Insulin-loaded biodegradable PLGA microcapsules: initial burst release controlled by hydrophilic additives

Yamaguchi, Yoko; Takenaga, Mitsuko; Kitagawa, Aki; Ogawa, Yasuaki; Mizushima, Yutaka; Igarashi, Rie

doi:10.1016/s0168-3659(02)00060-3

Cited by 135 publications

(86 citation statements)

References 19 publications

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“…Therefore, the development of a novel DDS for EPO in the treatment of renal anemia is very necessary. In DDS research, poly(lactic glycolic acid) (PLGA) has often been used as a carrier for the sustained release of therapeutic agents [2,10,28,32,33]. PLGA and block copolymer microspheres incorporating EPO formulated by a microencapsulation method have shown the sustained release of EPO for between two weeks and one month in an in vitro test [20,21,24].…”

Section: Discussionmentioning

confidence: 99%

Sustained Efficacy of Erythropoietin with a Hydroxyapatite Carrier Administered in Mice

Nagasaki

Ikoma

Katsuda

et al. 2009

The Journal of Veterinary Medical Science

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ABSTRACT. For chronic kidney disease patients with renal anemia, recombinant human erythropoietin (rHuEPO) is a very effective drug; however, the treatment regime is troublesome, requiring multiple administrations each week. In the present study, we examined the efficiency of hydroxyapatite (HAp) as a drug delivery carrier for the sustained release of erythropoietin (EPO) to reduce the frequency of administration. Spray-dried HAp microparticles, formed from zinc-containing HAp (Zn-HAp) and Zn-HAp calcined at 400C, were used as carriers of EPO, and five Zn-HAp formulation samples incorporating EPO were prepared; no formulation, poly-L-lactic acid (PLA) formulation, zinc (Zn) formulation, Zn/PLA formulation, and calcined/Zn/PLA formulation. ICR mice were administered these samples or commercial rHuEPO (Epogin) as a control from dorsal neck subcutaneous, and hematological and histopathological analyses, including enzyme-linked immunosorbent assay for plasma EPO concentration, were performed. An increase in the blood EPO level was detected on days 3 and 8 post-administration. Peak hematopoiesis was delayed and higher hematological values were obtained on day 14 post-administration with no serious adverse reactions compared with the control. The Zn/PLA formulation sample was found to be most effective in reducing the initial peak while sustaining the delayed release of EPO. In conclusion, the Zn-HAp formulation samples were considered to be useful carriers for the sustained release of EPO, and the Zn/PLA formulation appears to be the most effective of five Zn-HAp formulation samples in sustaining EPO release.KEY WORDS: anemia, erythropoietin, hydroxyapatite, sustained release.

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Section: Discussionmentioning

confidence: 99%

Sustained Efficacy of Erythropoietin with a Hydroxyapatite Carrier Administered in Mice

Nagasaki

Ikoma

Katsuda

et al. 2009

The Journal of Veterinary Medical Science

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“…These peaks are ascribed to PLGA 50/50 because it is more amorphous than fucoxanthin. Yamaguchi et al 55 have reported that PLGA in nature is amorphous.…”

Section: Crystallinity Analysis Of Materialsmentioning

confidence: 99%

Fabrication of Fucoxanthin-Loaded Microsphere(F-LM) By Two Steps Double-Emulsion Solvent Evaporation Method and Characterization of Fucoxanthin before and after Microencapsulation

et al. 2016

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“…An example was shown in insulin microencapsulation using the solid in oil in water (s/o/w) emulsion method (Yamaguchi et al, 2002). According to Yamaguchi et al, addition of a small fraction of glycerol into the primary (s/o) suspension enhanced internalization of insulin into the PLGA microparticles, by forming a "mini-emulsion", and suppressed the initial burst from 40% to 10%.…”

Section: Drug Distribution In Microparticlesmentioning

confidence: 99%

Control of encapsulation efficiency and initial burst in polymeric microparticle systems

2004

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Initial burst is one of the major challenges in protein-encapsulated microparticle systems. Since protein release during the initial stage depends mostly on the diffusional escape of the protein, major approaches to prevent the initial burst have focused on efficient encapsulation of the protein within the microparticles. For this reason, control of encapsulation efficiency and the extent of initial burst are based on common formulation parameters. The present article provides a literature review of the formulation parameters that are known to influence the two properties in the emulsion-solvent evaporation/extraction method. Physical and chemical properties of encapsulating polymers, solvent systems, polymer-drug interactions, and properties of the continuous phase are some of the influential variables. Most parameters affect encapsulation efficiency and initial burst by modifying solidification rate of the dispersed phase. In order to prevent many unfavorable events such as pore formation, drug loss, and drug migration that occur while the dispersed phase is in the semi-solid state, it is important to understand and optimize these variables.

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Insulin-loaded biodegradable PLGA microcapsules: initial burst release controlled by hydrophilic additives

Cited by 135 publications

References 19 publications

Sustained Efficacy of Erythropoietin with a Hydroxyapatite Carrier Administered in Mice

Sustained Efficacy of Erythropoietin with a Hydroxyapatite Carrier Administered in Mice

Fabrication of Fucoxanthin-Loaded Microsphere(F-LM) By Two Steps Double-Emulsion Solvent Evaporation Method and Characterization of Fucoxanthin before and after Microencapsulation

Control of encapsulation efficiency and initial burst in polymeric microparticle systems

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