Gamma scintigraphic evaluation of the fate of microcrystalline chitosan granules in human stomach

Säkkinen, Mia Susanna; Marvola, Janne; Kanerva, Hanna; Lindevall, Kai; Lipponen, Maija; Kekki, Tommi; Ahonen, Aapo; Marvola, Martti

doi:10.1016/s0939-6411(03)00097-3

Cited by 30 publications

(13 citation statements)

References 18 publications

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“…A valuable physicochemical modification of chitosan, used among others as excipient in drug formulations, is microcrystalline chitosan (MCCh), obtained in form of suspension, powder or granules [6-7]. A polymer of desired chemical properties is prepared by appropriate aggregation of the macromolecules from aqueous solutions of organic acids (via neutralization, coagulation and then precipitation of microcrystalline chitosan) [8].…”

Section: Introductionmentioning

confidence: 99%

Coordinative interaction of microcrystalline chitosan with oxovanadium (IV) ions in aqueous solution

Lichawska

Bodek

Jezierska

et al. 2014

Chemistry Central Journal

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BackgroundChitosan, a non-toxic, biodegradable and biocompatible polysaccharide has attained great interest in pharmaceutical applications, as versatile drug delivery agent. Chitosan has been already shown to serve as vehicle for sustained drug release by chitosan-vanadium(IV) complex from a chitosan gel matrix. Therefore, chitosan gel proved to retain vanadium and preserve its insulin-mimetic efficacy. Nevertheless, there is a lack of reports concerning complexing equilibria in aqueous solution, in particular when using the more advantageous microcrystalline form of chitosan (MCCh). Microcrystalline chitosan shows a number of valuable features as compared with unmodified chitosan.ResultsExperimental studies on complexing interaction between a special form of biomaterial - microcrystalline chitosan as ligand, L = MCCh, of two exemplary degrees of deacetylation DD (lower 79.8%; higher 97.7%) with M = oxovanadium (IV) ions have been carried out potentiometrically at four ligand-to-metal concentration ratios (2:1, 5:1, 8:1, 10:1). Among the five hydrolysis equilibria of VO2+ reported up to now in the literature, under the conditions of the present work i.e. aqueous solutions of ionic strength I = 0.1 (KNO3) and temperature 25.0 ± 0.1°C, the predominating one was (VO)2(OH)2 2+ formation: log β20–2 = −7.01(2). Analysis of potentiometric results permitted to note that degree of deacetylation does not essentially influence the coordination mode of the complexes formed. In the case of both the two DD values, as well as for all the ligand-to-metal ratios, formation of hydroxyl deprotonated MLH−1 and ML2H−2 moieties has been confirmed potentiometrically (log β11–1 = −0.68(2) for DD = 79.8% and −0.68(2) for DD = 97.7%, log β12–2 = −7.64(6) for DD = 79.8% and −5.38(7) for DD = 97.7%).ConclusionMicrocrystalline chitosan coordinates the vanadyl ions by the hydroxyl groups. Interaction of MCCh with VO2+ ions in aqueous solution occurs within pH 5–7. Amounts of alkali excessive towards -NH2 are needed to deprotonate the OH groups. Deprotonation occurring at the chitosan hydroxyl groups permits a “pendant” or “bridge” model of coordination with VO(IV). Lack of complexation via deprotonation of amine groups, typical for simple cations and the molybdenum anion, has been indicated also by FTIR spectroscopy and EPR.Graphical AbstractCoordination modes of VO(IV) with microcrystalline chitosan (MCCh): (a)- pendant model, (b)- bridge model

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Section: Introductionmentioning

confidence: 99%

Coordinative interaction of microcrystalline chitosan with oxovanadium (IV) ions in aqueous solution

Lichawska

Bodek

Jezierska

et al. 2014

Chemistry Central Journal

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“…7 The results of recent studies indicate that MCCh in matrix granules could offer advantages surpassing nonmodified chitosan because the gels form more easily in acidic environments, for example, in the stomach, and drug release is more retarded. 1,8 MCCh might be particularly useful for the preparation of stomach-specific, slow-release dosage forms.…”

Section: Introductionmentioning

confidence: 99%

Interaction of microcrystalline chitosan with Ni(II) and Mn(II) ions in aqueous solution

Bodek

Kufelnicki

2005

J of Applied Polymer Sci

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ABSTRACT:The protonation constant of the NH 2 function was determined by the method of Katchalsky and Spitnik and by the SUPERQUAD fitting procedure. Samples with higher concentrations of chitosan indicated aggregations of polymer chains, which led to a loss in the effective concentration of the ligand (L). It followed, as a result of potentiometric titrations, that an excess of L of microcrystalline chitosan (MCCh) with a deacetylation degree of 0.90 was a complexing agent toward the metal (M), which was Ni(II) or Mn(II). Species ML and ML 2 were accepted by SUPERQUAD for both of the M's, where coordination occurred via the amino nitrogen. For Ni(II), however, the hydroxyl oxygen may also have been an electron-pair donor at lower excesses of MCCh and, by that, made possible the formation of five-membered chelate rings in the hydroxyl deprotonated MLH -1 species. The evaluated formation constants were compared with the values known until now for monomeric d-glucosamine. Additional confirmation of the M-L interaction was determined by the spectrophotometric titration of a Ni(II)-MCCh solution.

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“…Sakkinen and coworkershave described a gamma scintigraphic evaluation of the fate of microcrystalline chitosan granules in the fasted human stomach. [90] The in vivo mucoadhesion of the chitosan formulations was better than that of a control but was erratic, and the authors concluded that, in their present form, the formulations studied were not reliable gastroretentive drug delivery systems.…”

Section: Gamma Scintigraphy Techniquementioning

confidence: 92%

Mucoadhesive microspheres as a controlled drug delivery system for gastroretention

Shadab¹,

Singh²,

Ahuja³

et al. 2012

Syst Rev Pharm

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Gamma scintigraphic evaluation of the fate of microcrystalline chitosan granules in human stomach

Cited by 30 publications

References 18 publications

Coordinative interaction of microcrystalline chitosan with oxovanadium (IV) ions in aqueous solution

Coordinative interaction of microcrystalline chitosan with oxovanadium (IV) ions in aqueous solution

Interaction of microcrystalline chitosan with Ni(II) and Mn(II) ions in aqueous solution

Mucoadhesive microspheres as a controlled drug delivery system for gastroretention

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