Preparation and characterization of ibuprofen microspheres

Evaluation of Emulgel and Nanostructured Lipid Carrier-Based Gel Formulations for Transdermal Administration of Ibuprofen: Characterization, Mechanical Properties, and Ex-Vivo Skin Permeation

In transdermal applications of nonsteroidal anti-inflammatory drugs, the rheological and mechanical properties of the dosage form affect the performance of the drug. The aim of this study to develop emulgel and nanostructured lipid carrier NLC-based gel formulations containing ibuprofen, evaluate their mechanical properties, bioadhesive value and ex-vivo rabbit skin permeability. All formulations showed non-Newtonian pseudoplastic behavior and their viscosity values are suitable for topical application. The particle size of the nanostructured lipid carrier system was found to be 468 ± 21 nm, and the encapsulation efficiency was 95.58 ± 0.41%. According to the index of viscosity, consistency, firmness, and cohesiveness values obtained as a result of the back extrusion study, E2 formulation was found to be more suitable for transdermal application. The firmness and work of shear values of the E2 formulation, which has the highest viscosity value, were also found to be the highest and it was chosen as the most suitable formulation in terms of the spreadability test. The work of bioadhesion values of NLC-based gel and IBU-loaded NLC-based gel were found as 0.226 ± 0.028 and 0.181 ± 0.006 mJ/cm2 respectively. The percentages of IBU that penetrated through rabbit skin from the Ibuactive-Cream and the E2 were 87.4 ± 2.11% and 93.4 ± 2.72% after 24 h, respectively. When the penetration of ibuprofen through the skin was evaluated, it was found that the E2 formulation increased penetration due to its lipid and nanoparticle structure. As a result of these findings, it can be said that the NLC-based gel formulation will increase the therapeutic efficacy and will be a good alternative transdermal formulation.

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.

Validation and scalability of homemade polycaprolactone macro-beads grafted with thermo-responsive poly (N-isopropyl acrylamide) for mesenchymal stem cell expansion and harvesting

In this study, polycaprolactone (PCL) macro-beads were prepared by an oil-in-water (o/w) emulsion solvent evaporation method with poly (vinyl alcohol) (PVA) as an emulsifier and conjugated to poly (N-isopropyl acrylamide) (PNIPAAm) to be used as cell carriers with non-invasive cell detachment properties (thermo-response). Following previous studies with PCL-PNIPAAm carriers, our objectives were to confirm the successful conjugation on homemade macro-beads and to show the advantages of homemade production over commercial beads to control morphological, biological and fluidization properties. The effects of PCL concentration on the droplet formation and of flow rate and PVA concentration on the size of the beads were demonstrated. The size of the beads, all spherical, ranged from 0.5 mm to 3.7 mm with four bead categories based on production parameters. The morphology and size of the beads were observed by scanning electron microscopy to show surface roughness enhancing cell attachment and proliferation compared to commercial beads. The functionalization steps with PNIPAAm were then characterized and confirmed by Fourier transform infrared spectroscopy (FTIR), SEM and Energy Dispersion Spectroscopy (EDS). PNIPAAm-grafted macro-beads allowed mesenchymal stem cells (MSC) to spread and grow for up to 21 days. By reducing the temperature to 25 °C, the MSCs were successfully detached from the PCL-PNIPAAm beads as observed with fluorescence microscopy. Furthermore, we validated the scalability potential of both macro-beads production and conjugation with PCL, in order to produce easily kilograms of thermo-responsive macro-carriers in a lab environment. This could help moving such approaches towards clinically and industrially relevant processes were cell expansion is needed at very large scale. This article is protected by copyright. All rights reserved.

Controlled Delivery of Pan-PAD-Inhibitor Cl-Amidine Using Poly(3-Hydroxybutyrate) Microspheres

This study deals with the process of optimization and synthesis of Poly(3-hydroxybutyrate) microspheres with encapsulated Cl-amidine. Cl-amidine is an inhibitor of peptidylarginine deiminases (PADs), a group of calcium-dependent enzymes, which play critical roles in a number of pathologies, including autoimmune and neurodegenerative diseases, as well as cancer. While Cl-amidine application has been assessed in a number of in vitro and in vivo models; methods of controlled release delivery remain to be investigated. P(3HB) microspheres have proven to be an effective delivery system for several compounds applied in antimicrobial, wound healing, cancer, and cardiovascular and regenerative disease models. In the current study, P(3HB) microspheres with encapsulated Cl-amidine were produced in a size ranging from ~4–5 µm and characterized for surface morphology, porosity, hydrophobicity and protein adsorption, in comparison with empty P(3HB) microspheres. Cl-amidine encapsulation in P(3HB) microspheres was optimized, and these were found to be less hydrophobic, compared with the empty microspheres, and subsequently adsorbed a lower amount of protein on their surface. The release kinetics of Cl-amidine from the microspheres were assessed in vitro and expressed as a function of encapsulation efficiency. There was a burst release of ~50% Cl-amidine in the first 24 h and a zero order release from that point up to 16 days, at which time point ~93% of the drug had been released. As Cl-amidine has been associated with anti-cancer effects, the Cl-amidine encapsulated microspheres were assessed for the inhibition of vascular endothelial growth factor (VEGF) expression in the mammalian breast cancer cell line SK-BR-3, including in the presence of the anti-proliferative drug rapamycin. The cytotoxicity of the combinatorial effect of rapamycin with Cl-amidine encapsulated P(3HB) microspheres was found to be 3.5% more effective within a 24 h period. The cells treated with Cl-amidine encapsulated microspheres alone, were found to have 36.5% reduction in VEGF expression when compared with untreated SK-BR-3 cells. This indicates that controlled release of Cl-amidine from P(3HB) microspheres may be effective in anti-cancer treatment, including in synergy with chemotherapeutic agents. Using controlled drug-delivery of Cl-amidine encapsulated in Poly(3-hydroxybutyrate) microspheres may be a promising novel strategy for application in PAD-associated pathologies.

Design and In Vitro Evaluation of Eudragit-Based Extended Release Diltiazem Microspheres for Once- and Twice-Daily Administration: The Effect of Coating on Drug Release Behavior

Objectives

The aim of this investigation was to develop an extended release formulation of diltiazem hydrochloride (DL) for once- and twice-daily administration, based on Eudragit (Eud) RL and RS microspheres using emulsion solvent evaporation.

Materials and Methods

Formulations with different drug-polymer concentrations were produced and characterized in terms of yield, encapsulation efficiency (EE), particle size, and surface morphology. The drug release and thermal behavior of the microspheres were also investigated. Selected microspheres were then coated with Eud RS by continuous solvent evaporation, in order to modify the microspheres' properties and burst release.

Results

According to the results, the EE was in the range of 56%-93% for uncoated microspheres. The mean particle size of microspheres was different from 470 to above 1000 μm, based on various formulation variables. No difference was observed between the mean size of particles prepared with Eud RL and Eud RS. Microspheres showed sustained release behavior, which was affected by the drug:polymer ratio as well as particle size. Coating the microspheres not only improved the EE values (82%-92%) but also reduced the mean dissolution rate as well as the burst release.

Conclusion

Microspheres prepared with DL:Eud RL ratios of 1:3 and 1:4 showed release profiles in accordance with the USP criteria for a DL extended release product for dosing every 12 and 24 h, respectively.

SPHRINT - Printing Drug Delivery Microspheres from Polymeric Melts

This paper describes a simple, straightforward, and rapid method for producing microspheres from molten polymers by merely printing them in an inkjet-like manner onto a superoleophobic surface (microsphere printing, hence SPHRINT). Similar to 3D printing, a polymer melt is deposited onto a surface; however, in contrast to 2D or 3D printing, the surface is not wetted (i.e. exhibiting high contact angles with liquids, above 150°, due to its low surface energy), resulting in the formation of discrete spherical microspheres. In this study, microspheres were printed using polycaprolactone and poly(lactic-co-glycolic acid) loaded with a model active pharmaceutical ingredient-ibuprofen (IBU). The formation of microspheres was captured by high-speed imaging and was found to involve several physical phenomena characterized by non-dimensional numbers, including the thinning and breakup of highly viscous, weakly elastic filaments, which are first to be described in pure polymer melts. The resulting IBU-loaded microspheres had higher sphericity, reproducible sizes and shapes, and superior drug encapsulation efficiencies with a distinctly high process yield (>95%) as compared to the conservative solvent-based methods used presently. Furthermore, the microspheres showed sustained release profiles.

Improving the skin penetration and antifebrile activity of ibuprofen by preparing nanoparticles using emulsion solvent evaporation method

Ibuprofen (IBU) is an effective analgesic, non-steroidal anti-inflammatory drug. Unfortunately, oral IBU can cause adverse gastrointestinal drug reactions, such as bleeding and ulcerations, and increases the risk for stomach or intestinal perforations. In this study, IBU nanoparticles (IBU-NPs) were prepared through emulsion solvent evaporation and freeze-drying to improve their solubility. IBU nanoemulsion and nanosuspension were optimized through a single-factor experiment. IBU-NPs with a mean particle size of 216.9±10.7nm were produced under optimum conditions. These IBU-NPs were characterized by using scanning electron microscopy, X-ray diffraction, differential scanning calorimetry, and residual solvent determination to determine their solvent residue, equilibrium solubility, dissolution rate, in vitro transdermal rate, transdermal bioavailability, and antifebrile experiment for febrile rats. The morphological characteristic of IBU-NPs showed porous clusters. Analysis results indicated that the prepared IBU-NPs have low crystallinity. Residual amounts of ethanol and chloroform were 170 and 9.6ppm, respectively, which were less than the ICH limit for class II. Measurement analysis showed that the IBU-NPs were converted underwent amorphous states after preparation, but the chemical structure of the IBU-NPs was unchanged. Transdermal bioavailability of IBU in the IBU-NP group improved significantly compared with oral and transdermal raw IBU. Furthermore, the IBU-NP transdermal gel exhibited a high and stable cooling rate and a long cooling duration in febrile rats. In comparison with the raw oral IBU and raw IBU transdermal gel, the IBU-NP transdermal gel manifested better efficacy at low and mid doses. Basing from the results, we conclude that IBU-NPs can be applied in transdermal delivery formulations and have potential application value for non-oral administration.

Design, characterization and in vitro evaluation of HPMC K100 M CR loaded Fexofenadine HCl microspheres

The aim of the current study was to formulate Fexofenadine hydrochloride loaded sustained release microspheres using HPMC K100 M CR, a release retardant hydrophilic polymer by solvent evaporation method. The effect of different drug loading on drug content, drug encapsulation efficiency and release of drug was monitored. The studies on in vitro release mechanism were performed using USP paddle method with 900 ml of phosphate buffer (pH 6.8) for 10 h at 100 rpm. The mechanism of the drug release was determined by fitting in vitro release data to various release kinetic models such as the zero order, first order, Higuchi, Hixson Crowell and Korsemeyer–Peppas model and finding R² values for the release profile corresponding to each model. The results confirm that the release rate of the drug from the microspheres is highly affected by the drug to polymer ratio. The study finds that Higuchi release kinetics, Korsmeyer–Peppas release kinetics and Hixson–Crowell release kinetics were the major release mechanism. The release mechanism was found to be non-Fickian with increase of polymer content. Scanning electron microscopic technique was performed to obtain the morphological changes due to different drug loading. Differential scanning calorimetry and Fourier transform infra-red spectroscopy was performed to determine any interaction of drug with the polymer. A statistically significant variation in release rate was observed for variation in the amount of HPMC K100 M CR. In the present study, a series of sustained release formulations of Fexofenadine hydrochloride were developed with different drug loading so that these formulations could further be evaluated from the in vivo studies. The formulations were found to be stable and reproducible.

Formulation and evaluation of controlled-release of telmisartan microspheres: In vitro/in vivo study

The aim of this work was to design a controlled-release drug-delivery system for the angiotensin-II receptor antagonist drug telmisartan. Telmisartan was encapsulated with different EUDRAGIT polymers by an emulsion solvent evaporation technique and the physicochemical properties of the formulations were characterized. Using a solvent evaporation method, white spherical microspheres with particle sizes of 629.9–792.1 μm were produced. The in vitro drug release was studied in three different pH media (pH 1.2 for 2 hours, pH 6.8 for 4 hours, and pH 7.4 for 18 hours). The formulations were then evaluated for their pharmacokinetic parameters. The entrapment efficiency of these microspheres was between 58.6% and 90.56%. The obtained microspheres showed good flow properties, which were evaluated in terms of angle of repose (15.29–26.32), bulk and tapped densities (0.37–0.53 and 0.43–0.64, respectively), Carr indices and Hausner ratio (12.94–19.14% and 1.14–1.23, respectively). No drug release was observed in the simulated gastric medium up to 2 hours; however, a change in pH from 1.2 to 6.8 increased the drug release. At pH 7.4, formulations with EUDRAGIT RS 100 showed a steady drug release. The microsphere formulation TMRS-3 (i.e., microspheres containing 2-mg telmisartan) gave the highest C_max value (6.8641 μg/mL) at 6 hours, which was three times higher than C_max for telmisartan oral suspension (TOS). Correspondingly, the area under the curve for TMRS-3 was 8.5 times higher than TOS. Particle size and drug release depended on the nature and content of polymer used. The drug release mechanism of the TMRS-3 formulation can be explained using the Higuchi model. The controlled release of drug from TMRS-3 also provides for higher plasma drug content and improved bioavailability.

PVA-based hybrid composites with luminescent properties for drug delivery

The aim of this study was to synthesize and characterize new poly(vinyl alcohol)s (PVAs) hybrid composites with or without a basic drug content, e.g., 2-[4-(2-methylpropyl)phenyl]propanoic acid (ibuprofen), obtained at different pH values. Through sol-gel approach of chloropropyltriethoxysilane with a PVA precursor containing a fluorescent dye (lissamine rhodamine-B sulfonyl chloride), new hybrid materials with porous structures were obtained. Due to encapsulation in a porous network, the influence of rhodamine H-dimers on fluorescence quenching was negligible and the presence of free dye was exploited as a mechanism for anchoring the ibuprofen molecules through hydrogen bonding onto pore surfaces.

Multiunit floating drug delivery system of rosiglitazone maleate: development, characterization, statistical optimization of drug release and in vivo evaluation

A multiunit floating drug delivery system of rosiglitazone maleate has been developed by encapsulating the drug into Eudragit RS100 through nonaqueous emulsification/solvent evaporation method. The in vitro performances of microspheres were evaluated by yield (%), particle size analysis, drug entrapment efficiency, in vitro floating behavior, surface topography, drug-polymer compatibility, crystallinity of the drug in the microspheres, and drug release studies. In vitro release was optimized by a {3, 3} simplex lattice mixture design to achieve predetermined target release. The in vivo performance of the optimized formulation was evaluated in streptozotocin-induced diabetic rats. The results showed that floating microspheres could be successfully prepared with good yields (69-75%), high entrapment (78-97%), narrow size distribution, and desired target release with the help of statistical design of experiments from very small number of formulations. In vivo evaluation in albino rats suggested that floating microspheres of rosiglitazone could be a promising approach for better glycemic control.

Design and development of gliclazide mucoadhesive microcapsules: in vitro and in vivo evaluation

In this study an attempt was made to prepare mucoadhesive microcapsules of gliclazide using various mucoadhesive polymers designed for oral controlled release. Gliclazide microcapsules were prepared using sodium alginate and mucoadhesive polymer such as sodium carboxymethyl cellulose (sodium CMC), carbopol 934P or hydroxy propylmethyl cellulose (HPMC) by orifice-ionic gelation method. The microcapsules were evaluated for surface morphology and particle shape by scanning electron microscope. Microcapsules were also evaluated for their microencapsulation efficiency, in vitro wash-off mucoadhesion test, in vitro drug release and in vivo study. The microcapsules were discrete, spherical and free flowing. The microencapsulation efficiency was in the range of 65-80% and microcapsules exhibited good mucoadhesive property in the in vitro wash off test. The percentage of microcapsules adhering to tissue at pH 7.4 after 6 h varied from 12-32%, whereas the percentage of microcapsules adhering to tissue at pH 1.2 after 6 h varied from 35-68%. The drug release was also found to be slow and extended for more than 16 h. In vivo testing of the mucoadhesive microcapsules in diabetic albino rats demonstrated significant antidiabetic effect of gliclazide. The hypoglycemic effect obtained by mucoadhesive microcapsules was for more than 16 h whereas gliclazide produced an antidiabetic effect for only 10 h suggesting that mucoadhesive microcapsules are a valuable system for the long term delivery of gliclazide.