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Vansnick, Luc; Couvreur, Patrick; Christiaens-Leyh, Dominique; Roland, Michel

doi:10.1023/a:1016366022712

Cited by 67 publications

(25 citation statements)

References 11 publications

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“…37 Thus, insulin nanospheres were centrifuged for 90 min at 30 000 rpm, lyophilized, and then treated with tetrahydrofuran in order to dissociate the polymeric chains. Polystyrene particles were used as a standard.…”

Section: Methodsmentioning

confidence: 99%

Poly(alkyl cyanoacrylate) Nanospheres for Oral Administration of Insulin

Damgé¹,

Vranckx

Balschmidt

et al. 1997

Journal of Pharmaceutical Sciences

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150

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Poly(alkyl cyanoacrylate) nanocapsules have been successfully used for oral administration of insulin in diabetic rats. This work reports a suitable formulation for insulin-loaded nanospheres composed of full polymeric structures formed by polymerization of isobutyl cyanoacrylate (IBCA) in an acidic medium, insulin (15 U/mL) being added to the polymerization medium 60 min after the onset of polymerization. These nanospheres (MW 364) displayed a mean size of 145 nm and an association rate of 1 U of insulin/mg of polymer. They protected insulin from the degradation by proteolytic enzymes in vitro, especially when they were dispersed in an oily medium (Miglyol 812) containing surfactive agents (Poloxamer 188 and deoxycholic acid). When dispersed in the same medium, insulin-loaded nanospheres (100 U/kg of body weight), administered perorally in streptozotocin-induced diabetic rats, provoked a 50% decrease of fasted glycemia from the second hour up to 10-13 days. This effect was shorter (2 days) or absent when nanospheres were dispersed in water with surfactive agents or not. Using 14C-labeled nanospheres loaded with [125I]insulin, it was found that nanospheres increased the uptake of [125I]insulin or its metabolites in the gastrointestinal tract, blood, and liver while the excretion was delayed when compared to [125I]insulin nonassociated to nanospheres; in addition, 14C- and 125I-radioactivities disappeared progressively as a function of time, parallel to the biological effect. Thus insulin-loaded nanospheres can be considered as a convenient delivery system for oral insulin at the prerequisite that they were dispersed in an oily phase containing surfactants.

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Section: Methodsmentioning

confidence: 99%

Poly(alkyl cyanoacrylate) Nanospheres for Oral Administration of Insulin

Damgé¹,

Vranckx

Balschmidt

et al. 1997

Journal of Pharmaceutical Sciences

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150

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“…5,6 However, the radical polymerization of such monomers has hardly ever been described even in bulk. 7 These monomers are among the most reactive ones and their anionic polymerization is usually spontaneously and quickly initiated by small amounts of a weak base including the hydroxyl ions of water.…”

Section: Introductionmentioning

confidence: 99%

Radical Emulsion Polymerization of Alkylcyanoacrylates Initiated by the Redox System Dextran−Cerium(IV) under Acidic Aqueous Conditions

et al. 2003

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A radical emulsion polymerization of alkylcyanoacrylates (ACA) has been investigated to produce core-shell nanoparticles coated with polysaccharides. It was initiated by dextran on which a radical was created by reaction with cerium(IV) ions in an aqueous acidic medium. The redox radical polymerization developed in this study occurred much faster at pH 1 than the spontaneous anionic polymerization of ACA. It was applied to several ACA and has led to the formation of very stable suspensions of nanoparticles. The mean diameter of the nanoparticles depended on the monomer. Different analysis showed that the polymer forming the nanoparticles was an amphiphilic dextran based copolymer of poly(alkylcyanoacrylate). This copolymer exhibited surfactant properties. The size, morphology, and potential of the nanoparticles have been determined as well as the mobility of the polysaccharide chains at the nanoparticle surface, which was investigated by electron paramagnetic resonance.

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“…Importantly, more than 99% of the polymers in the shell of PBCA MB had a molecular weight below 40 kDa, which is generally considered to be the cutoff size for kidney clearance. [34][35][36][37] Because of this, and also because PBCA becomes hydrophilic after hydrolysis, our results indicate that the individual polymer chains constituting the MB shell can in principle be cleared from the body by renal excretion.…”

Section: Discussionmentioning

confidence: 99%

Physicochemical Characterization of the Shell Composition of PBCA‐Based Polymeric Microbubbles

Appold

Shi

Rütten

et al. 2017

Macromolecular Bioscience

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interest for enhancing drug delivery to tumors and to the brain, via stable or inertial cavitation and sonoporation mechanisms. [3][4][5][6][7] MB-enhanced drug delivery can be realized via direct and indirect approaches. In the direct approach, drug molecules are incorporated into the MB shell, and upon US-mediated MB destruction, they are either locally released from the MB shell, or locally deposited in target tissues in shell fragments, from which they can then gradually be released. [8,9] In case of indirect drug delivery, drugs or drug-loaded nanocarrier materials are coinjected with MB. [10] By temporarily perforating endothelial linings via MB cavitation, coinjected drugs can be delivered more efficiently across the vascular wall, for example in tumors or in the brain, leading to enhanced extravasation, penetration and accumulation at pathological sites. [7,11] MB can be stabilized by a shell of lipids or polymers. Polymeric MB are characterized by a much thicker shell than lipid-based MB. [12,13] This makes polymeric MB more Microbubbles (MB) are routinely used as contrast agents for ultrasound (US) imaging. In recent years, MB have also attracted interest as drug delivery systems. Soft-shelled lipidic MB tend to be more advantageous for US imaging, while hard-shelled polymeric MB appear to be more suitable for drug delivery purposes because of their thicker shell and the resulting higher drug loading capacity. The physicochemical composition of the shell of polymeric MB, however, remains largely unknown. This study sets out to evaluate the molecular weight and polydispersity of the building blocks constituting the shell of poly(butyl cyanoacrylate) (PBCA) MB. Several different PBCA MB were synthesized, varying preparation parameters such as pH, surfactant, stirring speed, and stirring time. Using gel permeation chromatography, it is found that the number average molecular weight (M n ) of the polymer chains in the shell of PBCA MB is 4 kDa, and that >99% of the polymer chains are below 40 kDa. This demonstrates that virtually all polymeric building blocks in the shell of PBCA MB have a size which allows for renal excretion, thereby supporting their use for drug delivery applications.

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Untitled

Cited by 67 publications

References 11 publications

Poly(alkyl cyanoacrylate) Nanospheres for Oral Administration of Insulin

Poly(alkyl cyanoacrylate) Nanospheres for Oral Administration of Insulin

Radical Emulsion Polymerization of Alkylcyanoacrylates Initiated by the Redox System Dextran−Cerium(IV) under Acidic Aqueous Conditions

Physicochemical Characterization of the Shell Composition of PBCA‐Based Polymeric Microbubbles

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