In vitro redox activity of haemozoin and ß-haemozoin interacting with the following antimalarials: artemether, lumefantrine and quinine.

OBJECTIVE: Malaria parasites invade, grow and multiply inside erythrocytes and obtain nourishment from haemoglobin. Then, the released haem group is oxidized to haematin and inert dimeric haemozoin bio-crystals form, which provides the parasite a unique way to avoid the toxicity associated with the haem group. Therefore, antimalarial drugs are designed to inhibit dimer formation; however, recent electrochemical studies indicate that an inert dimer also promotes a toxic oxidizing environment. Therefore, this work explores drug reactivity in the presence of monomers and dimers to evaluate their contribution to redox activity. MATERIALS AND METHODS: Three medicines mixed with haemozoin or ß-haemozoin in carbon paste electrodes were tested using cyclic voltammetry. RESULTS: The data indicated again that the substances modify the natural redox state of haemozoin and ß-haemozoin. This effect could be attributed to the natural oxidation potential of the drugs. In addition, it was found that the oxidation potential decreased through quinine, lumefantrine and artemether with the same tendency in the presence of haemozoin but with less current density. Additionally, it was observed that the oxidation response between the monomer haemozoin and antimalarial drugs is carried out at more negative potentials. CONCLUSIONS: Together, the total results indicate that antimalarials per se can contribute to oxidation processes and that in combination with monomeric or dimeric haemozoin can increase or decrease the oxidizing power of the haemozoin forms. The various oxidizing environments suggest that the cell membranes can also be damaged by the unique presence of the antimalarial.

Characterization of solid lipid dispersions prepared by hot fusion containing a double-fixed dose combination of artemether and lumefantrine.

OBJECTIVE: The World Health Organization has called for the development of novel drug delivery systems to combat malaria - the fourth most prevalent cause of death globally. The plausibility of utilizing hot fusion to prepare solid lipid dispersions containing the prescribed first-line, double-fixed dose combination (artemether and lumefantrine), proposed for inclusion in directly compressed lipid matrix tablets, was investigated. Significance: Currently, no anti-malarial product is commercially available that employs lipid technology in a solid oral dosage form that contains this double-fixed dose combination. Through developing lipid matrix tablets, the stability, solubility and subsequent bioavailability of these drugs could be significantly enhanced in the presence of lipids or oils. METHODS: Hot fusion encompasses encompassed melt mixing of a selected lipid base and the dispersion of the active ingredient(s) therein below their glass transition temperatures. Solid-state characterization, particle size analysis and pharmacotechnical properties were evaluated, with particular focus given to powder flowability. RESULTS: Stearic acid in a 0.5:1 lipid:drug ratio demonstrated the best powder flow properties of the investigated solid lipid dispersion for inclusion into prospective lipid-matrix tablets duly based on an increase in overall particle size, a more spherical particle shape and improved powder flow properties compared to the individual active ingredients. CONCLUSION: Good powder flow is critical for powders destined for inclusion into tablets - especially when employing direct compression as method of manufacture - in this case, lipid matrix tablets, which have demonstrated huge promise as a prospective dosage form for future use in malarial treatment.

Enantioselective LC-ESI-MS/MS method for quantitation of (-)-lumefantrine and (+)-lumefantrine in mice plasma and application to a pharmacokinetic study.

We developed and validated a simple, sensitive, selective, and reliable LC-MS/MS-ESI method for the direct quantitation of lumefantrine (LFN) enantiomers [(-)-LFN and (+)-LFN] in mice plasma as per regulatory guideline. LFN enantiomers and carbamazepine (internal standard) were extracted from mice plasma using Strata X SPE (solid-phase extraction) cartridges. Good resolution between enantiomers was achieved on a Chiralpak IA-3 column using an isocratic mobile phase (0.1% of diethyl amine in methanol), which was delivered at a flow rate of 0.8 mL/min. Detection and quantitation were performed using multiple reaction monitoring mode following the transitions m/z 530.27 → 512.30 and 237.00 → 194.00 for LFN enantiomers and the internal standard, respectively, in the positive-ionization mode. The proposed method provided accurate and reproducible results over the linearity range of 2.39-895 ng/mL for each enantiomer. The intra- and inter-day precisions were in the range of 1.03-6.14 and 6.36-8.70 and 2.03-4.88 and 5.82-11.5 for (-)-LFN and (+)-LFN, respectively. Both (-)-LFN and (+)-LFN were found to be stable under different stability conditions. The method was successfully used to delineate stereoselective pharmacokinetics of LFN enantiomers in mice after an oral administration of rac-LFN (20 mg/kg). The pharmacokinetic results indicated that the disposition of LFN enantiomers was stereoselective in mice.

22 factorial design-based biocompatible microneedle arrays containing artemether co-loaded with lumefantrine nanoparticles for transepidermal delivery.

The present study was intended to enhance the permeation of artemether and lumefantrine by encapsulating in dissolvable microneedle arrays for extended action. Lumefantrine-nanoparticles were synthesized using chitosan mediated gelation and optimized by 22 factorial designs. The particle size, zeta potential and % entrapment efficiency of the optimized nanoparticles F5 were 105 ± 3.64 nm, 24.4 ± 0.54 mV and 83.94 ± 1.71%, respectively. The nanoparticles showed a controlled-release of 79.15 ± 2.45% for lumefantrine after 24 h and stability for 6 months. A combination of biocompatible polymers (PVA and PVP K - 12) was used to develop dissolvable microneedle of artemether co-loaded lumefantrine nanoparticles. The SEM and TEM analysis confirmed the needle-shaped morphology with a size of 672 ± 0.99 µm. The in-vitro release of microneedle showed biphasic release pattern for both artemether and lumefantrine, with an initial burst followed by controlled-release profile. The ex-vivo study of optimized formulation showed 70.94 ± 2.45% and 65.87 ± 1.94% permeation for artemether and lumefantrine, respectively, after 24 h. Thus, microneedle-based delivery provides an alternative to painful intravenous administration and a promising approach to increase the penetration of drugs across the skin barrier. Graphical abstract Fabrication of microneedle arrays of artemether co-loaded with lumefantrine nanoparticles.

Low-Frequency Raman Scattering Spectroscopy as an Accessible Approach to Understand Drug Solubilization in Milk-Based Formulations during Digestion.

Techniques enabling in situ monitoring of drug solubilization and changes in the solid-state of the drug during the digestion of milk and milk-based formulations are valuable for predicting the effectiveness of such formulations in improving the oral bioavailability of poorly water-soluble drugs. We have recently reported the use of low-frequency Raman scattering spectroscopy (region of analysis <200 cm-1) as an analytical approach to probe solubilization of drugs during digestion in milk using ferroquine (SSR97193) as the model compound. This study investigates the wider utilization of this technique to probe the solubilization behavior of other poorly water-soluble drugs (halofantrine, lumefantrine, and clofazimine) in not only milk but also infant formula in the absence or presence of bile salts during in vitro digestion. Multivariate analysis was used to interpret changes to the spectra related to the drug as a function of digestion time, through tracking changes in the principal component (PC) values characteristic to the drug signals. Characteristic low-frequency Raman bands for all of the drugs were evident after dispersing the solid drugs in suspension form in milk and infant formula. The drugs were generally solubilized during the digestion of the formulations as observed previously for ferroquine and correlated with behavior determined using small-angle X-ray scattering (SAXS). A greater extent of drug solubilization was also generally observed in the infant formula compared to milk. However, in the case of the drug clofazimine, the correlation between low-frequency Raman scattering and SAXS was not clear, which may arise due to background interference from clofazimine being an intense red dye, which highlights a potential limitation of this new approach. Overall, the in situ monitoring of drug solubilization in milk and milk-based formulations during digestion can be achieved using low-frequency Raman scattering spectroscopy, and the information obtained from studying this spectral region can provide better insights into drug solubilization compared to the mid-frequency Raman region.

HPLC-UV method for simultaneous quantitation of artemether and lumefantrine in fixed dose combination orodispersible tablet formulation.

This paper describes the development and validation of a high performance liquid chromatography (HPLC-UV) method for the simultaneous quantitative determination of artemether and lumefantrine in fixed dose combination tablets. Chromatographic quantitation was carried out on a C-18 column Mediterrania Sea 18 (250×4.6 mm i.d.; 5 µm particle size) using a mobile phase consisting of 80:20 v/v mixture of acetonitrile and 0.05 % trifluoroacetic acid with final pH adjusted to 2.35 at flow rate of 1 ml/minute. The eluents was detected using photo diode array detector at wavelength of 210nm for artemether and 286 nm for lumefantrine. The retention times were ~5.8 mins for artemether and ~7.3 mins for lumefantrine. The newly developed method was validated and was found linear (r2 >0.99), precise (R.S.D. <2.0%), accurate, specific and robust. The artemether contents in the tablet formulation varied from 99.026 % to 99.347%, while lumefantrine contents were 99.546-99.728 %.

Translational formulation of nanoparticle therapeutics from laboratory discovery to clinical scale.

BACKGROUND: "Nanomedicine" is the application of purposely designed nano-scale materials for improved therapeutic and diagnostic outcomes, which cannot be otherwise achieved using conventional delivery approaches. While "translation" in drug development commonly encompasses the steps from discovery to human clinical trials, a different set of translational steps is required in nanomedicine. Although significant development effort has been focused on nanomedicine, the translation from laboratory formulations up to large scale production has been one of the major challenges to the success of such nano-therapeutics. In particular, scale-up significantly alters momentum and mass transfer rates, which leads to different regimes for the formation of nanomedicines. Therefore, unlike the conventional definition of translational medicine, a key component of "bench-to-bedside" translational research in nanomedicine is the scale-up of the synthesis and processing of the nano-formulation to achieve precise control of the nanoscale properties. This consistency requires reproducibility of size, polydispersity and drug efficacy. METHODS: Here we demonstrate that Flash NanoPrecipitation (FNP) offers a scalable and continuous technique to scale up the production rate of nanoparticles from a laboratory scale to a pilot scale. FNP is a continuous, stabilizer-directed rapid precipitation process. Lumefantrine, an anti-malaria drug, was chosen as a representative drug that was processed into 200 nm nanoparticles with enhanced bioavailability and dissolution kinetics. Three scales of mixers, including a small-scale confined impinging jet mixer, a mid-scale multi-inlet vortex mixer (MIVM) and a large-scale multi-inlet vortex mixer, were utilized in the formulation. The production rate of nanoparticles was varied from a few milligrams in a laboratory batch mode to around 1 kg/day in a continuous large-scale mode, with the size and polydispersity similar at all scales. RESULTS: Nanoparticles of 200 nm were made at all three scales of mixers by operating at equivalent Reynolds numbers (dynamic similarity) in each mixer. Powder X-ray diffraction and differential scanning calorimetry demonstrated that the drugs were encapsulated in an amorphous form across all production rates. Next, scalable and continuous spray drying was applied to obtain dried powders for long-term storage stability. For dissolution kinetics, spray dried samples produced by the large-scale MIVM showed 100% release in less than 2 h in both fasted and fed state intestinal fluids, similar to small-batch low-temperature lyophilization. CONCLUSIONS: These results validate the successful translation of a nanoparticle formulation from the discovery scale to the clinical scale. Coupling nanoparticle production using FNP processing with spray drying offers a continuous nanofabrication platform to scale up nanoparticle synthesis and processing into solid dosage forms.

pH responsive delivery of lumefantrine with calcium phosphate nanoparticles loaded lipidic cubosomes for the site specific treatment of lung cancer.

The present work aim to develop pH responsive nanosystem comprising lumefantrine with calcium phosphate nanoparticles loaded lipidic cubosomes for the effective treatment of lung cancer. FTIR results showed that, compatibility nature of selected excipients for the synthesis of LF-CaP-Cs. The XRD results showed developed LF-CaP-Cs were non crystalline in nature. The selected developed LF-CaP-Cs were in cubic phase with average particle size of 259.4 ± 19 nm with a charge of -2.28 ± 0.7 mV. The encapsulation efficiency for LF within LF-CaP-Cs was about 78.76 ± 0.5%. RP-HPLC analysis showed that LF release rate gets significantly enhanced with higher peak area at pH 4.0 compared to pH 5.0/pH 7.4. The in-vitro release of LF-CaP-Cs showed that LF release gets significantly increased at pH 4.0 (84.04 ± 0.4%) compared to pH 7.4 (48.32 ± 1.6%) at 12 h. Further, CAM assay showed the superior anti-angiogenesis potential of developed LF-CaP-Cs compared to LF-Cs/blank Cs. The cytotoxicity effect of LF-CaP-Cs (28 ± 1.8 µg/mL) was significantly higher than that of free LF (40 ± 0.9 µg/mL). The results of cellular uptake study proved the localization of LF at cellular level and AO/EB staining results revealed that the A549 cell undergoes apoptosis in A549 cells.

Quality of the antimalarial medicine artemether - lumefantrine in 8 cities of the Democratic Republic of the Congo.

In the context of post-marketing surveillance supporting public-health authorities to take evidence-based decisions to fight the spread of poor-quality medicines, the quality of antimalarial artemether-lumefantrine (AL) medicines was assessed in the Democratic Republic of the Congo (DRC). A total of 150 samples of AL-containing products was collected from private pharmaceutical outlets in 8 main cities: Goma, Kikwit, Kinshasa, Kisangani, Lubumbashi, Matadi, Mbandaka, and Mbuji-Mayi. All drug samples were successively analyzed by visual inspection, thin-layer chromatography (TLC), and high-performance liquid chromatography (HPLC) following The International Pharmacopoeia. Of the 150 collected drug samples, 3 (2%) failed the visual inspection as they had shelf lives different from those of other samples with the same brand name. Four samples (2.7%) did not pass the TLC test as they contained only 1 or even none of the 2 declared active pharmaceutical ingredients (APIs). HPLC assays showed that 46 (30.7%) samples had artemether contents below 90% and 17 (11.3%) above 110% of the content claimed on the label. For lumefantrine, 32 (21.7%) samples had contents below 90%, and 8 (5.3%) had contents above 110%. This survey in DRC gives evidence that poor-quality antimalarial medicines are widely present. Based on 3 detection techniques, the study shows the necessity to equip developing countries with modern techniques such as HPLC, which, if combined with affordable techniques like TLC, could provide a pertinent analytical strategy to combat drug counterfeiting and poor manufacturing.

Continuous Single-Step Wet Granulation with Integrated in-Barrel-Drying.

PURPOSE: It was investigated if continuous wet granulation and drying could be combined in a twin-screw granulator with the aim to provide (pre-)dried granules in a single-step process, i.e. in-barrel-drying. METHODS: To have a consistent and robust material propulsion mechanism, a twin-screw granulator was divided into two compartments. One compartment was operated at lower temperature to granulate and to pre-heat the material, while another compartment was operated at very high temperature to evaporate the granulation liquid as rapidly as possible. Design of experiments was used to investigate the in-barrel-drying process in detail. The process was further investigated for twin-screw wet granulation with API suspension feed, and compared against traditional fluidised-bed drying. Granule and compact properties were evaluated to study the process impact on the product quality. RESULTS: In-barrel-drying was demonstrated as feasible and yielded completely dried and granulated material at specific settings. The evaporation zone temperature and the processed mass of water were identified as key parameters to balance the evaporation capacity of the process and the material throughput. Granules and compacts showed an acceptable product quality. CONCLUSIONS: In-barrel-drying can be used to condense the wet granulation and drying process steps into one piece of equipment, thereby limiting or even omitting downstream drying process steps.