Preparation of dual crosslinked alginate–chitosan blend gel beads and in vitro controlled release in oral site-specific drug delivery system

Yang, Xu; Zhan, Changyou; Fan, Lihong; Wang, Le; Zheng, Hua

doi:10.1016/j.ijpharm.2006.12.019

Cited by 225 publications

(110 citation statements)

References 29 publications

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“…When the cationic charge was increased, particles with a size in the order of mm were obtained which had an even surface. Similarly, the International Journal of Chemical Engineeringcomplexation of alginate with chitosan also has porous walls (data not shown), and Xu et al [29] showed that the mixture of AA with CS forms a random network that decreases pore formation with the increase in AA.…”

Section: Alginic Acid-(aa-) Based Hydrogelsmentioning

confidence: 90%

Polyelectrolyte Complexation versus Ionotropic Gelation for Chitosan-Based Hydrogels with Carboxymethylcellulose, Carboxymethyl Starch, and Alginic Acid

Henao

Delgado

Contreras

et al. 2018

International Journal of Chemical Engineering

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e preparation of gels by charge interaction methods has been extensively studied, but it is not yet clear how these methods influence gel characteristics. e objective of this work was to study differences in morphology and surface charge of hydrogels prepared by ionotropic gelation, polyelectrolyte complexation, and a combination of both methods. us, the anionic charge was provided by carboxymethylcellulose (CMC), carboxymethylated starch (CMS), and alginic acid (AA); calcium chloride (CaCl 2 ) and chitosan (CS) were used for the ionotropic gelation and polyelectrolyte complexation, respectively. ose materials are commercially available, have low toxicity, and are widely used in the area. ese compounds interact through physical crosslinks, which are affected by physical changes of the medium. Our results showed that these two methods produced changes in the morphology of the hydrogels. CMC gels exhibited larger pores in the presence of CaCl 2 . In polyelectrolyte complexation, CMS produced an increased agglomeration of particles, while the addition of CaCl 2 to AA generated dispersed particles of size in the order of millimeters. Mixing both ionotropic gelation and polyelectrolyte complexation methods yielded gels of varied charge (568 mV for CMC, 502 mV for CMS, and 1713 mV for AA). FTIR spectra of the hydrogels showed interactions between the different polymeric compounds, being the greatest changes between 1250 and 1600 cm −1 , due possibly to the replacement of Na by Ca at crosslinking points. erefore, the method of gel preparation employed had a major influence on the size and pore distribution, parameters which in turn influence encapsulation and drug delivery in these systems.

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Section: Alginic Acid-(aa-) Based Hydrogelsmentioning

confidence: 90%

Polyelectrolyte Complexation versus Ionotropic Gelation for Chitosan-Based Hydrogels with Carboxymethylcellulose, Carboxymethyl Starch, and Alginic Acid

Henao

Delgado

Contreras

et al. 2018

International Journal of Chemical Engineering

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“…Alginate is a linear copolymer made up of β-Dmannuronic acid and α-L-guluronic acid in different configurations (22,23). The carboxyl groups present on the alginate molecule is responsible for its pH-sensitive nature (23).…”

Section: Introductionmentioning

confidence: 99%

Optimization of a Dual Mechanism Gastrofloatable and Gastroadhesive Delivery System for Narrow Absorption Window Drugs

et al. 2011

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Abstract. In order to overcome poor bioavailability of narrow absorption window drugs, a gastrosphere system comprising two mechanisms of gastric retention, namely buoyancy and gastroadhesion, has been investigated in this study employing poly(lactic-co-glycolic acid) (PLGA), polyacrylic acid (PAA), alginate, pectin, and a model drug metformin hydrochloride. Fifteen formulations were obtained using a Box-Behnken statistical design. The gastrosphere yield was above 80% in all cases; however, due to the high water solubility of metformin, drug entrapment efficacy was between 18% and 54%. Mean dissolution time and gastroadhesive strength were used as the formulation responses in order to optimize the formulation. Furthermore, the molecular mechanics force field simulations were performed to corroborate the experimental findings. Drug release profiles revealed three different release kinetics, namely, burst, first-order and zero-order release. Varying gastroadhesive results were obtained, and were highly sensitive to changes in polymer concentrations. FTIR revealed that strong bonds of PAA and PLGA were retained within the gastrosphere. Surface area and porosity analysis provided supporting evidence that the lyophilization process resulted in a significant increase in the porosity. Analysis of the surface morphology by SEM revealed that air pockets were spread over the entire surface of the gastrosphere, providing a visual proof of the high porosity and hence low density of the gastrosphere. The spatial disposition and energetic profile of the sterically constrained and geometrically optimized multi-polymeric complex of alginate, pectin, PAA, and PLGA corroborated the experimental results in terms of in vitro drug release and gastroadhesive strength of the fabricated gastrospheres.

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“…[38][39][40][41][42][43][44] The drug release property of an alginate matrix is strongly governed by the composition of the uronic acid sequences. [1,105,106] The mannuronic acid-rich alginate matrix gives lower drug release rates in dissolution medium of pH 1.2 but higher drug release rates at pH 6.8 when compared with guluronic acid-rich Beads [6,[64][65][66][67][68][69][70][71][72][73][74] Chitosan is introduced as chitosan membrane or directly as alginate-chitosan blend in alginate beads crosslinked by calcium chloride via ionotropic gelation method. The alginate-chitosan beads can be further crosslinked through reacting chitosan with sodium sulfate.…”

Section: Oral Drug Deliverymentioning

confidence: 99%

Alginate graft copolymers and alginate–co-excipient physical mixture in oral drug delivery

Wong

2011

Journal of Pharmacy and Pharmacology

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Objectives Use of alginate graft copolymers in oral drug delivery reduces dosage form manufacture complexity with reference to mixing or coating processes. It is deemed to give constant or approximately steady weight ratio of alginate to covalently attached co-excipient in copolymers, thereby leading to controllable matrix processing and drug release. This review describes various grafting approaches and their outcome on oral drug release behaviour of alginate graft copolymeric matrices. It examines drug release modulation mechanism of alginate graft copolymers against that of co-excipients in non-grafted formulations. Key findings Drug release from alginate matrices can be modulated through using either co-excipients or graft copolymers via changing their swelling, erosion, hydrophobicity/ hydrophilicity, porosity and/or drug adsorption capacity. However, it is not known if the drug delivery performance of formulations prepared using alginate graft copolymers is superior to those incorporating graft-equivalent co-excipient physically in a dosage form without grafting but at the corresponding graft weight, owing to limited studies being available. Conclusions The value of alginate graft copolymers as the potential alternative to alginate-co-excipient physical mixture in oral drug delivery cannot be entirely defined by past and present research. Such an issue is complicated by the lack of green chemistry graft copolymer synthesis approach, high grafting process cost, complications and hazards, and the formed graft copolymers having unknown toxicity. Future research will need to address these matters to achieve a widespread commercialization and industrial application of alginate graft copolymers in oral drug delivery

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Preparation of dual crosslinked alginate–chitosan blend gel beads and in vitro controlled release in oral site-specific drug delivery system

Cited by 225 publications

References 29 publications

Polyelectrolyte Complexation versus Ionotropic Gelation for Chitosan-Based Hydrogels with Carboxymethylcellulose, Carboxymethyl Starch, and Alginic Acid

Polyelectrolyte Complexation versus Ionotropic Gelation for Chitosan-Based Hydrogels with Carboxymethylcellulose, Carboxymethyl Starch, and Alginic Acid

Optimization of a Dual Mechanism Gastrofloatable and Gastroadhesive Delivery System for Narrow Absorption Window Drugs

Alginate graft copolymers and alginate–co-excipient physical mixture in oral drug delivery

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