Microencapsulation of ibuprofen and Eudragit (R) RS 100 by the emulsion solvent diffusion technique

ArticleinInternational Journal of Pharmaceutics 218(1-2):1-11 · June 2001with78 Reads
DOI: 10.1016/S0378-5173(00)00686-4 · Source: PubMed
  • 6.96 · National Institute of Technology Tiruchirappalli
The emulsion solvent diffusion was employed to prepare modified release microspheres of ibuprofen. The technique was optimised for the following processing variables: the absence/presence of baffles in the reaction vessel, agitation rate and drying time. Thereafter, the influence of various formulation factors on the microencapsulation efficiency, in vitro drug release and micromeritic properties was examined. The variables included the methacrylic polymer, Eudragit(R) RS 100, ibuprofen content and the volume of ethanol used during microencapsulation. The results obtained were then interpreted on a triangular phase diagram to map the region of microencapsulation, as well as those formulations that yielded suitable modified release ibuprofen microspheres.
    • "The homogenization speed affects the dispersion of the emulsifier, which helps form stable nanocapsules, nanoemulsions or micelles. Low emulsifier dispersion leads to a large particle size and heterogeneous size distribution (Kim et al., 2012; Perumal, 2001; Surassmo et al., 2010). "
    [Show abstract] [Hide abstract] ABSTRACT: The effect of trans-cinnamaldehyde emulsions were studied by observing physical and microbial properties. Moreover, trans-cinnamaldehyde emulsions were applied into real food system like watermelon juice. Nano-sized (<200nm) trans-cinnamaldehyde emulsions were produce by using optimum mass ratio of trans-cinnamaldehyde and Tween®20 (1:3) and then high-energy emulsification (10,000rpm high speed homogenization and 20,000 psi high pressure homogenization) was carried out. Trans-cinnamaldehyde was encapsulated as over 70% efficiency and its encapsulation efficiency was maintained higher at 0.8wt% trans-cinnamaldehyde emulsions. For the antibacterial activity results, 0.8wt% trans-cinnamaldehyde emulsions which lowest concentration showed inhibition of Salmonella Typhimurium and Staphylococcus aureus except Escherichia coli growth at both pure water and water melon juice.
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    • "It is evident that drug release rate was increased considerably when volume of dispersed phase increased. This is expected because smaller particle size, with increased volume of dispersed phase, provides higher surface area for dissolution [23, 24]. "
    [Show abstract] [Hide abstract] ABSTRACT: In order to evaluate the wall forming and sustained release potential of the resin of Boswellia papyrifera in diclofenac sodium microcapsules, different formulations were prepared by the emulsion solvent evaporation method at varying polymer to drug ratios. It was found that formulations with polymer to drug ratio ranging from 2:1 to 5:1 resulted in microcapsules as confirmed from optical microscopy observations. The effects of other variables such as stirring rate, temperature and volume of dispersed phase, on characteristics of microcapsules were also studied. Preliminary studies revealed that the polymer to drug ratio and stirring rate are the primary factors which affect the response variables (encapsulation efficiency and release rate). Thus, central composite design (CCD) was employed to optimize the encapsulation efficiency and release rate with respect to polymer to drug ratio and stirring rate. Accordingly, the central composite design provided an optimum region with an encapsulation efficiency of 27.24 % and release rate of 26.76 h-1/2 at 3.7:1 polymer to drug ratio and 1200 rpm stirring rate. The optimum formulation provided discrete, spherical and freely flowing microcapsules. The in vitro drug release exhibited minimum burst release with sustained release for 12 h. Kinetic study showed the optimized formulation followed Higuchi square root kinetic model with non-Fickian diffusion mechanism. FT-IR analysis indicated that there is no incompatibility between diclofenac sodium and the resin of B. papyrifera. Thus, the resin of B. papyrifera could be a potential alternative wall material for microencapsulation. Keywords: Olibanum resin, diclofenac sodium, microcapsules, central composite design, release kinetics.
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    • "Stirring speed is the most important parameter for controlling the drug/matrix dispersion's droplet size in the continuous phase. It was shown that increasing the stirring speed generally results in decreased microparticle size, as it produces smaller emulsion droplets through stronger shear forces and increased turbulence (Perumal, 2001). In this study, the high stirring speed (600 rpm) produced microparticles with small particle size while the lower stirring speed (200 rpm) produced large sized microparticles. "
    [Show abstract] [Hide abstract] ABSTRACT: Emulsification/internal gelation has been suggested as an alternative to extrusion/external gelation in the encapsulation of several compounds including non-steroidal anti-inflammatory drugs such as diclofenac sodium. The objective of the present study was a trial to formulate diclofenac sodium as controlled release microparticles that might be administered once or twice daily. This could be achieved via emulsification/internal gelation technique applying Box-Behnken design to choose these formulae. Box-Behnken design determined fifteen formulae containing specified amounts of the independent variables, which included stirring speed in rpm (X1), drug:polymer ratio (X2) and the surfactant span 80% (X3). The dependent variables studied were cumulative percent release after two hours (Y1), four hours (Y2) and eight hours (Y3). The prepared microparticles were characterized for their production yield, sizes, shapes and morphology, entrapment efficiency and Diclofenac sodium in vitro release as well. The results showed that the production yield of the prepared diclofenac sodium microparticles was found to be between 79.55% and 97.41%. The formulated microparticles exhibited acceptable drug content values that lie in the range 66.20-96.36%. Also, the data obtained revealed that increasing the mixing speed (X1) generally resulted in decreased microparticle size. In addition, scanning electron microscope images of the microparticles illustrated that the formula contains lower span concentration (1%) in combination with lower stirring speed (200 rpm) which showed wrinkled, but smooth surfaces. However, by increasing surfactant concentration, microspheres' surfaces become smoother and slightly porous. Kinetic treatment of the in vitro release from drug-loaded microparticles indicated that the zero order is the drug release mechanism for the most formulae.
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