This study examines the controlled release behavior of both water-soluble (acetaminophen, caffeine, theophylline and salicylic acid) and water insoluble (indomethacin) drugs derived from Caesalpinia pulcherrima seed Gum isolated from Caesalpinia pulcherrima kernel powder. It further investigates the effect of incorporating diluents such as microcrystalline cellulose and lactose on caffeine release. In addition the effect the gum’s (polysaccharide) partial cross-linking had on release of acetaminophen was examined. Applying the exponential equation, the soluble drugs mechanism of release was found to be anomalous. The insoluble drugs showed a near case II or zero order release mechanism. The rate of release in descending order was caffeine, acetaminophen, theophylline, salicylic acid and indomethacin. An increase in the release kinetics of the drug was observed on blending with diluents. However, the rate of release varied with the type and amount of blend within the matrix. The mechanism of release due to effect of diluents was found to be anomalous. The rate of drug release decreased upon partial cross-linking and the mechanism of release was found to be of super case II.

Background: Development of new drug carriers would be an interesting approach if it allowed increased efficacy of antibiotics and a reduction in doses, thus reducing the risk of developing resistance. As with most drug carriers, niosomes have been used to improve the selective delivery and the therapeutic index of antimicrobial agents.Methods: In this study, different formulation of niosomes containing ciprofloxacin (CPFX), Span (20, 60 or 80), Tween (20, 60 or 80) and cholesterol were prepared by film hydration method. The release of the drug from different formulations was studied by using Franz diffusion cell. The niosomes were further characterized by optical microscopy and particle size analysis, and their antimicrobial activity was evaluated.Results: Size of the niosomes was significantly dependent on the amount of cholesterol and surfactant type and varied from 8.56 to 61.3 mm. The entrapment efficiency of CPFX niosomes prepared by remote loading was more than 74%. Niosomes composed of Span/Tween 60 provided a higher CPFX release rate than other formulations. The obtained results indicated a diffusion-based mechanism for drug leakage through bilayers. All formulations presented more antibacterial activity as compared to free CPFX solution.Conclusion: Niosomal CPFX appears to be a promising approach in the management of bacterial infections, especially ophthalmic ones, and should be further evaluated by in vivo experiments.

A polyacrylic high oil-adsorption resin was prepared by a suspension polymerization method with butyl acrylate and methyl methacrylate as monomers, benzoyl peroxide as an initiator, poly (vinyl alcohol) (PVA-1788) as a dispersing agent, and divinyl benzene as a cross-linking agent. The effects of dispersing agent, pore-forming agent and cross-linking agent on resins structures were revealed. The maximum specific surface areas and pore volumes of the resulting resins were 853.8 m2/g and 1.188 cm3/g, respectively. These structural parameters endowed excellent adsorbability to the resins. Abamectin, a macrolide insecticide, was selected as a model pesticide, and cyclohexanone was investigated as solvent in adsorption tests. The adsorption isotherms illustrated that adsorption was an endothermic process, and the optimum adsorption temperature was 293 K. Fourier transform infrared spectroscopy, thermo gravimetric analysis, and X-ray diffraction results suggested that abamectin-loaded resins were prepared. The sustained release data indicated that the pesticide-loaded resins exhibited a sustained pesticide release pattern, and the releasing process continued over 15 days in an alcohol medium with the final release rate of over 90 %. These studies established a theory and experimental foundation for the actual application of this method. Meanwhile, the pesticide-loaded resins could be applied to actual production process by adding proper adjuvants in their compositions.

The aim of this study was to prepare and evaluate a solid dosage form of insulin (INS) for oral administration capable to protect insulin from acid and enzymatic degradation in stomach. Insulin was formulated in granules by wet granulation method and microencapsulated with Eudragit L100, an entric coating polymer, using Wurster method. Sodium cholate (SC), aprotinin (AP) and carbopol 934 (CP) were also incorporated into granules as penetration enhancer, protease inhibitor and mucoadhesive respectively. INS content of microcapsules (MC) and the release rate of INS from MC were determined by radioimmunoassay (RIA). The effects of SC, AP and CP on the release of INS were also investigated. The results showed that the present method would be appropriate for preparation of small batches of MC to which active ingredient and excipeints could be easily incorporated. Secondly, formulation conditions could provide insulin stability in the stomach. Eudragit was found to be able to prevent release of insulin in artificial stomach medium. The formulation prepared by the aforementioned method released all its insulin content after 30 mins in a buffer with pH 7.4. It was also shown that CP could delay the release of insulin while AP and SC had no significant effect on the release of INS from coated granules. Finally the formulation marked as ACSF which contained AP, CP and SC was chosen as the most appropriate formulation. It was found that ACSF was able to protect INS from degradation by the stomach medium and release more than 75% of its insulin content into small intestine where INS should be released and absorbed.      

Introduction: Modafinil (MDF) is used orally for the treatment of attention-deficit/ hyperactivity disorder and narcolepsy. It holds low solubility and high permeability; therefore, improving its dissolution properties by preparing nanoformulations can be a promising approach to enhance its oral absorption. Our aims were to prepare and characterize MDF-Eudragit® RS100 (MDF-ERS) nanoparticles by electrospray technique. Methods: Electrosprayed nanoparticles were fabricated by varying MDF to ERS ratios and concentrations. The formulations were characterized by scanning electron microscopy (SEM), differential scanning calorimetry (DSC), powder X-ray diffraction (PXRD), and Fourier-transform infrared spectroscopy (FTIR). Release studies were performed on nanoparticles, physical mixtures, and raw MDF. The release data were fitted to different models to understand the mechanism of the drug release. Results: Electrospraying of MDF and ERS solution resulted in the preparation of nonobeads or nanofibers, and the particulate characteristics of the obtained products were largely controlled by the polymer amount in the solution. PXRD and thermal analyses showed that MDF was an amorphous phase in the structures of nanoparticles. Using FTIR, no interaction was observed between MDF and ERS in nanoparticles. Nanoparticles showed biphasic release profiles and the order of dissolution rates was: nanofibers>MDF>nanobeads. The well-fitted model was Weibull model, indicating a Fickian diffusion as the main mechanism of release. Conclusion: The results suggest that by optimization of variables such as solution concentration of MDF-ERS nanofibers and nanobeads with higher dissolution rates can be made by electrospray. Electrospray deposition as a simple, continuous, and surfactant free method is an excellent choice for preparation of drug loaded polymeric nanoparticles.