Formation and identification of a degradant in chlorproguanil–dapsone–artesunate (Dacart™) tablets

Quality and stability of artemether-lumefantrine stored under ambient conditions in rural Mali

BACKGROUND

The quality and stability of anti-malarial drugs in the Global South has long been of significant concern. Drug quality can be affected by poor or fraudulent manufacturing processes, while drug stability is affected by temperature and humidity. Knowledge of drug quality and stability is often the unique contribution of pharmacists volunteering on short-term medical mission trips.

OBJECTIVE

To determine the quality and stability of artemether-lumefantrine 20/120 mg under ambient storage conditions in rural Mali.

METHODS

One unopened blister pack of artemether-lumefantrine 20/120 mg (IPCA Laboratories, Mumbai) was stored under ambient conditions in a warehouse in a Malian village for one year. A second pack from the same lot number was stored under temperature and humidity controlled conditions in a university laboratory. The active ingredients of tablets from both packages were analysed using thin layer chromatography, nuclear magnetic resonance and infrared spectroscopy. The IPCA samples were referenced for drug identity and content to an identical American made product (Coartem(®), Novartis Pharmaceuticals).

RESULTS

Thin layer chromatographs, nuclear magnetic resonance and infrared spectroscopy results were identical for both IPCA samples and the reference product.

CONCLUSIONS

The IPCA products contained the same drugs in the same amount as on their package label and were identical to the reference product. It is concluded that they were of good quality. Spectroscopy results demonstrate the sample stored in Mali was stable for one year. Pharmacists volunteering on medical mission trips may dispense this product with confidence. At the end of a mission trip, pharmacists may store left over artemether-lumefantrine under ambient conditions for up to one year without concern for significant degradation of the active ingredients.

Glucose-6-phosphate dehydrogenase deficiency, chlorproguanil-dapsone with artesunate and post-treatment haemolysis in African children treated for uncomplicated malaria

BACKGROUND

Malaria is a leading cause of mortality, particularly in sub-Saharan African children. Prompt and efficacious treatment is important as patients may progress within a few hours to severe and possibly fatal disease. Chlorproguanil-dapsone-artesunate (CDA) was a promising artemisinin-based combination therapy (ACT), but its development was prematurely stopped because of safety concerns secondary to its associated risk of haemolytic anaemia in glucose-6-phosphate dehydrogenase (G6PD)-deficient individuals. The objective of the study was to assess whether CDA treatment and G6PD deficiency are risk factors for a post-treatment haemoglobin drop in African children<5 years of age with uncomplicated malaria.

METHODS

This case-control study was performed in the context of a larger multicentre randomized clinical trial comparing safety and efficacy of four different ACT in children with uncomplicated malaria. Children, who after treatment experienced a haemoglobin drop≥2 g/dl (cases) within the first four days (days 0, 1, 2, and 3), were compared with those without an Hb drop (controls). Cases and controls were matched for study site, sex, age and baseline haemoglobin measurements. Data were analysed using a conditional logistic regression model.

RESULTS

G6PD deficiency prevalence, homo- or hemizygous, was 8.5% (10/117) in cases and 6.8% (16/234) in controls (p=0.56). The risk of a Hb drop≥2 g/dl was not associated with either G6PD deficiency (adjusted odds ratio (AOR): 0.81; p=0.76) or CDA treatment (AOR: 1.28; p=0.37) alone. However, patients having both risk factors tended to have higher odds (AOR: 11.13; p=0.25) of experiencing a Hb drop≥2 g/dl within the first four days after treatment, however this finding was not statistically significant, mainly because G6PD deficient patients treated with CDA were very few. In non-G6PD deficient individuals, the proportion of cases was similar between treatment groups while in G6PD-deficient individuals, haemolytic anaemia occurred more frequently in children treated with CDA (56%) than in those treated with other ACT (29%), though the difference was not significant (p=0.49).

CONCLUSION

The use of CDA for treating uncomplicated malaria may increase the risk of haemolytic anaemia in G6PD-deficient children.

Capillary electrophoresis for the assay of fixed-dose combination tablets of artesunate and amodiaquine

Background

Quality control of drugs in formulations is still a major challenge in developing countries. For the quality control of artesunate and amodiaquine tablets in fixed-dose combination, only liquid chromatographic methods have been proposed in the literature. There are no capillary electrophoretic methods reported for the determination of these active substances, although this technique presents several advantages over liquid chromatography (long lifetime, low price of the capillary, low volumes of electrolyte consumption) in addition to simplicity. In this paper, a reliable capillary electrophoresis method has been developed and validated for the quality control of these drugs in commercial fixed-dose combination tablets.

Methods

Artesunate and amodiaquine hydrochloride in bilayer tablets were determined by micellar electrokinetic capillary chromatography (MEKC). Analytes were extracted from tablets by sonication with a solvent mixture phosphate buffer pH 7.0-acetonitrile containing benzoic acid as internal standard. Separation was carried out on Beckman capillary electrophoresis system equipped with fused silica capillary, 30 cm long (20 cm to detector) × 50 μm internal diameter, using a 25 mM borate buffer pH 9.2 containing 30 mM sodium dodecyl sulfate as background electrolyte, a 500 V cm⁻¹ electric field and a detection wavelength of 214 nm.

Results

Artesunate, amodiaquine and benzoic acid were separated in 6 min. The method was found to be reliable with respect to specificity,linearity of the calibration line (r² > 0.995), recovery from synthetic tablets (in the range 98–102%), repeatability (RSD 2–3%, n = 7 analytical procedures). Application to four batches of commercial formulations with different dosages gave content in good agreement with the declared content.

Conclusion

The MEKC method proposed is reliable for the determination of artesunate and amodiaquine hydrochloride in fixed-dose combination tablets. The method is well-suited for drug quality control and detection of counterfeit or substandard medicines.