Chloroquine or amodiaquine combined with sulfadoxine-pyrimethamine as a treatment for uncomplicated malaria—a systematic review

Design, synthesis and evaluation of antimalarial potential of polyphosphazene linked combination therapy of primaquine and dihydroartemisinin

Various polymer drug conjugates (13-16) such as primaquine and dihydroartemisinin conjugated 2-propoxy substituted polyphosphazenes (13), primaquine and dihydroartemisinin conjugated 4-acetamidophenoxy substituted polyphosphazenes (14), primaquine and dihydroartemisinin conjugated 4-formyl substituted polyphosphazenes (15) and primaquine and dihydroartemisinin conjugated 4-aminoethylbenzoate substituted polyphosphazenes (16) were synthesized using substituted polyphosphazenes as polymer and primaquine and dihydroartemisinin as combination antimalarial pharmacophores and formulated to nanoparticles to achieve novel controlled combined drug delivery approach for radical cure of malaria. The polymeric backbone was suitably substituted to impart different physicochemical properties. The polymer-drug conjugates were characterized by IR, (1)H NMR, (31)P NMR and their molecular weights were determined by Gel Permeation Chromatography. The thermal properties of the conjugates (13-16) were studied by DSC and TGA. The conjugates (13-16) were then formulated to nanoparticles formulations to increase their uptake by hepatocytes and to achieve targeted drug delivery. The nanoparticle formulations were characterized by Zeta Sizer and their morphology were studied by TEM (Transmission Electron Microscopy) imaging. The nanoparticles formulations exhibited biphasic in vitro drug release profile, the initial burst release followed by a sustained release owing to the non-fickian diffusion during first step release and fickian diffusion during second step release. In vivo antimalarial efficacy was tested using Plasmodium berghei (NK65 resistant strain) infected swiss albino mice at different doses. The combination therapy exhibited promising antimalarial efficacy at lower doses in comparison to the standard drug combination. Further, this combination therapy provided protection over 35days without any recrudescence, thus proving to be effective against resistant malaria. The study provides an alternative combination regimen found to be effective in the treatment of resistant malaria.

Phase I randomized dose-ascending placebo-controlled trials of ferroquine--a candidate anti-malarial drug--in adults with asymptomatic Plasmodium falciparum infection

BACKGROUND

The development and spread of drug resistant Plasmodium falciparum strains is a major concern and novel anti-malarial drugs are, therefore, needed. Ferroquine is a ferrocenic derivative of chloroquine with proven anti-malarial activity against chloroquine-resistant and -sensitive P. falciparum laboratory strains.

METHODS

Adult young male aged 18 to 45 years, asymptomatic carriers of P. falciparum, were included in two-dose escalation, double-blind, randomized, placebo-controlled Phase I trials, a single dose study and a multiple dose study aiming to evaluate oral doses of ferroquine from 400 to 1,600 mg.

RESULTS

Overall, 54/66 patients (40 and 26 treated in the single and multiple dose studies, respectively) experienced at least one adverse event, 15 were under placebo. Adverse events were mainly gastrointestinal symptoms such as abdominal pain (16), diarrhoea (5), nausea (13), and vomiting (9), but also headache (11), and dizziness (5). A few patients had slightly elevated liver parameters (10/66) including two patients under placebo. Moderate changes in QTc and morphological changes in T waves were observed in the course of the study. However, no adverse cardiac effects with clinical relevance were observed.

CONCLUSIONS

These phase I trials showed that clinically, ferroquine was generally well-tolerated up to 1,600 mg as single dose and up to 800 mg as repeated dose in asymptomatic young male with P. falciparum infection. Further clinical development of ferroquine, either alone or in combination with another anti-malarial, is highly warranted and currently underway.

Investigation of amodiaquine bulk drug impurities by liquid chromatography/ion trap mass spectrometry

Three unknown impurities in an amodiaquine bulk drug sample were detected by reversed-phase high-performance liquid chromatography with ultraviolet detection (HPLC/UV). A liquid chromatography/tandem mass spectrometry (LC/MS(n)) method is described for the investigation of these impurities. Mass spectral data were acquired on an LCQ ion trap mass analyzer equipped with an electrospray ionization (ESI) source operated in positive ion mode. The fragmentation behavior of amodiaquine and its impurities has been studied. Based on the mass spectral data and the specifics of the synthetic route, the possible structures of these impurities were elucidated as 4-[(5-chloroquinolin-4-yl)amino]-2-(diethylaminomethyl)phenol (impurity I), 4-[(7-chloroquinolin-4-yl)-amino]phenol (impurity II) and 4-[(7-chloroquinolin-4-yl)amino]-2-(diethylaminomethyl)-N(1)-oxy]phenol (impurity III). The structures were confirmed by their independent synthesis and NMR spectral assignment.

Chloroquine or amodiaquine combined with sulfadoxine-pyrimethamine for treating uncomplicated malaria

BACKGROUND

Chloroquine (CQ), amodiaquine (AQ), and sulfadoxine-pyrimethamine (SP) are inexpensive drugs, but treatment failure is a problem. Combination therapy may reduce treatment failure. CQ or AQ plus SP are affordable options of combination treatment, but there is debate about their effectiveness.

OBJECTIVES

To assess the combination of CQ or AQ plus SP compared with SP alone for first-line treatment of uncomplicated falciparum malaria.

SEARCH STRATEGY

We searched the Cochrane Infectious Diseases Group Specialized Register (April 2005), CENTRAL (The Cochrane Library Issue 2, 2005), MEDLINE (1966 to April 2005), EMBASE (1974 to April 2005), LILACS (1982 to April 2005), Science Citation Index (1981 to April 2005), African Index Medicus (1993 to 1998), and reference lists. We also contacted researchers at relevant organizations and a pharmaceutical company.

SELECTION CRITERIA

Randomized controlled trials in adults or children with uncomplicated Plasmodium falciparum malaria were eligible for inclusion. The main outcomes of interest were total and clinical failure at day 28 follow up and serious adverse events.

DATA COLLECTION AND ANALYSIS

Two people independently applied the inclusion criteria. One author extracted data and another checked them independently. We used relative risk (RR) and 95% confidence intervals (CI).

MAIN RESULTS

Twelve trials (2107 participants) met the inclusion criteria. A meta-analysis of five AQ trials (461 participants) showed a statistically significant reduction in total failure at day 28 with the combination therapy (RR 0.64, 95% CI 0.46 to 0.91), and meta-analysis of three trials (384 participants) showed a significant reduction in clinical failure at day 28 (RR 0.23, 95% CI 0.11 to 0.49). The statistical significance in the total failure analysis was sensitive to losses to follow up. Data from two CQ trials showed no advantage for total failure with combination therapy at day 28. There was no evidence from the included trials of serious adverse events.

AUTHORS' CONCLUSIONS

The evidence base is not strong enough to support firm conclusions. The available evidence suggests that AQ plus SP can achieve less treatment failure than SP, but this might depend on existing levels of parasite resistance to the individual drugs.

Amodiaquine, sulfadoxine/pyrimethamine, and combination therapy for treatment of uncomplicated falciparum malaria in Kampala, Uganda: a randomised trial

BACKGROUND

Increasing Plasmodium falciparum resistance to chloroquine in sub-Saharan Africa necessitates use of alternative antimalarial agents. Affordable alternative treatments include sulfadoxine/pyrimethamine and amodiaquine. Combination of antimalarial agents can increase therapeutic efficacy and delay emergence of drug resistance. We compared the efficacy of sulfadoxine/pyrimethamine, amodiaquine, and an amodiaquine/sulfadoxine/pyrimethamine combination for treatment of uncomplicated malaria in a region of high chloroquine resistance.

METHODS

Patients with symptoms of uncomplicated falciparum malaria and confirmed disease in Kampala, Uganda, were randomly assigned to receive sulfadoxine/pyrimethamine (25 mg/kg sulfadoxine, and 1.25 mg/kg pyrimethamine) plus placebo; amodiaquine (25 mg/kg) plus placebo; or amodiaquine plus sulfadoxine/pyrimethamine. Patients were followed up for 14 days, and clinical and parasitological outcomes were assessed.

FINDINGS

90% (400/445) of patients enrolled in the study successfully completed 14 days of follow-up. Treatment failure based on clinical criteria occurred in 13 of 131 (10%) patients on sulfadoxine/ pyrimethamine, nine of 131 (7%) on amodiaquine, and four of 138 (3%) on amodiaquine/sulfadoxine/pyrimethamine. Based on parasitological criteria, treatment failed in 26%, 16%, and 10% of these patients, respectively. Amodiaquine/sulfadoxine/pyrimethamine was significantly more effective than sulfadoxine/pyrimethamine alone in children aged younger than 5 years (clinical failure in 3.5% vs 13.9%, respectively, risk difference 10.4% [95% CI, 1.6-19.3] p=0.021; parasitological failure in 12.8% vs 26.4%, risk difference 13.6% [1.2-26.0] p=0.041).

INTERPRETATION

Sulfadoxine/pyrimethamine, amodiaquine, and amodiaquine/sulfadoxine/pyrimethamine were all effective for treatment of uncomplicated falciparum malaria in Uganda. The amodiaquine/sulfadoxine/pyrimethamine combination was the most effective, and could be the optimum low-cost alternative to chloroquine in Africa.

Chloroquine or amodiaquine combined with sulfadoxine-pyrimethamine for treating uncomplicated malaria

BACKGROUND

Amodiaquine and chloroquine give fast relief from malaria symptoms, particularly fever. When used alone in areas where there is some parasite resistance they do not completely clear parasites from the blood in all cases, and so not all patients are cured of infection. The major disadvantage of using sulfadoxine-pyrimethamine alone is that it takes a relatively long time to relieve fever.

OBJECTIVES

To assess the effectiveness of chloroquine or amodiaquine given with sulfadoxine-pyrimethamine to treat uncomplicated falciparum malaria.

SEARCH STRATEGY

The Cochrane Infectious Diseases Group trials register, the Cochrane Controlled Trials Register, MEDLINE, EMBASE, Science Citation Index, African Index Medicus and LILACS were searched. Experts in the field and drug companies were contacted.

SELECTION CRITERIA

Randomised and quasi-randomised trials of chloroquine or amodiaquine given with sulfadoxine-pyrimethamine compared with either drug alone in adults or children with confirmed uncomplicated falciparum malaria.

DATA COLLECTION AND ANALYSIS

Two people independently applied the inclusion criteria. Data were extracted by the reviewer and checked independently by another person.

MAIN RESULTS

Five trials were included. Fever clearance time was reduced by combination therapy compared with sulfadoxine-pyrimethamine alone. Parasite clearance at day seven follow-up was not significantly different for chloroquine or amodiaquine treatment with or without sulfadoxine-pyrimethamine. Parasite clearance at day 28 was better with combination therapy compared with chloroquine or amodiaquine alone (odds ratio 14.28, 95% confidence interval 6.76 to 30.19), but not significantly better than sulfadoxine-pyrimethamine alone (odds ratio 3.17, 95% confidence interval 0.96 to 10.43). There was no evidence from the included trials of serious side effects with combination treatment.

REVIEWER'S CONCLUSIONS

In areas where chloroquine or amodiaquine are still effective, despite some degree of resistance, using these drugs in combination with sulfadoxine-pyrimethamine, rather than sulfadoxine-pyrimethamine alone, may make people feel better faster and improve sustained parasites clearance.