Formulation design, in vitro characterizations and anti-malarial investigations of artemether and lumefantrine-entrapped solid lipid microparticles.

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.

Polymeric in situ forming depots for long-acting drug delivery systems.

Polymeric in situ forming depots have emerged as highly promising drug delivery systems for long-acting applications. Their effectiveness is attributed to essential characteristics such as biocompatibility, biodegradability, and the ability to form a stable gel or solid upon injection. Moreover, they provide added versatility by complementing existing polymeric drug delivery systems like micro- and nanoparticles. The formulation's low viscosity facilitates manufacturing unit operations and enhances delivery efficiency, as it can be easily administered via hypodermic needles. The release mechanism of drugs from these systems can be predetermined using various functional polymers. To enable unique depot design, numerous strategies involving physiological and chemical stimuli have been explored. Important assessment criteria for in situ forming depots include biocompatibility, gel strength and syringeability, texture, biodegradation, release profile, and sterility. This review focuses on the fabrication approaches, key evaluation parameters, and pharmaceutical applications of in situ forming depots, considering perspectives from academia and industry. Additionally, insights about the future prospects of this technology are discussed.

Solidified Reverse Micellar Solution- (SRMS-) Based Microparticles for Enhanced Oral Bioavailability and Systemic Antifungal Efficacy of Miconazole Nitrate in Immunocompromised Mice.

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 LD50 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 µg/hr/mL) and B 1 (4.91 µg/hr/mL) while formulation C 1 (1.80 µg/hr/mL) had a lower AUC than MN (4.46 µg/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.

Formulation Development of Azadirachta indica Extract as Nanosuppository to Improve its Intrarectal Delivery for the Treatment of Malaria.

BACKGROUND: Previous folkloric and experimental reports have demonstrated the antimalarial efficacy of Azadirachta indica (AZA) extracts. However, one of the major challenges facing its application for the clinical treatment of malaria is the design of an acceptable dosage form. OBJECTIVE: Consequently, we developed AZA extract-loaded nanostructured lipid carriers (NLC) for the formulation of suppositories, denoted as nanosuppositories, for intrarectal treatment of malaria. METHODS: Various batches of NLC-bearing AZA extract were formulated based on lipid matrices prepared using graded concentrations of Softisan®154 and Tetracarpidium conophorum or walnut oil. NLC was investigated by size and differential scanning calorimetry (DSC). Suppository bearing AZA extract-loaded NLC was developed using cocoa butter or theobroma oil, and their physicochemical properties were profiled. In vitro drug release and in vivo antimalarial activity (using Plasmodium berghei-infected mice) were investigated. RESULTS: NLCs exhibited sizes in nanometers ranging from 329.5 - 806.0 nm, and were amorphized as shown by DSC thermograms. Nanosuppositories were torpedo- or bullet- shaped, weighing 138 - 368 mg, softened/liquefied between 4.10 - 6.92 min, and had controlled release behaviour. In vivo antimalarial study revealed excellent antimalarial efficacy of the nanosuppositories comparable with a commercial brand (Plasmotrim®) and better than the placebo (unloaded nanosuppository), and without toxic alterations of hepatic and renal biochemical factors. CONCLUSION: Thus, AZA extract could be rationally loaded in nanostructured lipid carriers (NLC) for further development as nanosuppository and deployed as an effective alternative with optimum convenience for intrarectal treatment of malaria.

Emergency medicine: magnesium sulphate injections and their pharmaceutical quality concerns.

OBJECTIVES: World Health Organization has recognized magnesium sulphate as the drug of choice for prevention and treatment of fits associated with preeclampsia and eclampsia which are amongst the leading causes of maternal morbidity and mortality. In this study, the pharmaceutical quality of magnesium sulphate injections marketed in Anambra state was assessed. METHODS: Ninety samples of magnesium sulphate obtained from the 3 senatorial zones in Anambra state were subjected to identification tests, microbiological analysis consisting of Growth promotion test, sterility and endotoxin test. Content analysis using titrimetric method and pH analysis were also carried out on the samples. RESULTS: Twenty percent (20%) of samples obtained from Onitsha failed identification test as they had no Registration number in Nigeria. All samples subjected to the microbiology tests (sterility and endotoxin test) passed. Twenty percent (20%) and thirty-three percent (33.3%) of samples sourced from Onitsha and Nnewi respectively failed the pH analysis test. All the samples passed microbiological tests and had their Active Pharmaceutical Ingredients (API) within the acceptable limit. CONCLUSIONS: This study reveals that there are still some substandard magnesium sulphate injections in circulation in the locality. The supply chain of these drugs should be monitored to ensure a reduction in the incidences of substandard magnesium sulphate and positive therapeutic outcome which translates to reduced maternal mortality associated with pre-eclampsia and eclampsia in Nigeria.

Development of lipid-based microsuspensions for improved ophthalmic delivery of gentamicin sulphate.

Aim: Anterior eye segment disorders are treated with eye drops and ointments, which have low ocular bioavailability necessitating the need for improved alternatives. Lipid microsuspension of gentamicin sulphate was developed for the treatment of susceptible eye diseases. Materials & methods: Lipid microsuspensions encapsulating gentamicin sulphate were produced by hot homogenization and evaluated. Ex vivo permeation and ocular irritancy tests were also conducted. Results & conclusion: Stable microsuspensions with high entrapment efficiency and satisfactory osmolarities were obtained. Release studies achieved 49-88% in vitro release at 12 h with sustained permeability of gentamicin compared with conventional gentamicin eye drop (Evril®). No irritation was observed following Draize's test. The microsuspensions have great potential as ocular delivery system of gentamicin sulphate.

Development Insights of Surface Modified Lipid Nanoemulsions of Dihydroartemisinin for Malaria Chemotherapy: Characterization, and in vivo Antimalarial Evaluation.

BACKGROUND: The use of dihydroartemisinin (DHA) for effective malaria treatment is challenged by its poor aqueous solubility and inadequate bioavailability leading to treatment failures and emergence of resistant strains. A review of some novel drug delivery systems developed to address these challenges and their patents revealed that no study has reported the application of surface modified lipid nanoemulsions for improved antimalarial activity of DHA. OBJECTIVE: The main thrust of this study is to develop oral dihydroartemisinin formulations solubilized in surface modified lipid nanoemulsions, characterize, and evaluate their activity against murine malaria. METHOD: Lipid nanoemulsions containing dihydroartemisinin were formulated by high pressure homogenization using soybean oil, and polyethylene glycol 4000 was employed for surface modification. The formulations were characterized for droplet size, surface charge, pH, fouriertransform infrared spectroscopy, and surface morphology, viscosity and drug content efficiency. In vitro haemolytic study as a function of cytotoxicity using red blood cells as well as in vivo anti-malarial study using murine malaria model was also investigated. RESULTS: Nanoemulsions recorded droplet sizes ranging from 26 - 56 nm, and zeta potential in the range of -28 to -35 mV. The formulations were slightly acidic (pH 4.4 - 5.8) with the drug molecularly dispersed as seen using infrared spectroscopy. The formulations showed non- Newtonian flow with significant drug content efficiency in the range of 77-96%. The formulations did not induce haemolysis of cells and showed good clearance of parasitaemia. CONCLUSION: Surface-modified lipid nanoemulsion is a perfect carrier system for improving the anti-malarial activity of dihydroartemisinin.

Surface-modified mucoadhesive microgels as a controlled release system for miconazole nitrate to improve localized treatment of vulvovaginal candidiasis.

The use of conventional vaginal formulations of miconazole nitrate (MN) in the treatment of deep-seated VVC (vulvovaginal candidiasis) is limited by poor penetration capacity and low solubility of MN, short residence time and irritation at the application site. Surface-modified mucoadhesive microgels were developed to minimize local irritation, enhance penetration capacity and solubility and prolong localized vaginal delivery of MN for effective treatment of deep-seated VVC. Solid lipid microparticles (SLMs) were prepared from matrices consisting of hydrogenated palm oil (Softisan® 154, SF) and super-refined sunseed oil (SO) with or without polyethylene glycol (PEG)-4000, characterized for physicochemical performance and used to prepare mucoadhesive microgels (MMs) encapsulating MN, employing Polycarbophil as bioadhesive polymer. The MMs were evaluated for physicochemical performance and in vitro drug release in simulated vaginal fluid (pH=4.2), whereas mucoadhesive, rheological and stability tests, anticandidal efficacy in immunosuppressed estrogen-dependent female rats and vaginal tolerance test in rabbits were performed with optimized formulation. The amorphicity of 1:9 phytolipid blend (SO:SF) was increased in the presence of PEG-4000. The physicochemical properties of the SLMs and MMs indicated their suitability for vaginal drug delivery. Overall, MN-loaded PEGylated MMs exhibited significantly (p<0.05) more prolonged drug release than non-PEGylated MMs. Additionally, optimized PEGylated MMs was stable at 40±2°C over a period of 6months, viscoelastic, mucoadhesive, non-sensitizing, histopathologically safe and gave remarkably (p<0.05) higher reduction in Candida albicans load (86.06%) than Daktarin® (75.0%) and MN-loaded polymeric-hydrogel (47.74%) in treated rats in 12days. Thus, PEGylated MMs is promising for effective and convenient treatment of VVC.

Novel Intravaginal Drug Delivery System Based on Molecularly PEGylated Lipid Matrices for Improved Antifungal Activity of Miconazole Nitrate.

The aim of this study was to investigate the potential of microparticles based on biocompatible phytolipids [Softisan® 154 (SF) (hydrogenated palm oil) and super-refined sunseed oil (SO)] and polyethylene glycol- (PEG-) 4000 to improve intravaginal delivery of miconazole nitrate (MN) for effective treatment of vulvovaginal candidiasis (VVC). Lipid matrices (LMs) consisting of rational blends of SF and SO with or without PEG-4000 were prepared by fusion and characterized and employed to formulate MN-loaded solid lipid microparticles (SLMs) by melt-homogenization. The SLMs were characterized for physicochemical properties, anticandidal activity, and stability. Spherical discrete microparticles with good physicochemical properties and mean diameters suitable for vaginal drug delivery were obtained. Formulations based on SO:SF (1:9) and containing highest concentrations of PEG-4000 (4 %w/w) and MN (3.0 %w/w) were stable and gave highest encapsulation efficiency (83.05-87.75%) and inhibition zone diameter (25.87±0.94-26.33±0.94 mm) and significantly (p<0.05) faster and more powerful fungicidal activity regarding killing rate constant values (7.10 x 10-3-1.09 x 10-2 min-1) than commercial topical solution of MN (Fungusol®) (8.00 x 10-3 min-1) and pure MN sample (5.160 x 10-3 min-1). This study has shown that MN-loaded SLMs based on molecularly PEGylated lipid matrices could provide a better option to deal with VVC.

Profiling the physicochemical and solid state properties of edible Tetracarpidium conophorum oil and its admixtures for drug delivery

Abstract The study is aimed at investigating the functional physicochemical and solid state characteristics of food-grade Tetracarpidium conophorum (T. conophorum) oil for possible application in the pharmaceutical industry for drug delivery. The oil was obtained by cold hexane extraction and its physicochemical properties including viscosity, pH, peroxide, acid, and thiobarbituric acid values, nutrient content, and fatty acid profile were determined. Admixtures of the oil with Softisan®154, a hydrogenated solid lipid from palm oil, were prepared to obtain matrices which were evaluated by differential scanning calorimetry, fourier-transform infrared spectroscopy, and x-ray diffractometry. Data from the study showed that T. conophorum oil had Newtonian flow behaviour, acidic pH, insignificant presence of hyperperoxides and malondialdehyde, contains minerals including calcium, magnesium, zinc, copper, manganese, iron, selenium, and potassium, vitamins including niacin (B3), thiamine (B1), cyanocobalamine (B12), ascorbic acid (C), and tocopherol (E), and long-chain saturated and unsaturated fatty acids including n-hexadecanoic acid, 9(Z)-octadecenoic acid, and cis-13-octadecenoic acid. The lipid matrices had low crystallinity and enthalpy values with increased amorphicity, and showed no destructive intermolecular interaction or incompatibility between T. conophorum oil and Softisan® 154. In conclusion, the results have shown that, in addition to T. conophorum oil being useful as food, it will also be an important excipient for the development of novel, safe, and effective lipid-based drug delivery systems.

Development, in vitro and in vivo evaluations of novel lipid drug delivery system of Newbouldia laevis (P. Beauv.).

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.

Formulation design and in vitro physicochemical characterization of surface modified self-nanoemulsifying formulations (SNEFs) of gentamicin.

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.

The use of solid lipid nanoparticles for sustained drug release.

Novel solid lipid drug delivery systems such as solid lipid nanoparticles (SLN) have attracted wide and increasing attention in recent years. It has been sought as an interesting alternative drug delivery carrier system for bioactives for a variety of delivery routes. They show major advantages such as sustained release, improved bioavailability, improved drug incorporation and very wide application. This paper presents a discussion on the production protocols of SLN, lyophilization of SLN and delivery of SLN across the blood-brain barrier. Special attention was also paid to entrapment and release of drugs from SLN and strategies to enhance drug entrapment in SLN for sustained release. Analytical methods for the characterization of SLN were also discussed. Various routes of administration of SLN were presented as well as a consideration of the ethical issues and future prospects in the production and use of SLN for sustained release of bioactives.

Molecular interaction between glimepiride and Soluplus®-PEG 4000 hybrid based solid dispersions: Characterisation and anti-diabetic studies.

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.

Physico-Technical Properties of Tablets Formulated with Ethanolic Extract of Fresh Leaves of Combretum Micranthum G. Don.

This study is a follow-up to our recent study published elsewhere. It is aimed at determining the physico – technical and antibacterial profiles of tablets formulated using ethanolic extracts of Combretum micranthum, and also determine if they meet pharmacopoeial specifications. The fresh leaves of Combretum micranthum were harvested during the rainy season in Akwa Ibom State, Nigeria. They were thoroughly washed and rinsed with distilled water, divided into three portions, and dried in hot air oven at 48 ºC (Sample A), sun (Sample B) and at room temperature (Sample C). They were pulverized, macerated in a transparent extraction tank using 70 % ethanol for 72 h at room temperature, and concentrated. The activity of each extract was tested on typed cultures of Staphylococcus aureus (ATCC 6538) and Escherichia coli (ATCC 25922). The extract with the highest activity (Sample B) was selected for further studies. Phytochemical screening was carried out using standard methods. Six batches of granulations for tablets were produced using a predetermined formula. The flow rate, angle of repose, and compressibility indices of the granules were determined, and uniformity of weight, hardness, friability and disintegration time of the tablets were determined using pharmacopoeial methods. The results show that the sun-dried leaves of C. micranthum have constituents that exhibited the highest activity against cultures of S. aureus and E. coli. The phytochemical screening on the sun-dried leaves extract revealed that tannins were present in large quantities while phlobatannins and anthraquinones were absent. The results of the flow and compressibility properties of the granules from sun-dried extract revealed generally poor flow and high compressibility for all the batches. The tablet hardness values for all the batches were greater than 5 kg. The friability value for each batch was less than 1 %. The tablets have maximum disintegration time of 101 min. These results showed that the extract could be used to produce sustained release or delayed release tablets.