Protein encapsulation in biodegradable amphiphilic microspheres

Bouillot, Philippe; Ubrich, Nathalie; Sommer, F.; Đức, Trần Minh; Loeffler, Jean‐Philippe; Dellacherie, Édith

doi:10.1016/s0378-5173(99)00023-x

Cited by 56 publications

(35 citation statements)

References 30 publications

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“…Aging of the films in water prior to exposure to BSA decreased the hydrophobicity of the films as the ester linkages were hydrolyzed and in turn correlated with a significant decrease in the initial BSA adsorption rate. This behavior is consistent with the expected trend that decreased surface hydrophobicity favors decreased protein adsorption (61).…”

Section: Protein Instability During Plg Depot Releasesupporting

confidence: 79%

Poly(ethylene glycol)-Modified Proteins: Implications for Poly(lactide-co-glycolide)-Based Microsphere Delivery

Pai

Tilton

Przybycien

2009

AAPS J

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Abstract. The reduced injection frequency and more nearly constant serum concentrations afforded by sustained release devices have been exploited for the chronic delivery of several therapeutic peptides via poly(lactide-co-glycolide) (PLG) microspheres. The clinical success of these formulations has motivated the exploration of similar depot systems for chronic protein delivery; however, this application has not been fully realized in practice. Problems with the delivery of unmodified proteins in PLG depot systems include high initial "burst" release and irreversible adsorption of protein to the biodegradable polymer. Further, protein activity may be lost due to the damaging effects of protein-interface and protein-surface interactions that occur during both microsphere formation and release. Several techniques are discussed in this review that may improve the performance of PLG depot delivery systems for proteins. One promising approach is the covalent attachment of poly(ethylene glycol) (PEG) to the protein prior to encapsulation in the PLG microspheres. The combination of the extended circulation time of PEGylated proteins and the shielding and potential stabilizing effects of the attached PEG may lead to improved release kinetics from PLG microsphere system and more complete release of the active conjugate.

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Section: Protein Instability During Plg Depot Releasesupporting

confidence: 79%

Poly(ethylene glycol)-Modified Proteins: Implications for Poly(lactide-co-glycolide)-Based Microsphere Delivery

Pai

Tilton

Przybycien

2009

AAPS J

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“…13,26 During the fabrication process, the microspheres were obtained by centrifugation, and the supernatant was collected to determine the amount of protein not encapsulated. The mass of protein encapsulated in microspheres could be easily calculated by mass balance, and then the protein encapsulation efficiency was determined by dividing the mass of the loaded protein by the initial mass of protein.…”

Section: Determination Of the Bsa Content In The Microspheresmentioning

confidence: 99%

Preparation and characterization of BSA‐loaded microspheres based on polyanhydrides

Yang

Zhao

et al. 2011

J of Applied Polymer Sci

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A series of biodegradable PEG-containing polyanhydrides composed of sebacic acid, 1, 6-bis(p-carboxyphenoxy) hexane, and poly (ethylene glycol) (PEG) were used as matrix material for BSA-loaded microspheres. The effects of polymer composition on the microsphere size, entrapment efficiency, in vitro degradation, and in vitro protein release were studied. Microspheres in the size range of 0.8-10 lm were fabricated via a modified double emulsion method and were characterized using scanning electron microscopy. As the content or the molecular weight of PEG was increased in the copolymer, a proportional increase was found in the particle size and the efficiency of BSA entrapment. The in vitro degradation rate of particles could be controlled by varying the polymer composition, increasing as the PEG proportion increased. In vitro release studies of BSA from polyanhydride microspheres revealed that the increased amounts of PEG within microspheres could accelerate the release rate of protein. These studies indicate that the PEG-containing polyanhydrides hold potential for protein delivery applications.

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“…Microspheres based on monomethoxypoly(oxyethylene)-poly(lactic acid) diblock copolymers (MPOE-PLA) did not avoid incomplete release either. Indeed, a plateau was reached after approximately 10 days of BSA release from these microspheres (Bouillot et al, 1999). Brush-like branched polyesters, obtained by grafting PLGA onto poly(vinyl alcohol) (PVA) backbones, were also investigated to allow modification of the release pattern over a broader range (Frauke Pistel et al, 2001).…”

Section: Use Of a More Hydrophilic Polymermentioning

confidence: 99%

How to achieve sustained and complete protein release from PLGA-based microparticles?

Giteau

Venier-Julienne

Aubert-Pouëssel

et al. 2008

International Journal of Pharmaceutics

234

184

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One of the most challenging tasks in the delivery of therapeutic proteins from PLGAbased microparticles is the sustained and complete release of the protein in its native form.The mechanisms responsible for incomplete protein release from these devices are numerous and complex; the beneficial effect of different formulations has often been evaluated in vitro.Strategies employed for overcoming protein destabilization during the release step are reviewed in this paper. Proteins have been protected in the deleterious environment by adding stabilizers to the formulation, or by modifying the protein or the polymer. Alternatively, some strategies have aimed at avoiding the formation of the destabilizing environment. As experimental conditions may influence the results from in vitro release studies, we initially report precautions to avoid adverse effects.

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Protein encapsulation in biodegradable amphiphilic microspheres

Cited by 56 publications

References 30 publications

Poly(ethylene glycol)-Modified Proteins: Implications for Poly(lactide-co-glycolide)-Based Microsphere Delivery

Poly(ethylene glycol)-Modified Proteins: Implications for Poly(lactide-co-glycolide)-Based Microsphere Delivery

Preparation and characterization of BSA‐loaded microspheres based on polyanhydrides

How to achieve sustained and complete protein release from PLGA-based microparticles?

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