodine towards starch end point. Titrimetric assay is based on a 1:3 reaction stoichiometry between DEC and iodine and the method is applicable over 2.0-10.0 mg range. The liberated iodine is measured spectrophotometrically at 370 nm (method B) or the iodine-starch complex measured at 570 nm (method C). In both methods, the absorbance is found to be linearly dependent on the concentration of iodine, which in turn is related to DEC concentration. The calibration curves are linear over 2.5-50 and 2.5-30 µg mL-1 DEC for method B and method C, respectively. The calculated molar absorptivity and Sandell sensitivity values were 6.48×103 L mol-1 cm-1 and 0.0604 µg cm-2, respectively, for method B, and their respective values for method C are 9.96×103 L mol-1 cm-1 and 0.0393 µg cm-2. The intra-day and inter-day accuracy and precision studies were carried out according to the ICH guidelines. The methods were successfully applied to the analysis of DEC formulations.

Safety, tolerability, efficacy and plasma concentrations of diethylcarbamazine and albendazole co-administration in a field study in an area endemic for lymphatic filariasis in India

Filariasis control programmes are moving towards a strategy of repeated single-dose mass treatment of endemic populations. Using a combination, such as albendazole (ALB) to diethylcarbamazine (DEC) gives both macrofilaricidal and anti-helmintic activity. However, the safety of the combination versus DEC alone should be established in field studies in large populations prior to incorporation into national programmes. The present study compared the safety, tolerability, and efficacy of single doses of DEC 6 mg/kg + ALB placebo with DEC 6 mg/kg + ALB 400 mg in populations living in two filariasis endemic villages in the district of Wardha in western India. The study was double blind, parallel group, and randomized. Safety and tolerability study were studied in males and females older than 5 years. Safety was assessed by monitoring if adverse events (AEs) over 5 days affected daily acivities. Subjects in the 2 treatment groups experienced insignificantly different effects on daily activities and the combination was shown to be safe. Efficacy was evaluated by microfilaraemia (Mf), immunochromatographic test (ICT) and ultrasonography (USG) at 0, 3, 6, and 12 months of follow up. The efficacy study enrolled 103 male patients (aged 18-50 years) in microfilariae positive, clinical disease and asymptomatic, amicrofilaremic groups. There was no significant difference in efficacy between groups at 12 months. Within the Mf positive group, significant differences were seen in microfilaraemia (P < 0.001) with both treatments, and in USG (P < 0.001 and P < 0.004 respectively), at 12 months. The present field study has shown the combination of DEC + ALB to be as safe as the single drug DEC and thus the combination can be put in use in the national filariasis control programmes. Both drugs were adequately absorbed. The study at present does not provide evidence for the greater efficacy of the combination at 12 months follow up. While the safety of the combination has been ascertained, the incorporation or otherwise of ALB into national programmes for greater efficacy must await results of studies with longer follow up.