A Phase 3, Double-Blind, Randomized Study of Arterolane Maleate-Piperaquine Phosphate vs Artemether-Lumefantrine for Falciparum Malaria in Adolescent and Adult Patients in Asia and Africa.

BACKGROUND: Artemisinins, which are derived from plants, are subject to risk of supply interruption due to climatic changes. Consequently, an effort to identify a new synthetic antimalarial was initiated. A fixed-dose combination of arterolane maleate (AM), a new synthetic trioxolane, with piperaquine phosphate (PQP), a long half-life bisquinoline, was evaluated in patients with uncomplicatedPlasmodium falciparummalaria. METHODS: In this multicenter, randomized, double-blind, comparative, parallel-group trial, 1072 patients aged 12-65 years withP. falciparummonoinfection received either AM-PQP (714 patients) once daily or artemether-lumefantrine (A-L; 358 patients) twice daily for 3 days. All patients were followed up until day 42. RESULTS: Of the 714 patients in the AM-PQP group, 638 (89.4%) completed the study; of the 358 patients in the A-L group, 301(84.1%) completed the study. In both groups, the polymerase chain reaction corrected adequate clinical and parasitological response (PCR-corrected ACPR) on day 28 in intent-to-treat (ITT) and per-protocol (PP) populations was 92.86% and 92.46% and 99.25% and 99.07%, respectively. The corresponding figures on day 42 in the ITT and PP populations were 90.48% and 91.34%, respectively. After adjusting for survival ITT, the PCR-corrected ACPR on day 42 was >98% in both groups. The overall incidence of adverse events was comparable. CONCLUSIONS: AM-PQP showed comparable efficacy and safety to A-L in the treatment of uncomplicatedP. falciparummalaria in adolescent and adult patients. AM-PQP demonstrated high clinical and parasitological response rates as well as rapid parasite clearance. CLINICAL TRIALS REGISTRATION: India. CTRI/2009/091/000101.

Comparison of the safety and efficacy of fixed-dose combination of arterolane maleate and piperaquine phosphate with chloroquine in acute, uncomplicated Plasmodium vivax malaria: a phase III, multicentric, open-label study.

BACKGROUND: Chloroquine has been the treatment of choice for acute vivax malaria for more than 60 years. Malaria caused by Plasmodium vivax has recently shown resistance to chloroquine in some places. This study compared the efficacy and safety of fixed dose combination (FDC) of arterolane maleate and piperaquine phosphate (PQP) with chloroquine in the treatment of uncomplicated vivax malaria. METHODS: Patients aged 13-65 years with confirmed mono-infection of P. vivax along with fever or fever in the previous 48 h were included. The 317 eligible patients were randomly assigned to receive FDC of arterolane maleate and PQP (n = 159) or chloroquine (n = 158) for 3 days. Primaquine was given as an anti-relapse measure on day 3 and continued for 14 consecutive days. Primary efficacy analysis included assessment of the proportion of aparasitaemic and afebrile patients at 72 h. Safety endpoints were analysis of adverse events, vital signs, laboratory data, and abnormalities on electrocardiograph. Patients participated in the study for at least 42 days. RESULTS: In per protocol population, the proportion of aparasitaemic and afebrile patients at 72 h was 100% (140/140) in the FDC of arterolane maleate and PQP group, and 99.3% (145/146) in the chloroquine group (Fisher, p > 0.9999). In intent to treat population, the corresponding value was reported to be 96.9% (154/159) in the FDC of arterolane maleate and PQP group and 98.7 % (156/158) in the chloroquine group (Fisher, p = 0.4479). The median parasite clearance time was 24 h in FDC of arterolane maleate and PQP group and 26 h in chloroquine group (Log-rank, p = 0.2264). Similarly, median fever clearance time was 24 h in both the groups (Log-rank, p = 0.7750). In PP population, day 28 cure rates were 100 % in both the groups (95% CI (96.52, 100.0 for FDC of arterolane maleate and PQP and 96.73, 100.0 in chloroquine group)). Incidence of adverse events was 82.4% in the FDC of arterolane maleate and PQP group and 85.4% in the chloroquine group. Most of the adverse events were mild to moderate in intensity. The commonly reported clinical adverse events in the FDC of arterolane maleate and PQP versus chloroquine group were vomiting (5.0 vs 5.1%), headache (1.3 vs 3.2%) and prolonged QT (1.9 vs 3.2%). No deaths were reported. The pharmacokinetic analysis indicates that arterolane maleate is well absorbed and has a relatively short t1/2 of 3.2 h. Piperaquine is also well absorbed after oral administration with a t1/2 of about 228.33 h. CONCLUSIONS: The study showed that FDC of arterolane maleate and PQP effectively cured vivax malaria and attained acceptable level of cure up to day 28. Both the groups showed similar safety profile. Trial Registration Clinical Trial Registry India: CTRI/2011/11/002129.

Efficacy and safety of fixed dose combination of arterolane maleate and piperaquine phosphate dispersible tablets in paediatric patients with acute uncomplicated Plasmodium falciparum malaria: a phase II, multicentric, open-label study.

BACKGROUND: The World Health Organization (WHO) recommends artemisinin combination therapy (ACT) for the treatment of uncomplicated Plasmodium falciparum malaria. The present study investigated the efficacy and safety of fixed dose combination (FDC) of arterolane maleate 37.5 mg and piperaquine phosphate (PQP) 187.5 mg dispersible tablets in paediatric patients aged 6 months to 12 years. METHODS: Male and female patients aged 6 months to 12 years who were confirmed cases of P. falciparum mono-infection with fever or documented history of fever in the previous 24 h were included. The patients were administered FDC of arterolane maleate and PQP as single daily doses for three consecutive days based on their age. The primary efficacy outcome was proportion of patients with polymerase chain reaction (PCR)-corrected adequate clinical and parasitological response (ACPR) on day 28. Safety was analysed based on adverse events (AE), laboratory abnormalities and abnormalities on electrocardiograph. RESULTS: A total of 141 eligible paediatric patients received FDC of arterolane maleate and PQP in a 42-day follow-up study. All the enrolled patients (141) were included in intention to treat (ITT) and safety analyses, and 126 patients were considered in per protocol (PP) population. The PCR-corrected ACPR on day 28 was achieved in all patients (100 %; 95 % CI 97.11-100) included in PP population. The median parasite clearance time (PCT) and fever clearance time (FCT) were 24 h (95 % CI 18.0-24.0) and 10 h (95 % CI 4.0-18.0), respectively. The most frequently reported clinical AE was vomiting. Majority of the AEs were mild to moderate in severity and resolved without sequelae. No patient was discontinued for any QTc (corrected QT interval) prolongation. No deaths or serious AEs were reported during the study. CONCLUSION: The findings from this study showed that FDC of arterolane maleate and PQP effectively cures P. falciparum malaria and attains acceptable level of cure by day 28 in paediatric patients. The efficacy and safety results observed in children warrants further studies on FDC of arterolane maleate and PQP dispersible tablets. TRIAL REGISTRATION: Clinical Trial Registry India: CTRI/2009/091/000531.

Safety, tolerability and pharmacokinetic profile of single and multiple oral doses of arterolane (RBx11160) maleate in healthy subjects.

Arterolane (RBx11160, OZ277) maleate is a rapidly acting synthetic trioxolane anti-malarial. This randomized, placebo controlled study was a phase I study to evaluate the clinical safety and tolerability as well as pharmacokinetics (PKs) of arterolane maleate including food effect. Eight single rising oral doses of arterolane (25, 50, 100, 150, 200, 300, 400, 600 mg), food effect under fed and fasting conditions at 100 mg dose and four multiple oral dose regimens (25, 50, 100, 200 mg) were administered once daily for 7 days in 64 healthy young males (Caucasian). A randomized, placebo-controlled study was also conducted in healthy elderly males and females (Caucasian) to investigate PKs, safety and tolerability of single oral dose (100 mg) of arterolane. All doses were well tolerated after oral administration. The initial peak of arterolane was apparent at 2-3 hours post-dose followed by a secondary peak at approximately 5 hours post-dose. Thereafter, plasma arterolane concentration declined with a geometric mean t1/2 of approximately 2-4 hours. The PKs of arterolane appeared to be time-invariant after repeated once-daily dosing. The incidence of adverse events was similar for placebo and active treatments. Arterolane had similar PKs and tolerability in elderly and younger subjects and between elderly males and females.

Evaluation of the effect of ammonia on nicotine pharmacokinetics using rapid arterial sampling.

INTRODUCTION: The nicotine bolus theory states that the dependence-producing potential of cigarettes relates to a rapid increase in nicotine at brain receptor sites. It has been suggested that ammonia, a compound typically found in tobacco products, further increases the amount of nicotine absorbed and its absorption rate. The aim of this study was to determine whether different ammonia yields in cigarettes affected the rate or amount of nicotine absorption from the lungs to arterial circulation. METHODS: 34 adult smokers received 3 separate puffs from each of 2 test cigarettes with different ammonia yields (ammonia in smoke: 10.1 µg per cigarette vs. 18.9 µg per cigarette), followed by rapid radial arterial blood sampling (maximum one sample per second) with 30 min between puffs. Arterial blood samples were assayed for nicotine by liquid chromatography tandem mass spectrometry. Pharmacokinetic modeling was performed and the two test cigarettes were assessed for bioequivalence. RESULTS: No significant differences were found in area under the curve, C(max), or T((max)) and the 2 test cigarettes were found to be bioequivalent based on 2 one-sided tests at a significance level of 5%. In addition, the zero-order rate constant (k(0)) obtained from the initial slope of the curves and the model-dependent first-order rate constant (k(a)) were not significantly different. CONCLUSIONS: This study provides strong evidence that the different ammonia yields of the test cigarettes had no impact on nicotine pharmacokinetics; thus, the ammonia did not increase the rate or amount of nicotine absorption from a puff of cigarette smoke.

Rapid automated blood sampling system for pharmacokinetics studies of cigarette smoking.

INTRODUCTION: We developed an automated sampling system to allow multiple, discrete blood samples from a human participant to be collected rapidly and immediately following cigarette smoke exposure. We reported the details of the sampling system along with the results of a pilot study for evaluation of the system. METHODS: Components of the system include silastic tubing, solenoid pinch valves, a peristaltic pump, and a fraction collector. This system incorporates a smoking machine that allows precise delivery of cigarette smoke through a mouthpiece and intricate timing to correlate blood samples with smoke inhalation. All components are controlled via integration from a user interface and are fully customizable. We performed several tests to evaluate the equipment, including tubing dead volume, leakage tests, and sample reproducibility. We also performed a pilot study with 6 adult smokers, who received 6 controlled puffs of a research test cigarette. Each inhalation was followed by radial arterial blood collection (1 sample per second tapered to 1 sample every 4 s) for 1 min. Samples were evaluated for nicotine via liquid chromatography-tandem mass spectrometric methods. RESULTS: Sampling times and volumes were sufficient for nicotine analysis. No adverse effects were seen in the pilot study, and a 30-min washout period was deemed appropriate between puffs. A significant rise in plasma nicotine levels above baseline after inhalation of smoke was consistently detected in all participants. DISCUSSION: The unique advantage of this system is to allow rapid blood sampling after a puff of cigarette smoke, with the benefits of reproducibility, reduction in labor intensity, and high temporal resolution.

A LC-electrospray tandem MS method for the analysis of naltrexone in canine plasma employing a molecular model to demonstrate the absence of internal standard deuterium isotope effects.

A simple and sensitive method is described for the determination of naltrexone (NAL), an opioid antagonist, in dog plasma. Sample processing involved a single step liquid-liquid extraction, followed by evaporation of the supernatant, and reconstitution of the residue prior to injection into the liquid chromatograph. The peak height ratio of NAL to [15,15,16-(2)H] naltrexone (NAL-d(3)) was used for quantitation. Observation of the chromatograms for NAL and NAL-d(3) revealed that the mean retention times of the compounds were 1.32 and 1.31 min, respectively. The almost identical retention times possibly accounted for the absence of matrix effects influencing quantitation. Molecular mechanics calculations using SYBYL software were carried out to qualitatively and quantitatively assess analyte and isotopic internal standard stationary phase interactions. Binding energy values of -10.22 and -10.26 kcal/mole were obtained for NAL and NAL-d(3), respectively. These data predict, semi-quantitatively, the absence of deuterium isotope effects that may influence quantitation. Calibration curves were linear from 10 pg/mL to 5014 pg/mL with a weighting factor of 1/x. Precision and accuracy and reverse predicted concentration residuals were within 15%. The method has been used successfully for the analysis of plasma samples from a pilot subcutaneous implantation study in dog.

A 'biorelevant' approach to accelerated in vitro drug release testing of a biodegradable, naltrexone implant.

The development of a 'biorelevant' approach for accelerating drug release from an implant is described. A miniature, capillary system has been shown previously to be suitable for real-time release tests for a biodegradable, naltrexone implant. Whereas the real-time study under physiological condition was essential for evaluation of the system, the accelerated (short-term) method provides for a faster assessment of in vitro drug release that would be useful in product development and quality control. Increased temperature was employed as the mechanism for accelerating drug release. Release rates were investigated and compared using modifications of two devices: the flow-through cell and the new, potentially more 'biorelevant' capillary device. The data generated for accelerated release using both devices through 45 days indicated approximately two-fold and four-fold increases in release rates at 45 and 55 degrees C, respectively, as compared to the real-time release rate. The similar activation energy values for both devices obtained from Arrhenius plots demonstrated that the release mechanism had been consistent; and that the rates of release could be used for long-term prediction. The rate of release reverted to that observed in real-time data, however, upon a reduction of temperature to 38 degrees C. The results demonstrated that temperature was the sole factor involved in modification of the release rate in vitro. The profiles using both systems followed zero-order kinetics after an initial period of burst release.

A 'biorelevant' system to investigate in vitro drug released from a naltrexone implant.

This research is based on the recognized need for an in vitro release method for drug implants that better simulate physiological conditions at the site of implantation ('biorelevance'). In this paper, we describe the evaluation of a 'biorelevant' approach for in vitro drug release testing of a biodegradable implant of naltrexone in a pre-clinical stage of development. A miniature, capillary cell culture device was modified and tested as a biorelevant alternative for a standard commercially available flow-through cell. The real-time data generated through 90 days indicated a 48% lower rate of release for the capillary system. The profiles using both systems followed zero-order kinetics after an initial period of burst release. In vitro release data from the capillary device resulted in a 1-to-1 correlation with dog plasma pharmacokinetic data, and furthermore, the capillary device potentially simulated the lag-time in absorption more effectively than the flow-through cell. Scanning electron micrographs revealed that the sheath was continuous with no signs of cracks at the end of in vitro and in vivo studies. However, at the interface of the sheath and the core, intercalating, "finger-like" projections were observed consistent with penetration of the medium. No macroscopic or clinical toxicity signs were observed during the in vivo implantation study.

Characterization of a potential medium for 'biorelevant' in vitro release testing of a naltrexone implant, employing a validated stability-indicating HPLC method.

A variety of factors have been recognized that influence media optimization for drug release studies of implant dosage forms. Of primary importance is selection of a medium that physiologically mimics the milieu at the site of administration (a condition termed 'biorelevance'). We describe in this paper, the characterization of Hanks' balanced salts solution, with necessary modification, for application as a 'biorelevant' medium for in vitro release studies of a biodegradable, subcutaneous implant of naltrexone. A detailed investigation of changes in pH, osmolality and ultraviolet (UV) spectrum as a function of time and temperature was conducted. Variation in the parameters evaluated was found to be within acceptable limits. Validation of a simple and selective, high performance liquid chromatography (HPLC) assay method for naltrexone was carried out to evaluate stability. The calibration curves were linear from 0.16 to 20.00 microg ml(-1). Imprecision and inaccuracy were less than 2% and no interference was observed from degradation peaks. Stability studies of naltrexone indicated the media should be replaced every 7-8 days for real-time testing. This was applied to an investigation of in vitro drug release. The method has been proven to be suitable for investigation of naltrexone released from the implant.

Profiling in vitro drug release from subcutaneous implants: a review of current status and potential implications on drug product development.

This review presents current methods and strategies for studying the release characteristics of drugs from subcutaneous implant dosage forms. Implants are dosage forms that are subcutaneously placed with the aid of surgery or a hypodermic needle, and are designed to release drugs over a prolonged period of time. In most cases, the objective of a release test is to identify sufficiently discriminatory procedures that in turn would provide data to set meaningful specifications. Additional information obtained from successful in vitro-in vivo correlations (IVIVC) and accelerated drug release tests are extremely useful during drug product development. Although several workers have employed different methods to monitor drug release from these dosage forms, the use of the compendial Apparatus 4 (flow-through) device has been recommended in a publication on FIP/AAPS Guidelines for drug release testing of modified release dosage forms. However, most of method development with this device has focused on oral immediate or controlled release dosage forms and little published information is available on implants. Two recent reports on workshops provide useful information on methods to evaluate drug release from controlled-release parenterals such as implants, including IVIVC and accelerated release testing. Details on such studies, however, are generally not found in the literature; possibly because of the high proprietary value of methodologies for establishing release specifications of implant dosage forms. This article reviews the current status of methodologies used in the investigation of drug release from subcutaneous implants with an emphasis on mechanistic, product development and regulatory perspectives.

A molecular model to explain paclitaxel and docetaxel sensitivity changes through adduct formation with primary amines in electrospray ionization mass spectrometry.

The objective of this study was to adopt a molecular modeling approach to understand changes in signal intensity due to adduct formation with short-chain alkylamines for two anticancer agents, paclitaxel and docetaxel, during electrospray mass spectrometric analysis. We describe a simple and intuitive modeling procedure using a comparison of hydropathic interaction (HINT) scores to explain differences in responses of amine adducts formed with the two analytes. The responses of paclitaxel and docetaxel were generally enhanced considerably (up to approximately 500% in some instances) on adding the amines. However, for the docetaxel adduct formed with added decylamine in the mobile phase, the response dropped by 32%. A mechanistic understanding for this behavior is proposed, and binding scores calculated from corresponding molecular models were found to be consistent with the trend obtained from mass spectrometric data.

Evaluation of deuterium isotope effects in normal-phase LC-MS-MS separations using a molecular modeling approach.

Molecular modeling of stationary phases presents a unique challenge because there is little available experimentally derived structural information. Verified interaction mechanisms at a molecular level with analytes are also rare. Molecular mechanics calculations using the Tripos force field were carried out to qualitatively and quantitatively assess stationary phase interactions. Binding energy values of -15.40, 15.28, -12.53, and -12.34 kcal/mol, respectively, are obtained for olanzapine (OLZ), OLZ-D3, des-methyl olanzapine (DES), and DES-D8 that corresponded to the retention behavior of the four compounds observed using liquid chromatography-mass spectrometry (MS)-MS. The model explains, semiquantitatively, the deuterium isotope effect in the normal-phase chromatographic separation of these compounds.