Physical gels of a carboxymethyl derivative of scleroglucan: Synthesis and characterization

Dipartimento di Studi di Chimica e Tecnologia delle Sostanze Biologicamente Attive, Sapienza Università di Roma, Rome, Italy.
European Journal of Pharmaceutics and Biopharmaceutics (Impact Factor: 3.38). 12/2007; 67(3):682-9. DOI: 10.1016/j.ejpb.2007.04.010
Source: PubMed


A carboxymethyl derivative of scleroglucan (Scl-CM) was synthesized and characterized through FT-IR, 1H NMR and potentiometer titration. Rheological studies allowed evidencing the effect produced by the introduction of the carboxymethyl moiety on the native polymer. The mechanical spectrum of the scleroglucan solution showed a weak gel behaviour, while the derivative one looked like a system near the gel point, that evolved to a gel state depending on the concentration. This difference could be related to conformational changes due to the introduction of the negative charges on the chains. Different concentrations of Ca2+, added to the aqueous solutions of Scl-CM, were able to deeply modify the resulting system, showing a sharp transition toward a gel like behaviour. Acyclovir was loaded into the hydrogels obtained with different amounts of polymer and salt. The release rate of the drug from these systems was strictly related to both concentrations of salt and polymer. The obtained results suggest a possible employment of these new hydrogels for topical formulations or in situ implantation.

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    • "3.1. Mechanical characterization of DEX-MA/Scl-CM binary mixtures Scl-CM is a very versatile polymer, synthesized in our laboratory and already proposed for different pharmaceutical applications (Casadei et al., 2007; Corrente et al., 2009). The polyanionic characteristics of this derivative make it able to form, in the presence of divalent ions, physical hydrogels whose strength depends on both polymer and salt concentrations. "
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    ABSTRACT: In this paper mixtures of two biocompatible polymers, dextran methacrylate (DEX-MA) with different molecular weights and scleroglucan (Scl), in its native form and as carboxymethyl derivative (Scl-CM), were tested as injectable and in situ cross-linkable systems. Rheological and texture analyses were carried out to better investigate the behavior of this kind of matrices. The combination of these polymers is able to assure adequate mechanical properties, suitable for biomedical applications. In addition swelling studies and in vitro release studies of three different biomolecules were also carried out.
    02/2013; 92(2):1033-9. DOI:10.1016/j.carbpol.2012.10.018
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    • "Dissolved Scleroglucan chains also assume a rod-like triple helical structure, in which the glucose residues are on the outside, thus preventing the helices from coming close to each other and aggregating. In addition, Scleroglucan molecules are in a single chain random coil state when they are dissolved in DMSO or when the pH is higher than 12 (Casadei et al., 2007). Fig. 1 "
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    ABSTRACT: {rtf1ansideff0fonttblf0fnil fcharset0 Arial;} viewkind4uc1pardlang1033fs16 The purpose of this research was to investigate the efficiency of the sorption of copper (II) ions on biopolymeric materials. Blends between poly (vinyl alcohol) [PVA] (DH=98%, DP=900) as a synthetic polymer and scleroglucan (Sclg) as a natural biopolymer have been prepared by repeated freezing- thawing cycles. The sorption capacity of the cryogel against Cu2 + ions has been determined by VIS Spectroscopy. The alteration of the PVA cryogel properties by Sclg addition and by Cu2+ ions sorption has been investigated by FTIR Spectroscopy. The highest efficiency in Cu2+ ions sorption has been obtained for cryogels containing scleroglucan (Sclg) and poly(vinyl alcohol) (PVA) in 1:9 weight ratio by comparing to pure PVA cryogels.par
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    ABSTRACT: A carboxymethyl derivative of scleroglucan (Scl-CM) with a derivatization degree of 65 +/- 5% was synthesized. The rheological behaviour of this novel polymer was studied and compared with that of the starting polymer. We observed that the charged moieties carried on the chains could prevent the triple helix formation of Scl. Scl-CM aqueous solutions behave like true polymer solutions up to 1% w/v, whereas above this concentration a weak gel behaviour was observed. CaCl(2) addition to aqueous Scl-CM solutions led to a physical gel formation; the hydrogel strength was related to polymer and CaCl(2) concentrations. Temperature sweeps, registered at 1 Hz on hydrogels differing in CaCl(2) concentration, evidenced a gel --> sol transition in the range of 30-40 degrees C, depending on the molar ratio between carboxylic groups and Ca(+2). In order to verify a possible use of these hydrogels as drug delivery systems, acyclovir was loaded into the network. Rheological analysis evidenced that the loaded drug can affect the hydrogel elastic modulus. The release of acyclovir in phosphate buffer was evaluated at different temperatures in order to assess the suitability of this novel drug delivery system in topical applications.
    Journal of Materials Science Materials in Medicine 02/2009; 20(5):1081-7. DOI:10.1007/s10856-008-3665-1 · 2.59 Impact Factor
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