Evaluation of guar gum as a compression coat for drug targeting to colon

Krishnaiah, Y. S. R.; Satyanarayana, Srinath; Prasad, Y. V. Rama; Rao, Sumathi

doi:10.1016/s0378-5173(98)00172-0

Cited by 114 publications

(59 citation statements)

References 29 publications

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“…The susceptibility of ChI and ChS in matrix tablets to enzymatic action of colonic bacteria was assessed by continuing the drug release studies in 100 ml of phosphate buffer pH 6.8 containing 2% and 4% w/v rat cecal content (18). Drug release studies were carried out in USP XXIII dissolution apparatus I (75 rpm, 37±0.5°C) with slight modification.…”

Section: Preparation Of Rat Cecal Mediummentioning

confidence: 99%

Chitosan–Chondroitin Sulfate Based Matrix Tablets for Colon Specific Delivery of Indomethacin

Amrutkar¹,

Gattani²

2009

AAPS PharmSciTech

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Abstract. The different approaches for targeting orally administered drugs to the colon include coating with pH-dependent polymers, design of time-release dosage forms, and the utilization of carriers that are degraded exclusively by colonic bacteria. The aim of the present study was to develop a single unit, sitespecific drug formulation allowing targeted drug release in the colon. Matrix tablets were prepared by wet granulation using cross-linked chitosan (ChI) and chondroitin sulfate (ChS) polysaccharides as binder and carrier. ChS was used to form polyelectrolyte complexes (PEC) with ChI, and its potential as a colon-targeted drug carrier was investigated. Indomethacin was used as a model drug. The ChI and ChS PEC was characterized by Fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC) and powder X-ray diffraction studies (XRD). The matrix tablets were tested in vitro for their suitability as colon-specific drug delivery systems. FTIR demonstrated that the PEC forms through an electrostatic interaction between the protonated amine (NH 3 + ) group of ChI with the free carboxylate (COO − ) group and sulfate (SO 4 2− ) group of ChS. DSC and XRD indicated that the PEC has different thermal characteristics from ChI or ChS. The dissolution data demonstrates that the dissolution rate of the tablet is dependent upon the concentration of polysaccharide used as binder and matrix and time of cross-linking. The study confirmed that selective delivery of indomethacin to the colon can be achieved using cross-linked ChI and ChS polysaccharides.

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Section: Preparation Of Rat Cecal Mediummentioning

confidence: 99%

Chitosan–Chondroitin Sulfate Based Matrix Tablets for Colon Specific Delivery of Indomethacin

Amrutkar¹,

Gattani²

2009

AAPS PharmSciTech

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“…Moreover, a larger amount of coat is required to prevent premature drug release due to higher hydrophilicity of the polysaccharides (12). On the other hand, thicker coating, although minimizes precolonic release, induces sustained release following a reasonable lag time instead of burst release of drugs in the absence of specific enzymes or cecal content (13)(14)(15). A general and indeed a more rational approach is, therefore, to develop a compression-coated tablet, the coat of which should erode slowly enough to prevent or at least to minimize the precolonic release and then to provide an immediate burst release of drugs in the colon irrespective of enzymatic metabolism of the polysaccharides by colonic microflora.…”

Section: Introductionmentioning

confidence: 99%

Compression-Coated Tablet for Colon Targeting: Impact of Coating and Core Materials on Drug Release

Maity

2015

AAPS PharmSciTech

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Abstract. This work was envisaged to develop compression-coated tablets using a blend of Ca +2 ion crosslinked carboxymethyl xanthan gum (CMXG) and sodium alginate (SAL) for delayed release of immediate pulse release tablets of prednisolone (PDL) in the colon without the need of colonic bacterial intervention for degradation of the polysaccharide coat. The core tablets containing PDL and other compatible excipients were prepared by direct compression method and subsequently compression coated with different ratios of CMXG and SAL. Long T lag , the time required to restrict the drug release below 10%, and short T rap , the time required for immediate release following the T lag , were considered as suitable release parameters for evaluation of colon targeting of PDL tablets. Among the various compression coats, a blend of CMXG and SAL in a ratio of 1.5:3.5 provided T lag of 5.12±0.09 h and T rap of 6.50±0.05 h. The increase in microcrystalline cellulose (MCC) and crospovidone (CP) in the core tablets did not change T lag significantly although decreased the T rap marginally. Inclusion of an osmogen in the core tablets decreased the T lag to 4.05±0.08 h and T rap to 3.56±0.06 h. The increase in coat weight to 225 mg provided a reasonably long T lag (6.06±0.09 h) and short T rap (4.36±0.20 h). Drug release from most of the formulations followed the Hixson-Crowell equation and sigmoidal pattern as confirmed by the Weibull equation. In conclusion, tablets, compression coated with CMXG and SAL in a ratio of 1.5:3.5 and having 225-mg coat weight, were apparently found suitable for colon targeting.

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“…Até ao momento, o único polissacarídeo utilizado isoladamente no revestimento de sistemas de liberação específica de fármacos no cólon foi a goma guar (Krishnaiah et al, 1998a). Este composto é amplamente utilizado em formulações farmacêuticas como agente desintegrante, estabilizante e espessante.…”

Section: Hidróliseunclassified

Liberação específica de fármacos no cólon por via oral. II - Tipos de sistemas utilizados

Freire¹,

Podczeck²,

Sousa³

et al. 2006

Rev. Bras. Cienc. Farm.

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Evaluation of guar gum as a compression coat for drug targeting to colon

Cited by 114 publications

References 29 publications

Chitosan–Chondroitin Sulfate Based Matrix Tablets for Colon Specific Delivery of Indomethacin

Chitosan–Chondroitin Sulfate Based Matrix Tablets for Colon Specific Delivery of Indomethacin

Compression-Coated Tablet for Colon Targeting: Impact of Coating and Core Materials on Drug Release

Liberação específica de fármacos no cólon por via oral. II - Tipos de sistemas utilizados

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