Preparation of novel solid lipid microparticles loaded with gentamicin and its evaluationin vitroandin vivo

Characterization and Hydrolysis Studies of a Prodrug Obtained as Ester Conjugate of Geraniol and Ferulic Acid by Enzymatic Way

Ferulic acid (Fer) and geraniol (Ger) are natural compounds whose antioxidant and anti-inflammatory activity confer beneficial properties, such as antibacterial, anticancer, and neuroprotective effects. However, the short half-lives of these compounds impair their therapeutic activities after conventional administration. We propose, therefore, a new prodrug (Fer-Ger) obtained by a bio-catalyzed ester conjugation of Fer and Ger to enhance the loading of solid lipid microparticles (SLMs) designed as Fer-Ger delivery and targeting systems. SLMs were obtained by hot emulsion techniques without organic solvents. HPLC-UV analysis evidenced that Fer-Ger is hydrolyzed in human or rat whole blood and rat liver homogenates, with half-lives of 193.64 ± 20.93, 20.15 ± 0.75, and 3.94 ± 0.33 min, respectively, but not in rat brain homogenates. Studies on neuronal-differentiated mouse neuroblastoma N2a cells incubated with the reactive oxygen species (ROS) inductor H2O2 evidenced the Fer-Ger ability to prevent oxidative injury, despite the fact that it appears ROS-promoting. The amounts of Fer-Ger encapsulated in tristearin SLMs, obtained in the absence or presence of glucose, were 1.5 ± 0.1%, allowing the control of the prodrug release (glucose absence) or to sensibly enhance its water dissolution rate (glucose presence). These new "green" carriers can potentially prolong the beneficial effects of Fer and Ger or induce neuroprotection as nasal formulations.

Enhanced anti-inflammatory and ulcerogenicity of Ibuprofen microsphere formulations using Irvingia wombolu fat (IRW) and moringa oil (MO) as co-lipids

Ibuprofen is a member of the propionic acid class of nonsteroidal anti-inflammatory drugs (NSAIDs) with anti-inflammatory, analgesic, and antipyretic activities used to relieve a variety of pains. The objective of this study was to formulate, characterize and evaluate the in vitro and in vivo properties of ibuprofen formulated as solid lipid microspheres (SLMs) for enhanced delivery. The mixtures of Irvingia wombolu fat (IRW) and moringa oil (MO) each with Phospholipon® 90G (PL90G) at the ratio of 2:1 w/w were prepared by fusion, characterized and used to prepare SLMs. The SLMS were thereafter evaluated using the following parameters: particle size and morphology, stability, and encapsulation efficiency EE (%). In vitro release was carried out in phosphate buffer (pH 7.4). The ibuprofen based SLMs were also evaluated for anti-inflammatory and anti-ulcer effects using animal models. The pH showed significant increase after two months of formulation with a maximum value of 6.4 while the EE obtained were 95.6, 89.4 and 61.6% for SLMs formulated with lipid matrix of Phospholipon® 90G (1% and 2%), and MO (1%) respectively. The in vitro release showed maximum release of 87.8 and 98.97% of the two different lipid-based formulations while anti-inflammatory effect was up to 89.90% after 5 h of inducing inflammation. The SLMs did not show any lesion thus conferring gastroprotection on the formulations. The SLMs exhibited good anti-inflammatory property with gastroprotective action.

Mechanistic insight into the bioactivity of prodigiosin-entrapped lipid nanoparticles against triple-negative breast, lung and colon cancer cell lines

This research investigates the potentials of prodigiosin(PG) derived from bacteria and its formulations against triple-negative breast (TNB), lung, and colon cancer cells. The PG was extracted from S. marcescens using continuous batch culture, characterized, and formulated into lyophilized parenteral nanoparticles (PNPs). The formulations were characterized with respect to entrapment efficiency (EE), DSC, FT-IR, TEM, and proton nuclear magnetic resonance (1H NMR) spectroscopy. In vitro drug release was evaluated in phosphate buffer (pH 7.4) while acute toxicity, hematological and histopathological studies were performed on rats. The in vitro cytotoxicity was evaluated against TNB (MCF-7), lung (A-549), and colon (HT-29) cancer cell lines. High EE (92.3 ± 12%) and drug release of up to 89.4% within 8 h were obtained. DSC thermograms of PG and PG-PNPs showed endothermic peaks indicating amorphous nature. The FT-IR spectrum of PG-PNPs revealed remarkable peaks of pure PG, indicating no strong chemical interaction between the drug and excipients. The TEM micrograph of the PG-PNPs showed nano-sized formulations (20-30 nm) whose particles were mostly lamellar and hexagonal structures. The 1H NMR result revealed the chemical structure of PG showing all assigned proton chemical shifts. Toxicity results of the PG and its formulation up to a concentration of 5000 mg/kg showed insignificant vacuolar changes of hepatocytes in the liver, with normal renal medulla and cortex in the kidney. The PG and PG-PNPs inhibited the growth of breast, lung, and colon cell lines. The nano-sized lipid formulation (PG-PNPs) showed potential in PG delivery and cancer treatments.

Comparison of the In Vitro Drug Release Methods for the Selection of Test Conditions to Characterize Solid Lipid Microparticles

The release profiles of active substances from microspheres are one of the most important features in solid lipid microparticles (SLM) characterization. Unfortunately, the results of the dissolution tests are largely dependent on the chosen method and test conditions, which in relation to novel dosage forms, such as dispersions of lipid microspheres, are not clearly defined in international compendiums and guidelines. This makes it impossible to compare the results of different studies. The aim of the research was to identify the factors most influencing the variability of the obtained results. An attempt was also made to select the most appropriate method for testing drug substance release from SLM. Various dissolution methods were employed (method I: without a membrane, method II: in a dialysis bag, and method III: in a Side-Bi-Side chamber), and the obtained release profiles of cyclosporine and indomethacin from SLM dispersions were compared. In addition to the effect of membranes, the types of acceptor fluids were also investigated. Significant differences were observed when testing the SLM formulations under various test conditions. The results were significantly influenced by the selected membrane, the acceptor fluid, or the difference in the concentrations of active substance between the donor and acceptor compartments. The burst effect observed in some experimental methods was not noticed in other conditions. At this stage, the method with a dialysis bag has been selected as the most suitable, while the methods without the membrane can only play a complementary role.

Development and formulation of antidiabetic property of Anarcadium occidantale-based solid lipid microparticles

Anacardium occidentale (AO) possesses potent anti-diabetic properties, owing to its high phytochemicals content. This study attempted to maximise the efficacy of AO by encapsulating it in a solid lipid microparticle (SLMs) formulation. Leaves of AO were extracted with water and formulated into SLMs using a lipid matrix composed of P90H and Dika fat. Characterisation of the SLMs include morphology, particle size, pH, encapsulation efficiency percentage, in vitro release and anti-diabetic properties. SLMs were spherical with sizes ranging from 16.7 ± 0.8 µm to 40.12 ± 2.34 µm and had a fairly stable pH over time. Highest drug entrapment was 87%_. Batch A₂ exhibited an even release of 89%, sustained over time, and a mean percentage reduction in glucose of 25.9% at 12 h after oral administration to study animals. Anacardium occidentale-loaded SLMs exhibited a good hypoglycaemic effect and can be used in the management of diabetes.

Effects of Microencapsulated Ferulic Acid or Its Prodrug Methyl Ferulate on Neuroinflammation Induced by Muramyl Dipeptide

Ferulic acid (Fer) is known for its antioxidant and anti-inflammatory activities, which are possibly useful against neurodegenerative diseases. Despite the ability of Fer to permeate the brain, its fast elimination from the body does not allow its therapeutic use to be optimized. The present study proposes the preparation and characterization of tristearin- or stearic acid-based solid lipid microparticles (SLMs) as sustained delivery and targeting systems for Fer. The microparticles were produced by conventional hot emulsion techniques. The synthesis of the methyl ester of Fer (Fer-Me) allowed its encapsulation in the SLMs to increase. Fer-Me was hydrolyzed to Fer in rat whole blood and liver homogenate, evidencing its prodrug behavior. Furthermore, Fer-Me displayed antioxidant and anti-inflammatory properties. The amount of encapsulated Fer-Me was 0.719 ± 0.005% or 1.507 ± 0.014% in tristearin or stearic acid SLMs, respectively. The tristearin SLMs were able to control the prodrug release, while the stearic acid SLMs induced a significant increase of its dissolution rate in water. Jointly, the present results suggest that the tristearin SLMs loaded with Fer-Me could be a potential formulation against peripheral neuropathic pain; conversely, the stearic acid SLMs could be useful for Fer-Me uptake in the brain after nasal administration of the formulation.

Franklin K, Díaz DD. A novel formulation design based on hetero-templated solid lipid microparticles to improve the solubility of anti-inflammatory piroxicam for oral administration

The aim of the work was to formulate piroxicam-loaded solid lipid microparticles (SLMs) using natural biodegradable lipids and to evaluate the in vitro and in vivo properties of the formulations.

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.

Intranasal artesunate-loaded nanostructured lipid carriers: A convenient alternative to parenteral formulations for the treatment of severe and cerebral malaria

Early treatment with parenteral antimalarials is key in preventing deaths and complications associated with severe and cerebral malaria. This can be challenging in 'hard-to-reach' areas in Africa where transit time to hospitals with facilities to administer drugs parenterally can be more than 6 h. Consequently, the World Health Organization has recommended the use of artesunate (ATS) suppositories for emergency treatment of patients, however, this treatment is only for children under 6 years. The intranasal route (INR) can provide a safe and effective alternative to parenteral and rectal routes for patients of all ages; thus, reducing delays to the initiation of treatment. Hence, we designed ATS-loaded nanostructured lipid carriers (NLCs) for intranasal administration. ATS-NLCs were formulated using varying concentrations of lipid matrices made up of solidified reverse micellar solutions (SRMS) comprising a 1:2 ratio of Phospholipon ® 90H and lipids (Softisan ® 154 or Compritol ®). ATS-NLCs were spherical, and the small sizes of ATS-NLCs obtained for some formulations (76.56 ± 1.04 nm) is an indication that ATS-NLCs can pass through the nasal mucosa and reach the brain or systemic circulation. Encapsulation efficiency of ATS in NLCs was ≥70% for all formulations. ATS-NLCs achieved up to 40% in vitro drug release in 1 h, while ex vivo permeation studies revealed that formulating ATS as NLCs enhanced permeation through pig nasal mucosa better than drug solution. Most importantly, the activity and reduction in parasitaemia [in mice infected with Plasmodium berghei ANKA in a murine cerebral malaria model] by ATS-NLCs administered through the INR (54.70%, 33.28%) was comparable to intramuscular administration (58.80%, 42.18%), respectively. Therefore, intranasal administration of NLCs of ATS has great potentials to serve as a satisfactory alternative to parenteral administration for the treatment of severe and cerebral malaria in both adults and children in remote areas of sub-Saharan Africa.

Formulation, characterization and statistical optimization of enalapril-loaded lipospheres

Lipid-based polymers have been proved efficient drug carriers for overcoming the insufficiencies of conventional formulations. Ceresin wax was employed to improve permeability, oral bioavailability and patient compliance by preparing enalapril (EP)-loaded lipospheres with a simple solvent evaporation method. A Box–Behnken design with the proposed polynomial equations and quadratic model was applied to investigate and statistically validate the collective influence of formulation variables on lipospheres. Spherical smooth-surfaced lipospheres with an average size of 55 μm with excellent micromeritic properties were produced. Differential scanning calorimetry, X-ray diffraction and Fourier transmission infrared spectroscopy findings proved the lack of any possible interaction between formulation components. The zeta potential ranged from −5 to −20 mV, suggesting the significant stability of lipospheres. Responses such as percentage yield (29–68%), entrapment efficiency (21–53%) and drug release (42–93%) were found to be affected greatly by the concentrations of lipids and the surfactant, and the stirring speed. Reduced and sustained EP release from lipospheres may lower treatment cost and enhance hypertensive patients’ compliance.

Evaluation of the Properties of Encapsulated Stavudine Microparticulate Lipid-based Drug Delivery System in Immunocompromised Wistar Rats

BACKGROUND

Lipid-based formulations have been confirmed to lower some side effects of drugs and can be tailor-made to offer sustained drug release of drugs with short half-life like stavudine.

AIM

This study aimed to evaluate the immunomodulatory properties of stavudine-loaded solid lipid microparticles (SLMs) using immunocompromised Wistar rats.

METHODS

The SLMs were formulated by the homogenization method. The optimized batches were used for further in vivo studies. The effect of formulation on the CD4 count and the haematological properties of immunocompromised Wistar rats were studied.

RESULTS

The particle size range was 4 -8 μm, EE range was 85-93 % and maximum drug release was observed at 10 h. The CD4 cells increased from 115 ± 3.17 cell/mm3 at day zero to 495 ± 5.64 cell/mm3 at day 14 of treatment and 538 ± 6.31 cell/mm3 at day 21. The red blood cells increased from 2.64 ± 1.58 (x 106/mm3) at day zero to 6.96 ± 3.47 (x 106/mm3) at day 14 and 7.85 ± 3.64 (x 106/mm3) at day 21. PCV increased significantly (p < 0.05) to about 42-50 % at day 21 in the groups that received the SLMs formulations. White blood cells (WBC) also were 12 x 103/mm3, for SLM formulations, while the rats that received plain stavudine exhibited WBC of 9.6 x 103/mm3 at day 21. The histopathological studies revealed that oral stavudine-loaded SLMs had no significant damage to the kidney, liver, spleen and the brain of Wistar rats.

CONCLUSION

The formulations exhibited significantly higher immunomodulatory properties than plain stavudine (p<0.05) and showed good properties for once daily oral administration and could be a better alternative to plain stavudine tablets for the management of patients living with HIV.

Anti-Inflammatory and Gastroprotective Properties of Aspirin - Entrapped Solid Lipid Microparticles

Background: Aspirin is a nonsteroidal anti-inflammatory drug that is very effective in the treatment of inflammation and other health conditions, however, it causes gastric irritation. Recently, researchers have developed patents (US9757529, 2019) of inhalable aspirin for rapid absorption and circumvention of gastric irritation.

Objective: The aim of this work was to formulate aspirin-loaded lipid based formulation in order to enhance oral bioavailability and inhibit gastric irritation.

Methods: This solid lipid microparticles loaded with aspirin (SLM) was formulated by a modified cold homogenization-solvent evaporation method. In vitro studies such as in vitro drug release, particle size, Encapsulation Efficiency (EE), micromeritic properties and loading capacity were carried out. Pharmacodynamics studies such as anti-inflammatory and ulcerative properties of the SLM were also carried out in Wistar rats.

Results: The results showed that aspirin entrapped SLM exhibited the highest EE of 72% and particle size range of 7.60 + 0.141µm to 20.25 + 0.070µm. Formulations had about 55% drug release at 6h in simulated intestinal fluid pH 6.8.The formulations had good flowability that could facilitate filling into hard gelatin capsule shells. The SLM exhibited 100% gastroprotection against aspirin-induced ulcers (p < 0.05). The percentage of anti-inflammatory activities also showed that aspirin-entrapped SLM had 78% oedema inhibition at 7h, while the reference had 68% inhibition at 7h.

Conclusion: Aspirin-entrapped SLM showed good sustained-release properties, enhanced anti-inflammatory properties and total gastric protection from aspirin-induced ulcers and could be used as once-daily oral aspirin.

Application of SRMS 154 as Sustained Release Matrix for the Delivery of Stavudine: In vitro and in vivo Evaluation and Effect of Poloxamer 188 on the Properties of the Tablets

BACKGROUND

Stavudine is an antiretroviral therapy with so many side effects and has a short half-life of 1.5 h. It degrades to thymine under hydrolytic, oxidative and photolytic conditions hence has major formulation challenges.

OBJECTIVES

To formulate sustained release lipid based stavudine and to study the properties of the formulations by in vitro and in vivo methods.

METHODS

Stavudine tablets were formulated by moulding using validated tablets moulds. The carrier used were solidified reverse micellar solution (SRMS) made up of varying ratios of hydrogenated palm oil and Phospholipid admixtures. Evaluation tests were carried out on the tablets using both Pharmacopoeial and non Pharmacopoeial test. Drug release was studied in both simulated gastric fluid (SGF, pH 1.2) and simulated intestinal fluid (SIF, pH 7.2). In vivo release was studied using Wistar rats.

RESULTS

The results showed that stavudine tablets exhibited weight range of 372 ± 0.14 to 386 ± 0.52 mg, friability ranged from 0.00 to 0.13 % and hardness ranged from 4.27 ± 0.25 to 5.30 ± 0.21 Kgf. Tablets formulated with SRMS 1:2 had erosion time range of 60.80 ± 1.23 to 87.90 ± 2.33 min and was affected significantly by the presence of Poloxamer 188 (p < 0.05). The formulations exhibited T100 % at 10 to13 h in SIF. Stavudine tablets showed the area under the curve (AUC) of 854.0 μg/h/ml, significantly higher than the AUC of the reference (p < 0.05).

CONCLUSION

Stavudine SRMS-based tablets had good stability and sustained release properties. Formulations containing 1 % Poloxamer 188 exhibited enhanced in vivo absorption and hence could be used once daily in order to enhance the bioavailability of this drug.

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.

Investigation of novel solid lipid microparticles based on homolipids from Bos indicus for the delivery of gentamicin

Background:

The aim of this study was to formulate solidified reverse micellar solution (SRMS)-based solid lipid microparticles (SLMs) using homolipids from tallow fat (Bos indicus) and evaluate its potential for enhanced delivery of gentamicin.

Materials and Methods:

SLMs were formulated by melt-emulsification using SRMS (15% w/w Phospholipon^® 90G in 35% w/w Bos indicus), polyethylene glycol 4000 (PEG) and gentamicin (1.0, 2.0, 3.0% w/w), and characterized with respect to size, morphology, encapsulation efficiency % and pH-dependent stability. The in vitro release of gentamicin from the SLMs was performed in phosphate buffer (pH 7.4) while bioevaluation was carried out using clinical isolates of Staphylococcus aureus and Escherichia coli.

Results:

Results showed that the lipid matrix accommodated gentamicin in a concentration-dependent manner, and that stable and spherical SLMs with size range of 18.62 ± 1.24-20.59 ± 1.36 μm and 21.35 ± 1.57-50.62 ± 2.37 μm respectively for unloaded and drug-loaded formulations were obtained. The in vitro drug release studies revealed that SRMS-based SLMs could better be used to control the release of gentamicin than gentamicin injection. Results of sensitivity test revealed that the SLMs time-dependently and capacity-limitedly produced greater inhibition zone diameters (IZDs) than the standards, an indication of improved bioactivity against the test organisms, with greater IZDs against S. aureus than E. coli. Overall, SLMs containing 2% w/w SRMS, 3% w/w gentamicin and PEG 4000 entrapped the highest amount of drug, achieved complete drug release and gave highest IZD against the organisms within 420 min, while plain gentamicin gave the least.

Conclusion:

This research has shown that SLMs based on Bos indicus and P90G is a potential carrier system for dissolution and bioactivity enhancement of gentamicin.

Evaluation of dika wax-soybean oil-based artesunate-loaded lipospheres: in vitro-in vivo correlation studies

OBJECTIVES

To formulate and evaluate artesunate-loaded lipospheres and study the in vitro-in vivo correlations (IV-IVC).

MATERIALS AND METHODS

Lipospheres were formulated by melt homogenisation using structured lipid matrices consisting of (1:3 and 1:6) soybean oil and dika wax and were characterised in vitro and in vivo.

RESULTS

The small angle X-ray diffraction (SAXD) results of the lipid matrices showed prominent reflection at 2θ = 2.49°, d = 3.55 Å while, wide angle X-ray diffraction (WAXD) showed prominent reflection at 2θ = 20.83°, d = 0.42 Å. Lipospheres had maximum encapsulation efficiency of 80%, showed no significant decrease in pH with time (p < 0.05), and had sustained release properties. The ratio of the area under the curve (AUC) of the lipospheres and the tablets gave bioavailability enhancement factor of 2.108.

CONCLUSION

Artesunate-loaded lipospheres could be used orally or parenterally once daily, for the treatment of malaria.

Formulation of novel sustained release rifampicin-loaded solid lipid microparticles based on structured lipid matrices from Moringa oleifera

OBJECTIVES

To formulate sustained release rifampicin-loaded solid lipid microparticles (SLMs) using structured lipid matrices based on Moringa oil (MO) and Phospholipon 90G (P90G).

METHODS

Rifampicin-loaded and unloaded SLMs were formulated by melt homogenization and characterized in terms of particle morphology and size, percentage drug content (PDC), pH stability, stability in simulated gastric fluid (SGF, pH 1.2), minimum inhibitory concentration (MIC) and in vitro release. In vivo release was studied in Wistar rats.

RESULTS

Rifampicin-loaded SLMs had particle size range of 32.50 ± 2.10 to 34.0 ± 8.40 μm, highest PDC of 87.6% and showed stable pH. SLMs had good sustained release properties with about 77.1% release at 12 h in phosphate buffer (pH 6.8) and 80.3% drug release at 12 h in simulated intestinal fluid (SIF, pH 7.4). SLMs exhibited 48.51% degradation of rifampicin in SGF at 3 h, while rifampicin pure sample had 95.5% degradation. Formulations exhibited MIC range of 0.781 to 1.562, 31.25 to 62.5 and 6.25 to 12.5 μg/ml against Salmonella typhi, Escherichia coli, and Bacillus subtilis respectively and had higher in vivo absorption than the reference rifampicin (p < 0.05).

CONCLUSION

Rifampicin-loaded SLMs could be used once daily for the treatment tuberculosis.

Formulation in vitro and in vivo evaluation of SRMS-based heterolipid-templated homolipid delivery system for diclofenac sodium

The sole objective of this work was to design successful dosage oral forms of diclofenac sodium (DiNa)-loaded solid lipid microparticles (SLM) based on solidified reverse micellar solution (SRMS). Hot homogenization technique was employed to prepare DicNa SLM using a mixture goat fat and Phospholipon® 90 G as lipid matrix and Tween®-80 as mobile surfactant. Characterization based on percentage yield, morphology, particle size, zeta potential, percentage encapsulation, pH and stability of SLMs were investigated. Anti-inflammatory, gastrointestinal tract (GIT) sparing effect and pharmacokinetics were carried out in rat model after oral administration. Results showed that the SLMs were spherical and smooth. The optimized formulation (SLM-4) had particle size of 79.40 ± 0.31 µm, polydispersity index of 0.633 ± 0.190, zeta potential of -63.20 ± 0.12 mV and encapsulation efficiency of 91.2 ± 0.1% with good stability after 8 months of storage. The DicNa SLM had sustained release effect with good anti-inflammatory activity. Higher and prolonged plasma DicNa concentration was shown by the SLM-4 compared to pure drug and a conventional sample. These studies demonstrate that DicNa-loaded SLM based on SRMS could be a promising oral formulation for enhanced bioavailability, pharmacologic activity and gastrointestinal sparing effect of the NSAID, DicNa.

Effects of the sol-gel route on the structural characteristics and antibacterial activity of silica-encapsulated gentamicin

The effects of sol-gel processes, i.e., acid-catalyzed gelation, base-catalyzed gelation and base-catalyzed precipitation routes, on the encapsulation of gentamicin were investigated. The resulting xerogels were characterized using a series of complementary instrumental techniques, i.e., the adsorption/desorption of nitrogen, small-angle X-ray scattering, Fourier transform infrared spectroscopy, diffuse reflectance spectroscopy, X-ray photoelectron spectroscopy, atomic force microscopy and scanning electron microscopy. The encapsulated gentamicin samples were tested against a series of Gram-positive and Gram-negative bacterial strains. The best antimicrobial activity was observed with the encapsulated gentamicin that was prepared via the precipitation route, even in comparison with the neat antibiotic, especially in the case of the Gram-positive strain Staphylococcus aureus. The gentamicin concentration on the outermost surface and the zeta potential were identified as factors that affected the highest efficiency, as observed in the case of encapsulation via the base-catalyzed process.

Formulation development and evaluation of the anti-malaria properties of sustained release artesunate-loaded solid lipid microparticles based on phytolipids

CONTEXTS: Artemisinins and its derivatives are considered the basis in the treatment of Plasmodium falciparum malaria due to their high potency and rapid action. However, they have short half life, low solubility, and poor oral bioavailability, hence the need to formulate sustained release lipid particulate dosage form of these drugs.

OBJECTIVES

To formulate and evaluate artesunate-loaded solid lipid microparticles (SLMs) based on structured lipid matrices consisting of soybean oil and dika wax.

MATERIALS AND METHODS

The lipid matrices were characterized by differential scanning calorimetry (DSC), small-angle X-ray diffraction (SAXD), and wide-angle X-ray diffraction (WAXD). The SLMs were prepared by hot melt-homogenization. Time-dependent particle size analysis, time-dependent pH stability studies, encapsulation efficiency (EE%), and in vitro drug release were carried out on the SLMs. In vivo anti-malarial studies were performed using a modified Peter's 4-day suppressive protocol using Plasmodium berghei infected mice.

RESULTS AND DISCUSSION

Thermograms of the lipid matrices showed modifications in the microstructure of dika wax as a result of inclusion of soybean oil. SAXD and WAXD diffractograms showed that the lipid matrices were found to be non-lamellar. Particle size of SLM increased with time, while the pH was almost constant. The SLMs had maximum EE% of 80.6% and sustained the release of artesunate more than the reference tablet. In vivo pharmacodynamic studies showed that the SLMs had significant (p < 0.05) reduction in parasitaemia compared with reference tablet.

CONCLUSION

Artesunate-loaded SLMs could be used once daily in the treatment of malaria.

Analgesic and Micromeritic evaluations of SRMS-based oral Lipospheres of Diclofenac Potassium

The objective of our work was to study the micromeritic properties of lyophilized diclofenac potassium-loaded lipospheres and to evaluate in vivo, the analgesic properties of diclofenac potassium in the lipospheres in addition to other in vitro properties. Solidified reverse micellar solutions were prepared by fusion using 1:1, 2:1, and 1:2% w/w of Phospholipon(®) 90H and Softisan(®) 154. Diclofenac potassium (1, 3, and 5% w/w) was incorporated into the solidified reverse micellar solutions. Solidified reverse micellar solutions-based lipospheres were formulated by melt homogenization techniques using Ultra-Turrax homogenizer, and thereafter lyophilized to obtain water-free lipospheres. The lipospheres were characterized in terms of particle size and morphology, stability, thermal analysis, drug content, encapsulation efficiency, and loading capacity. The flow properties of the lipospheres were studied using both direct and indirect methods of assessing flow. The analgesic properties of the lipospheres were studied using the hot plate method. Results obtained showed that the yield of diclofenac potassium-loaded lipospheres was high and the particle size ranged from 0.61±0.07 to 2.55±0.04 μm. The lipospheres had high encapsulation efficiency of 95%, which was affected by the amount of drug loaded, while the loading capacity increased with the increase in drug loading. Diclofenac potassium-loaded lipospheres exhibited poor flow. The formulations exhibited good analgesic effect compared with the reference and had 84 to 86% drug release at 13 h. The lipospheres based on solidified reverse micellar solutions could be used for oral delivery of diclofenac potassium.