Effect of Polyisobutylene on Ethylcellulose-Walled Microcapsules: Wall Structure and Thickness of Salicylamide and Theophylline Microcapsules

Benita, S.; Donbrow, M.

doi:10.1002/jps.2600710217

Cited by 59 publications

(10 citation statements)

References 6 publications

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“…Similarly, the present investigation was aimed at developing a polymeric system employing a release retardant polymer ethyl cellulose (EC) in combination with pHsensitive Eudragit's (EL100 or ES100) to form a pH and transit time controlled multiparticulate formulation of indomethacin for controlled release colonic delivery. EC, a hydrophobic water-insoluble polymer, has been widely used for microencapsulation to retard the release of number of water-soluble drugs or to improve the stability (Sajeev et al 2002, Benita andDonbrow 2006). The technique employed in the present study was phase separation-coacervation induced by solvent evaporation.…”

Section: Introductionmentioning

confidence: 98%

Microspheres with pH modulated release: Design and characterization of formulation variables for colonic delivery

Chandran¹,

Sanjay²,

Asghar³

2009

Journal of Microencapsulation

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For the design and development of any novel formulation, assessment of compatibility of drug with excipients by different techniques such as thermal and isothermal stress testing are recommended. During pre-formulation studies common methods like UV-Spectrophotometric methods, FTIR are used for the study of compatibility. In the present investigation drug-excepient compatibility study of was conducted for metronidazole with ethyl cellulose to formulate microspheres by using different ratio of drug: polymer for colonic delivery. The drug and polymer mixtures were stored at 50 °C for 2 weeks. The samples were then characterized using UV Spectrophotometric method, FTIR. The results show that metronidazole was compatible with ethyl cellulose; hence ethyl cellulose can be used for formulation of metronidazole microspheres. Microspheres were prepared by modified Novel Quasiemulsification solvent-diffusion method to study the effect of ethyl cellulose on drug release with different proportions of metronidazole and ethyl cellulose. Prepared microspheres of ethyl cellulose were evaluated for size, morphology, sphericity study, percentage yield, loose surface crystal study, drug content and entrapment efficiency. In vitro drug release study was conducted by buffer change method to mimic Gastro Intestinal environment. The investigations revealed that microspheres prepared with metronidazole: ethyl cellulose ratio (1:2) show only 19.394 ±0.67% drug release in first 5 hours and 46.72 ±0.69% in 12 hours, which prove the potentiality of ethyl cellulose for colonic delivery of drugs.

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Section: Introductionmentioning

confidence: 98%

Microspheres with pH modulated release: Design and characterization of formulation variables for colonic delivery

Chandran¹,

Sanjay²,

Asghar³

2009

Journal of Microencapsulation

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“…They concluded that the increase of viscosity and protective colloid concentration of the PIB modulated the rates of EC separation, growth, and aggregation processes and led to stabilization of growth and suppressed regular surface nucleation and crystallization of the polymer. In a related article [40], the same authors prepared microcapsules of salicylamide and theophylline by coacervation of EC 100 cp in the presence of polyisobutylene (PIB) from cyclohexane solution. The 50% dissolution time of salicylamide in water of microcapsules from solutions containing 5, 6 or 7% PIB was about 3 hours.…”

Section: Control Of Drug Release Through Film Coatingmentioning

confidence: 99%

“…The 50% dissolution time for the largest particles (1850 micrometers) was 24 minutes for microcaps with 1:2 core:wall ratio. Benita and Donbrow [40] reported the dissolution of salicylamide from ethyl cellulose microcapsules as first order plots. These microcapsules were prepared by coacervation of EC in the presence of a protective colloid, polyisobutylene.…”

Section: Control Of Drug Release Through Film Coatingmentioning

confidence: 99%

Aliphatic Polyesters and Cellulose-Based Polymers for Controlled Release Applications

Chang¹,

Price

1988

J Biomater Appl

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“…Theophylline, a xanthine derivative having antiasthmatic, diuretic and cardiac stimulant properties (Anderson et al 1983) has been investigated as a sustained release formulation by encapsulation in various synthetic (Benita and Donbrow 1982, Motycka et al 1985, Lin and Yang 1987, Pongpaibul et al 1988 and natural polymeric microspheres (Thanoo et al 1992, Latha andJayakrishnan 1994).…”

Section: Introductionmentioning

confidence: 98%

Evaluation of an aliphatic polyurethane as a microsphere matrix for sustained theophylline delivery

Subhaga

Ravi

Sunny

et al. 1995

Journal of Microencapsulation

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In spite of several biomedical applications of polyurethanes, very little attention has been focused on these polymers for controlled drug delivery. In this study, an aliphatic polyurethane, Tecoflex, was evaluated as a microsphere matrix for the controlled release of theophylline. Polyurethane microspheres containing theophylline were prepared using a solvent evaporation technique from a dichloromethane solution of the polymer containing the drug. A dilute solution of poly(vinyl alcohol) served as the dispersion medium. Microspheres of good spherical geometry having theophylline content of 35% could be prepared by the technique. The release of the drug from the microspheres was examined in simulated gastric and intestinal fluids at 37 degrees C. While a large burst effect was observed in gastric fluid, in the intestinal fluid a close to zero-order release was seen. Attempts were made to modulate the release by incorporating poly(ethylene glycol) in the matrix and also coating the spheres with paraffin wax. Preliminary data indicate that polyurethanes could be interesting matrices for controlled drug delivery.

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Effect of Polyisobutylene on Ethylcellulose-Walled Microcapsules: Wall Structure and Thickness of Salicylamide and Theophylline Microcapsules

Cited by 59 publications

References 6 publications

Microspheres with pH modulated release: Design and characterization of formulation variables for colonic delivery

Microspheres with pH modulated release: Design and characterization of formulation variables for colonic delivery

Aliphatic Polyesters and Cellulose-Based Polymers for Controlled Release Applications

Evaluation of an aliphatic polyurethane as a microsphere matrix for sustained theophylline delivery

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