Use of Microwave in Processing of Drug Delivery Systems

Wong, Tin Wui

doi:10.2174/156720108783954842

Cited by 58 publications

(29 citation statements)

References 94 publications

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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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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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“…Microwave has been utilized to design controlled-release alginate, alginate-chitosan, pectinate-chitosan and poly(methyl vinyl etherco-maleic acid) beads [2][3][4][5]. The drug release characteristics of these beads were dependent on the propensity of polymer-polymer and drug-polymer interaction brought about by microwave.…”

Section: Introductionmentioning

confidence: 99%

“…They reported that the drug release propensity of microwave-treated sample is greatly higher than those of pure drug, samples which are untreated by microwave or treated by vacuum at 100 • C, or obtained by solvent deposition method. A review of microwave application in design of drug delivery system, namely agglomerates, beads, tablets, microparticles, nanoparticles and solid dispersion, has been reported lately by Wong (2008) [4].…”

Section: Introductionmentioning

confidence: 99%

Effects of Microwave on Water and Its Influence on Drug Dissolution

Wong¹,

Iskhandar²,

Kamal³

et al. 2009

PIER C

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Abstract-Use of water with different molecular mobilities could affect drug dissolution of a dosage form and such profile of water might be modifiable using microwave. This study investigated the effects of microwave on water and its influences on dissolution of free drugs and drugs in calcium-crosslinked alginate beads using sulphanilamide and sulphamerazine as hydrophilic and hydrophobic model drugs respectively. The water was treated by microwave at 300 W or without pre-treatment. The drug dissolution, pH and molecule mobility profiles of untreated and microwave-treated water were examined. Microwave-treated water had higher pH and water molecule mobility. The latter was characterized by higher conductivity, lower molecular interaction and crystallinity profiles. The dissolution of hydrophilic and hydrophobic free or encapsulated drugs was enhanced using microwave-treated water due to its higher molecular mobility. The untreated water of the same pH as microwave-treated water did not enhance drug dissolution. The drug dissolution from beads was increased by higher water uptake leading to matrix erosion and pore formation using microwave-treated water and was not promoted by the formation of non-crosslinked hydrated alginic acid matrix in untreated water of lower pH. Microwave treatment of water increased water molecule mobility and can promote drug dissolution.

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“…The transmission of microwave to an object results in vibration of molecules by induced or permanent dipoles. The microwave technology has been used to design controlled release solid matrices of pectin, alginate, chitosan, poly(methylvinylether-co-maleic acid) and gelatin prepared by ionotopic gelation, coacervation and denaturation processes [3][4][5][6][7][8]. The drug release property of these solid matrices is modified through subjecting the formed products to microwave treatment in solid or liquid state.…”

Section: Introductionmentioning

confidence: 99%

“…The dynamics and mechanism of solid particle assembly are different from matrices formed via ionotropic gelation, coacervation and denaturation processes whereby the former produces spheroids via wetting of solid powder by binding liquid whereas the latter involves the transformation of polymer solution into solid polymeric matrices. Under the influence of microwave, the changes in interaction propensity between polymer and/or drug of an object is known to be affected by its physicochemical attributes which in turn are a function of its assembly conditions [8]. The ease of modifying drug release property of spheroids by microwave can be lower than matrices prepared by gelation, coacervation and denaturation methods as polymer and/or drug particles in a spheroid are assembled with a larger inter-particulate distance and their interaction propensity can be less inducible by microwave.…”

Section: Introductionmentioning

confidence: 99%

Chitosan Spheroids With Microwave Modulated Drug Release

Zakaria

Wong²

2009

PIER

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Abstract-The interplay effects of matrix formulations with microwave on drug release were investigated using an agglomerate system. Chitosan spheroids were formulated with stearic acid and/or sodium chloride by extrusion-spheronization technique, and chlorpheniramine maleate as water-soluble model drug. The spheroids were treated by microwave at 80 W for 5 to 40 min. The profiles of drug dissolution, drug content, drug-polymer interaction, polymer-polymer interaction, sodium leaching, matrix morphology and integrity were determined. Unlike chitosan matrix prepared by ionotropic gelation method, the retardation of drug release from chitosan spheroids by microwave required a more complex formulation containing both stearic acid and sodium chloride unless a high stearic acid fraction was used. These spheroids demonstrated a high resistance to disintegration during dissolution owing to salt-induced bridging by sodium chloride. In response to microwave, sodium chloride aided stearic acid spread and effected domain interaction via C = O moiety over a matrix with reduced specific surface area thereby reducing drug dissolution. The drug release of spheroids can be retarded by microwave through promoting the layering of hydrophobic stearic acid in a matrix structure sustained by sodium chloride.

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Use of Microwave in Processing of Drug Delivery Systems

Cited by 58 publications

References 94 publications

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

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

Effects of Microwave on Water and Its Influence on Drug Dissolution

Chitosan Spheroids With Microwave Modulated Drug Release

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