Structure and behaviour in hydrophilic matrix sustained release dosage forms: 3. The influence of pH on the sustained-release performance and internal gel structure of sodium alginate matrices

Hodsdon, Alison C.; Mitchell, John R.; Davies, Martyn C.; Melia, Colin D.

doi:10.1016/0168-3659(94)00076-7

Cited by 130 publications

(54 citation statements)

References 12 publications

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“…The L-arabinofuranosyl groups may also bind non-specific water. The substituted flexible chains can diffuse into the mucosal layer and remain adhered for long periods 33 . The decreased mucoadhesion of beads in phosphate buffer may result from erosion of calcium ions which form a crosslinked structure 7 .…”

Section: Resultsmentioning

confidence: 99%

“…The release of GCD from alginate-ispaghula beads adhered to fresh goat intestinal mucosa were performed in acidic (0.1 N HCl) as well as alkaline phosphate buffer (pH 7.4) media 33 . The GCD-loaded alginateispaghula beads were weighed accurately (100 mg) and spread out on the intestinal tissue specimen (goat intestinal mucosa) attached to a glass support.…”

Section: Ex Vivo Drug Release Studymentioning

confidence: 99%

“…The GCD loaded alginate-ispaghula beads were prepared by the ionotropic gelation method using CaCl 2 as a counter ion 33 . The dispersions of sodium alginate and ispaghula were prepared separately in deionized water.…”

Section: Preparation Of Alginate-ispaghula Beads Loaded With Gliclazidementioning

confidence: 99%

“…Mucoadhesive microcapsules of GCD using sodium alginate and mucoadhesive polymers such as sodium carboxymethyl cellulose, carbopol 934P, and hydroxy propylmethyl cellulose use the orifice-ionic gelation method 32 . Although the efficacy of alginate-ispaghula beads for delivery of metformin HCl has been investigated 33 , no attempt has been made to formulate a GCD loaded alginate based bead system using an ispaghula husk gel blend.…”

Section: Introductionmentioning

confidence: 99%

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Nayak¹,

Hasnain²,

Beg³

et al. 2010

ScienceAsia

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Novel mucoadhesive beads were developed and evaluated for oral controlled release of the hypoglycaemic agent gliclazide. Various formulations of mucoadhesive beads were prepared using two different natural polymers, alginate and ispaghula, in various stoichiometric proportions with CaCl2 as a source of counter ions. The mucoadhesive beads were characterized for entrapment efficiency, particle size, surface morphology, and swelling index. The kinetics of drug release and their mucoadhesive nature in vitro using goat intestinal mucosa was also investigated at various physiological pH conditions. The effects of various proportions of the two polymers along with the effect of various percentages of counter ions on mucoadhesion property, size, entrapment efficiency, and drug release behaviour were studied. The effective mucoadhesion property with sustained release profile was observed from optimized mucoadhesive beads consisting of alginate and ispaghula husk (1:1) and polymer (2:1) with 5-10% w/v counter ions (CaCl2). These formulations showed optimum mucoadhesion behaviour having more than 70% w/v of drug entrapment and particle sizes of 896.7 ± 0.8 and 920.6 ± 1.2 µm, respectively.

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Section: Resultsmentioning

confidence: 99%

Section: Ex Vivo Drug Release Studymentioning

confidence: 99%

Section: Preparation Of Alginate-ispaghula Beads Loaded With Gliclazidementioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Untitled

Nayak¹,

Hasnain²,

Beg³

et al. 2010

ScienceAsia

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“…The in vitro release profile of up to 12 h was found to increase patient compliance and the therapeutic efficacy of sertraline. Hence in the present study, commonly used extended release polymers such as sodium alginate, aqueous dispersion of ethyl cellulose and acrylic polymers were evaluated to prepare matrix pellets (Hodsdon et al, 1995;Bhagat et al, 1990).…”

Section: Introductionmentioning

confidence: 99%

Compression and evaluation of extended release matrix pellets prepared by the extrusion/spheronization process into disintegrating tablets

Pai¹,

Kohli

Shrivastava

2012

Braz. J. Pharm. Sci.

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In this study, a novel approach for compression of matrix pellets into disintegrating tablets has been studied in an attempt to overcome the issues pertaining to rupture of polymer coat during compression of reservoirtype pellets. Extended release matrix pellets were prepared by the extrusion/spheronization technique using commercially available aqueous dispersions of ethyl cellulose, acrylic polymers and sodium alginate at 10%, 20% and 30%w/w levels. Sertraline hydrochloride was used as the model drug and an in vitro release profile of 12 h was targeted. Tablets containing matrix pellets were prepared by the direct compression process. Acceptance Value, a pharmacopeial test, was applied to study the uniformity of drug distribution. Effect of compression force (2-6 kN), extrusion screen aperture size, diluent blend composition and pellet percentage on drug release and acceptance value were studied. As polymer is uniformly distributed within each pellet, the drug release pattern from uncompressed pellets was comparable to compressed tablets. Surface morphological changes due to calcium chloride treatment were observed using Scanning electron microscopy. The pellet segregated from the surface of the tablet was found to be flattened in the direction of applied compression force with minor deformities. In conclusion, matrix pellets can constitute an alternative approach to reservoir-type pellets in obtaining disintegrating tablets for extended delivery of drugs.Uniterms: Pellets/extended release/evaluation. Pellets/obtention. Pellets/compression. Extrusion/spheronization technique.Nesse trabalho, estudou-se nova abordagem para a compressão de matrizes de péletes em comprimidos desintegrantes, com o intuito de resolver os problemas relativos à ruptura do polímero de revestimento durante a compressão dos péletes do tipo reservatório. Matrizes de péletes de liberação estendida foram preparadas pela técnica de extrusão/esferonização, utilizando dispersões aquosas comercialmente disponíveis de etil celulose, polímeros acrílicos e alginato de sódio a 10%, 20% e 30% p/p. O cloridrato de sertralina foi utilizado como fármaco modelo e focalizou-se no perfil de liberação in vitro de 12 horas. Os comprimidos contendo matrizes de péletes foram preparados pelo processo de compressão direta. O valor de aceitação, teste farmacopéico, foi aplicado para estudar a uniformidade de distribuição do fármaco. O efeito da força de compressão (2-6 kN), o tamanho da abertura de extrusão, a composição da mistura diluente, a porcentagem de pélete na liberação de fármaco e o valor de aceitação foram estudados. Como o polímero é uniformemente distribuído dentro de cada pélete, o padrão de liberação do fármaco dos péletes não-comprimidos foi comparável àquele dos comprimidos. As mudanças morfológicas da superfície devidas ao tratamento com cloreto de cálcio foram observadas utilizandose a microscopia eletrônica de varredura. O pélete segregado da superfície do comprimido mostrou-se plano em direção à força de compressão aplicada com menores defor...

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Application of Polymer Combinations in Extended Release Hydrophilic Matrices

Nokhodchi

Palmer²,

Asare-Addo

et al. 2015

Handbook of Polymers for Pharmaceutical Technologies

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DESCRIPTIONPolymers are one of the most fascinating materials of the present era finding their applications in almost every aspects of life. Polymers are either directly available in nature or are chemically synthesized and used depending upon the targeted applications.Advances in polymer science and the introduction of new polymers have resulted in the significant development of polymers with unique properties. Different kinds of polymers have been and will be one of the key in several applications in many of the advanced pharmaceutical research being carried out over the globe.This 4-partset of books contains precisely referenced chapters, emphasizing different kinds of polymers with basic fundamentals and practicality for application in diverse pharmaceutical technologies. The volumes aim at explaining basics of polymers based materials from different resources and their chemistry along with practical applications which present a future direction in the pharmaceutical industry. Each volume offer deep insight into the subject being treated.

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Structure and behaviour in hydrophilic matrix sustained release dosage forms: 3. The influence of pH on the sustained-release performance and internal gel structure of sodium alginate matrices

Cited by 130 publications

References 12 publications

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Compression and evaluation of extended release matrix pellets prepared by the extrusion/spheronization process into disintegrating tablets

Application of Polymer Combinations in Extended Release Hydrophilic Matrices

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