Ketoprofen-loaded Eudragit RSPO microspheres: An influence of sodium carbonate onin vitrodrug release and surface topology

Coprecipitation of Class II NSAIDs with Polymers for Oral Delivery

Non-steroidal anti-inflammatory drugs (NSAIDs) are frequently administered orally with modified-release formulations. The attainment of modified-release drugs is commonly achieved through the coprecipitation of the active principle with a biodegradable polymeric carrier in the form of micro or nanoparticles. In this review, some coprecipitation studies of three highly prescribed NSAIDs (in particular, ibuprofen, ketoprofen, and diclofenac sodium) have been analyzed. The techniques employed to micronize the powder, the polymers used, and the main results have been classified according to the type of release required in different categories, such as delayed, immediate, prolonged, sustained, and targeted release formulations. Indeed, depending on the pathology to be treated, it is possible to achieve specific therapeutic objectives, ensuring that the drug is released at a higher or lower dissolution rate (if compared to conventional drugs) and/or at a different time and/or in a specific site of action.

A Novel Prototype Device for Microencapsulation of Benznidazole: In Vitro/In Vivo Studies

This study was aimed to design a simple and novel prototype device for the production of polymeric microparticles. To prove the effectiveness of this device, benznidazole microparticles using chitosan as carrier and NaOH, KOH, or SLS as counter ions were used. For comparison, benznidazole microparticles were prepared by the conventional dripping technique (syringe and gauge) using the same excipients. Microparticles were characterized in terms of encapsulation efficiency, particle shape, size and surface topography, crystallinity characteristics, thermal behavior, and dissolution rate. Then, the pharmacokinetic parameters were evaluated after the oral administration of the microparticles to healthy Wistar rats. The prepared formulations, by means of this device, showed good drug encapsulation efficiency (> 70%). Release studies revealed an increased dissolution of benznidazole from chitosan microparticles prepared using the novel device. It achieved more than 90% in 60 min, while those of the conventional microparticles and raw drug achieved 65% and 68%, respectively, during the same period. Almost spherical benznidazole microparticles with a smooth surface and size around 10-30 μm were observed using scanning electron microscopy. Thermal analysis and X-ray diffraction studies suggested a partial reduction of drug crystallinity. Moreover, the relative oral bioavailability of the novel benznidazole microparticles showed that the area under the curve for the microencapsulated drug was 10.3 times higher than the raw drug. Thus, these findings indicate that the designed glass prototype device is a useful alternative to formulate benznidazole polymeric microparticles with improved biopharmaceutical properties and could be useful for other therapeutic microparticulate systems.

Maximizing the encapsulation efficiency and the bioavailability of controlled-release cetirizine microspheres using Draper-Lin small composite design

This study was aimed at developing a controlled-release cetirizine hydrochloride (CTZ)-loaded polymethacrylate microsphere by optimization technique using software-based response surface methodology. The emulsion solvent evaporation method was utilized in the preparation of microspheres. Four process variables were selected, namely, Eudragit RLPO loading percentage in total polymer, the emulsifier hydrophilic lipophilic balance (HLB), the antitacking percentage, and the dispersed phase volume. The desired responses were particle size, angle of repose, production yield, encapsulation efficiency, loading capacity, initial drug release, and the time for 85% of drug release from the microspheres. Optimization was carried out by fitting the experimental data to the software program (Statgraphics Centurion XV). Moreover, 18 batches were subjected to various characterization tests required for the production of dosage form. The pharmacokinetic parameters were evaluated after the oral administration of 10 mg CTZ in both optimized formulation and commercial product on healthy human volunteers using a double-blind, randomized, cross-over design. The optimized formulation showed satisfactory yield (84.43%) and drug encapsulation efficiency (87.1%). Microspheres were of spherical shape, smooth surface, and good flowability with an average size of 142.3 μm. The developed optimized batch of microspheres ensured 28.87% initial release after 2 hours, and the release of CTZ extended for >12 hours. In addition, the relative bioavailability of the optimized formulation was 165.5% with respect to the marketed CTZ tablets indicating a significant enhancement of CTZ bioavailability. Thus, there is an expectation to decrease the administered dose and the frequency of administration, and subsequently minimize the adverse effects that are faced by the patient during the treatment.

Influence of some formulation variables on the optimization of pH-dependent, colon-targeted, sustained-release mesalamine microspheres

The aim of this work was to understand the influence of different formulation variables on the optimization of pH-dependent, colon-targeted, sustained-release mesalamine microspheres prepared by O/O emulsion solvent evaporation method, employing pH-dependent Eudragit S and hydrophobic pH-independent ethylcellulose polymers. Formulation variables studied included concentration of Eudragit S in the internal phase and the ratios between; internal to external phase, drug to Eudragit S and Eudragit S to ethylcellulose to mesalamine. Prepared microspheres were evaluated by carrying out in vitro release studies and determination of particle size, production yield, and encapsulation efficiency. In addition, morphology of microspheres was examined using optical and scanning electron microscopy. Emulsion solvent evaporation method was found to be sensitive to the studied formulation variables. Particle size and encapsulation efficiency increased by increasing Eudragit S concentration in the internal phase, ratio of internal to external phase, and ratio of Eudragit S to the drug. Employing Eudragit S alone in preparation of the microspheres is only successful in forming acid-resistant microspheres with pulsatile release pattern at high pH. Eudragit S and ethylcellulose blend microspheres were able to control release under acidic condition and to extend drug release at high pH. The stability studies carried out at 40°C/75% RH for 6 months proved the stability of the optimized formulation. From the results of this investigation, microencapsulation of mesalamine in microspheres using blend of Eudragit S and ethylcellulose could constitute a promising approach for site-specific and controlled delivery of drug in colon.

Preparation and characterization of metformin hydrochloride loaded-Eudragit®RSPO and Eudragit®RSPO/PLGA nanoparticles

The aim of the present study was to develop and characterize metformin HCl-loaded nanoparticle formulations. Nanoparticles were prepared by the nanoprecipitation method using both a single polymer (Eudragit(®)RSPO) and a polymer mixture (Eudragit/PLGA). The mean particle size ranged from 268.8 to 288 nm and the nanoparticle surface was positively charged (9.72 to 10.1 mV). The highest encapsulation efficiency was observed when Eudragit®RSPO was used. All formulations showed highly reproducible drug release profiles and the in vitro drug release in phosphate buffer (pH = 6.8) ranged from 92 to 100% in 12 h. These results suggest that Eudragit(®)RSPO or Eudragit/PLGA nanoparticles might represent a promising sustained-release oral formulation for metformin HCl, reducing the necessity of repeated administrations of high doses to maintain effective plasma concentrations, and thus, increasing patient compliance and reducing the incidence of side-effects.