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Mosquitoes are the most medically important arthropod vectors of several human diseases. These diseases are known to severely incapacitate and debilitate millions of people, resulting in countless loss of lives. Over the years, several measures have been put in place to control the transmission of mosquito-borne diseases, one of which is using repellents. Repellents are one of the most effective personal protective measures against mosquito-borne diseases. However, conventional delivery systems of repellents ( e.g. , creams, gels, and sprays) are plagued with toxicity and short-term efficacy issues. The application of biopolymeric and lipid-based systems has been explored over the years to develop better delivery systems for active pharmaceutical ingredients including mosquito repellents. These delivery systems ( e.g. , solid lipid micro/nanoparticles, micro/nanoemulsions, or liposomes) possess desirable properties such as high biocompatibility, versatility, and controlled/sustained drug delivery, and thus are very important in tackling the clinical challenges of conventional repellent systems. Their capability for controlled/sustained drug release has improved patient compliance as it removes the need for consistent reapplication of repellents. They can also be engineered to reduce repellents' skin permeation, consequently improving their safety. However, despite the benefits that these systems offer very few of them have been successfully translated to the global market for commercial use, a vital challenge that previous reports have not thoroughly examined. The issue of limited clinical translation of novel repellent systems is a vital aspect to consider, as the ultimate goal is to move these systems from bench to bedside. As such, this study seeks to highlight the recent advances in the use of biopolymeric and lipid-based systems for the development of novel mosquito-repellent systems and also analyze the challenges that have limited the clinical translation of these systems while proposing possible strategies to overcome these challenges., Competing Interests: The authors declare no conflict of interest., (This journal is © The Royal Society of Chemistry.)

Purpose: To assess the improvement in oral bioavailability and efficacy in systemic candidiasis treatment of miconazole nitrate (MN) formulations in murine models of candidiasis., Methods: Selected formulations containing 5% of Softisan + Phospholipon 90H lipid matrix with 3% of MN ( A 1 ), 5% of stearic acid + Phospholipon 90H lipid matrix with 3% of MN ( B 1 ), and 5% Softisan + stearic acid + Phospholipon 90H with 3% of MN ( C 1 ) from the in vitro investigation were used for the study. Their acute toxicity was assessed using Lorke's method (with slight modification) while bioavailability was determined using the bioassay method. The optimized batch ( A 1 ) was tested in murine systemic candidiasis induced in cyclophosphamide-immunosuppressed mice. The mice were treated with a single oral dose (100 mg/kg) of the formulations for five days. Serum fungal counts (cfu/mL) were determined on days 1, 3, and 5 of the treatment period. Haematological assessments were done., Results: The lipid formulations were safer than MN powder with LD 50 values of 3162.8 and 1118.3 mg/kg. Bioavailability determination revealed a higher area under the curve (AUC) value for formulations A 1 (6.11  μ g/hr/mL) and B 1 (4.91  μ g/hr/mL) while formulation C 1 (1.80  μ g/hr/mL) had a lower AUC than MN (4.46  μ g/hr/mL). Fungi were completely cleared from the blood of animals treated with the optimized formulation by day 3 as opposed to the controls (MN and Tween® 20) which still had fungi on day 5. No significant increase ( p > 0.05) in haematological parameters was observed in mice treated with A 1 ., Conclusion: Formulation A 1 successfully cleared Candida albicans from the blood within a shorter period than miconazole powder. This research has shown the potential of orally administered MN-loaded SRMS-based microparticles in combating systemic candidaemia., Competing Interests: The authors declare no competing interests in the research work., (Copyright © 2022 Emmanuel Maduabuchi Uronnachi et al.)

Newbouldia laevis (P. Beauv.) is a tropical rainforest plant used in traditional folk medicine for the treatment of malaria, cough, joint pains, stomach ache, oedema and inflammation. The main thrust of this research work was to study the analgesic/anti-nociceptive properties of N. laevis -loaded solid lipid microdispersions. N. laevis leaves were extracted using ethanol, and the extract was formulated into solid lipid microdispersions using lipid matrix comprising a rational blend of Precirol ® ATO 5 and Softisan ® 154. Characterization of the solid lipid microdispersions include determination of morphology, particle size, pH, thermal property, encapsulation efficiency percentage and analgesic/anti-nociceptive property. The results obtained showed that the particles were spherical with sizes ranging from 40 µm to 125 µm. The solid lipid microdispersions maintained a stable pH within the acidic region of 5-6 with insignificant variations ( p > 0.05) over a period of 90 days. Thermal analysis showed that N. laevis was entrapped in the lipid matrix used for the formulations. Solid lipid microdispersions recorded a maximum encapsulation efficiency up to 88.1%. N. laevis -loaded solid lipid microdispersions also produced good analgesic/anti-nociceptive property comparable with the standard diclofenac potassium. N. laevis -loaded solid lipid microdispersions showed good analgesic/anti-nociceptive effect and could be used in the treatment and management of pain., Competing Interests: Declaration of conflicting interests: The author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Context: Poor aqueous solubility of artemether and lumefantrine makes it important to seek better ways of enhancing their oral delivery and bioavailability., Objective: To formulate and carry out in vitro and anti-malarial pharmacodynamic evaluations of solidified reverse micellar solutions (SRMS)-based solid lipid microparticles (SLMs) of artemether and lumefantrine for oral delivery and improved bioavailability., Materials and Methods: Rational blends of Softisan(®)154 and Phospholipon(®)90H lipid matrices, and different concentrations of artemether and lumefantrine were used to formulate several batches of SLMs. Drug-free SLMs were also formulated. Morphology, particle size, encapsulation efficiency (EE%) and pH studies were performed. In vitro release studies were performed in alcoholic buffer, simulated gastric fluid (SGF) and simulated intestinal fluid (SIF) without enzymes. Anti-malarial pharmacodynamic studies were conducted in mice., Results: Stable, smooth and spherical particles with sizes ranging from 4.2 ± 0.02 to 9.3 ± 0.8 µm were formed. EE% of 92.2-97.3% and 30.2-84.7% and pH of 3.0 ± 0.02 to 4.9 ± 0.12 and 3.0 ± 0.02 to 5.8 ± 0.05 were obtained for artemether and lumefantrine SLMs, respectively. Release of 100, 88.28 and 75.49%, as well as 63.26, 34.31 and 56.17% were recorded for artemether and lumefantrine in alcoholic buffer, SGF and SIF, respectively. Pharmacodynamic studies indicated very significant (p < 0.05) clearance of parasitaemia in plasmodium-infected mice by the drug-loaded SLMs., Conclusion: Oral delivery and bioavailability of artemether and lumefantrine could be improved using SRMS-based SLMs.

Self-nanoemulsifying formulations (SNEFs) structured with PEG 4000 as PEGylated SNEFs, were formulated after solubility studies using rational blends of soybean oil, a combination of Kolliphor(®) EL and Kolliphor(®) P188 as surfactants, and Transcutol(®) HP as co-surfactant, and evaluated for oral delivery of gentamicin. Incorporation of gentamicin and PEG 4000 reduced the initial area of nanoemulsion of the ternary phase diagrams produced by water titration method using oil, surfactant mixture and co-surfactant. Emulsion droplets were in the nanometer scale ranging from 80-210 nm. FT-IR study revealed that gentamicin structure remained intact in all formulations, and SEM micrographs showed spherical globules. Zeta potentials of SNEFs were in the range of -25.4 to -42.5 mV, and showed a stable system with minor flips in electrostatic charges. There was high in vitro diffusion-dependent permeation of gentamicin from the SNEFs. Results obtained in this work showed that oral delivery of gentamicin was improved by formulation as surface modified SNEFs., (Copyright © 2015 Elsevier B.V. All rights reserved.)

The objective of this study was to evaluate a novel blend of polyvinyl caprolactam-polyvinyl acetate-polyethylene glycol 6000 grafted copolymer (Soluplus®) and polyethylene glycol (PEG) 4000 for solubility enhancement, physicochemical stability and anti-diabetic efficacy of the produced solid dispersions containing glimepiride, a biopharmaceutics classification system (BCS) class II sulphonylurea. Different batches of glimepiride solid dispersions (SD) were prepared by the solvent evaporation method using the individual polymers and blends of the polymers at different ratios. The Soluplus®-PEG 4000 (sol-PEG) hybrid polymer based glimepiride solid dispersions were characterized by differential scanning calorimetry (DSC), fourier transform infrared (FTIR) spectroscopy, micromeritics and dissolution studies. In vivo anti-diabetic activity was determined by measuring the changes in blood glucose concentrations in albino rats. The solid dispersions showed good flow properties and excellent practical yield. Drug content and release from the different formulations increased when Soluplus® was used as the main matrix polymer. The kinetics of drug release from all the solid dispersions followed first order. Solid state characterization confirmed the formation of amorphous glimepiride solid dispersions in the Sol-PEG hybrid polymer and no strong drug-polymer interaction was observed. The blood glucose reduction in albino rats by the Sol-PEG-Glim SDs was significantly (p<0.05) higher and more sustained when compared with the plain drug sample and commercially available product. Optimized SD batches (SP1 and SP3) showed a reduction in blood glucose level from 100% to 9.81% and 8.97%, respectively, at Tmax of 3h. The Sol-PEG-Glim SD was found to be stable over a period of 6 months (at 40°C, 70% RH) with no significant changes in the drug content. Thus, the Sol-PEG polymeric hybrids represent a promising tool for enhanced delivery of glimepiride., (Copyright © 2015 Elsevier B.V. All rights reserved.)