Preparation and evaluation of ethylcellulose microcapsules of indomethacin

Lee, Haeng-Ja; Lee, Min-Hwa; Shim, Chang‐Koo

doi:10.1007/bf02856919

Cited by 6 publications

(1 citation statement)

References 12 publications

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“…When the amount of LM released was plotted against the square root of time (Table 5), we found a linear relationship, that is, the in vitro dissolution study shows that LM release followed Higuchiorder or a diffusion controlled manner. The Higuchi model describes the release from systems where the solid drug is dispersed in an insoluble matrix, and the rate of drug release is related to the rate of drug diffusion (62)(63). Diffusion is related to transport of drug from the dosage matrix to the in vitro fluid depending on the concentration.…”

Section: Discussionmentioning

confidence: 99%

Influence of Oleic Acid on the Rheology and in Vitro Release of Lumiracoxib from Poloxamer Gels

2010

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-Purpose. Transdermal delivery of anti-inflammatory lumiracoxib (LM) could be an interesting strategy to avoid the side effects associated with systemic delivery, but it is ineffective due to the drug poor skin penetration. We have investigated the effects of oleic acid (OA), a lipid penetration enhancer, on the in vitro release of LM from poloxamer-based delivery systems (PBDS). The rheological behavior (shear rate dependent viscosity) and gelation temperature through measurements of optimal sol-gel transition temperatures (T sol-gel ) were also carried out in these systems. Methods. In vitro release studies of LM from PBDS were performed using cellulose acetate as artificial membrane mounted in a diffusion system. The amount of LM released was divided by exposition area (µg/cm 2 ) and these values were plotted as function of the time (h). The flux of the drug across the membrane (J) was calculated from the slope of the linear portion of the plot and expressed as µg/cm 2 /h. The determination of viscosity was carried out at different shear rates (γ) between 0.1-1000 S -1 using a parallel plate rheometer. Oscillatory measurements using a cone-plate geometry rheometer surrounded by a double jacket with temperature varying 4-40°C, was used in order to determine T sol-gel . Results. Increase of both polymer and OA concentrations increases the viscosity of the gels and consequently reduces the in vitro LM release from the PBDS, mainly for gels containing OA at 10.0% (w/w) compared to other concentrations of the penetration enhancer. T sol-gel transition temperature was decreased by increasing viscosity; in some cases the formulation was already a gel at room temperature. Rheological studies showed a pseudoplastic behavior, which facilitates the flow and improves the spreading characteristics of the formulations. Conclusions. Taken together, the results showed that poloxamer gels are good potential delivery systems for LM, leading to a sustained release, and also have appropriate rheological characteristics.

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Section: Discussionmentioning

confidence: 99%

Influence of Oleic Acid on the Rheology and in Vitro Release of Lumiracoxib from Poloxamer Gels

2010

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Development of controlled release oral drug delivery system by membrane-coating method-I

Shim

Kim

et al. 1990

Arch. Pharm. Res.

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Papaverine hydrochloride release from ethyl cellulose-walled microcapsules

Forni

Coppi

Iannuccelli

et al. 1988

Journal of Microencapsulation

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The mechanism of papaverine hydrochloride release from ethyl cellulose-walled microcapsules in both simulated gastric and intestinal fluid is discussed. The microcapsules were prepared by coacervation using different core: wall ratios. The rupture of the thin-walled microcapsules after release in simulated gastric fluid was shown and attributed to the internal osmotic pressure, supporting a mechanism for drug dissolution. The internal osmotic pressure produced only a few small holes in the thin-walled microcapsules after release in simulated intestinal fluid. No rupture of the thick-walled microcapsules after release in either medium was shown. Therefore these release data fitted diffusion-type kinetics. It is suggested that the internal osmotic pressure developed after penetration of the medium is affected by the ratio between the core dissolution rate and the drug diffusion rate through the wall.

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Preparation and evaluation of ethylcellulose microcapsules of indomethacin

Cited by 6 publications

References 12 publications

Influence of Oleic Acid on the Rheology and in Vitro Release of Lumiracoxib from Poloxamer Gels

Influence of Oleic Acid on the Rheology and in Vitro Release of Lumiracoxib from Poloxamer Gels

Development of controlled release oral drug delivery system by membrane-coating method-I

Papaverine hydrochloride release from ethyl cellulose-walled microcapsules

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