Effect of acidic pH on PLGA microsphere degradation and release

Zolnik, Banu S.; Burgess, Diane J.

doi:10.1016/j.jconrel.2007.05.034

Cited by 463 publications

(309 citation statements)

References 25 publications

Supporting

Mentioning

280

Contrasting

Unclassified

Order By: Relevance

“…Poly (lactic-co-glycolic acid) (PLGA) is a biocompatible, biodegradable polymer [20,21] with a history of over forty years use in medical resorbable sutures [22]. Protein encapsulation by a double emulsion method (water/oil/water) is a well regarded robust technique [23][24][25] with encapsulation efficiencies in the range of 42% to 100% [26][27][28][29].…”

Section: Introductionmentioning

confidence: 99%

PLGA-Based Microparticles for the Sustained Release of BMP-2

et al. 2011

View full text Add to dashboard Cite

Abstract:The development of growth factor delivery strategies to circumvent the burst release phenomenon prevalent in most current systems has driven research towards encapsulating molecules in resorbable polymer matrices. For these polymer release techniques to be efficacious in a clinical setting, several key points need to be addressed. This present study has investigated the encapsulation of the growth factor, BMP-2 within PLGA/PLGA-PEG-PLGA microparticles. Morphology, size distribution, encapsulation efficiency and release kinetics were investigated and we have demonstrated a sustained release of bioactive BMP-2. Furthermore, biocompatibility of the PLGA microparticles was established and released BMP-2 was shown to promote the differentiation of MC3T3-E1 cells towards the osteogenic lineage to a greater extent than osteogenic supplements (as early as day 10 in culture), as determined using alkaline phosphatase and alizarin red assays. This study showcases a potential BMP-2 delivery system which may OPEN ACCESSPolymers 2011, 3 572 now be translated into more complex delivery systems, such as 3D, mechanically robust scaffolds for bone tissue regeneration applications.

show abstract

Section: Introductionmentioning

confidence: 99%

PLGA-Based Microparticles for the Sustained Release of BMP-2

et al. 2011

View full text Add to dashboard Cite

show abstract

“…It is reported that degradation of PLGA is faster at acidic pH than that at neutral pH. 35,36 As PLGA-Glc contains PLGA units, it is expected that it would also show an accelerated degradation at acidic pH. Due to the faster degradation property of PLGA derivatives, drug release seemed to be improved at acidic pH, compared to the neutral pH, in our previous study.…”

Section: In Vitro Dct Releasementioning

confidence: 69%

Poly((D,L)lactic-glycolic)acid–star glucose nanoparticles for glucose transporter and hypoglycemia-mediated tumor targeting

Park¹,

Cho²,

Kim³

2017

IJN

View full text Add to dashboard Cite

Poly((D,L)lactic-glycolic)acid–star glucose (PLGA-Glc) polymer-based nanoparticles (NPs) were fabricated for tumor-targeted delivery of docetaxel (DCT). NPs with an approximate mean diameter of 241 nm, narrow size distribution, negative zeta potential, and spherical shape were prepared. A sustained drug release pattern from the developed NPs was observed for 13 days. Moreover, drug release from PLGA-Glc NPs at acidic pH (endocytic compartments and tumor regions) was significantly improved compared with that observed at physiological pH (normal tissues and organs). DCT-loaded PLGA-Glc NPs (DCT/PLGA-Glc NPs) exhibited an enhanced antiproliferation efficiency rather than DCT-loaded PLGA NPs (DCT/PLGA NPs) in Hep-2 cells, which can be regarded as glucose transporters (GLUTs)-positive cells, at ≥50 ng/mL DCT concentration range. Under glucose-deprived (hypoglycemic) conditions, the cellular uptake efficiency of the PLGA-Glc NPs was higher in Hep-2 cells compared to that observed in PLGA NPs. Cy5.5-loaded NPs were prepared and injected into a Hep-2 tumor-xenografted mouse model for in vivo near-infrared fluorescence imaging. The PLGA-Glc NPs group exhibited higher fluorescence intensity in the tumor region than the PLGA NPs group. These results imply that the PLGA-Glc NPs have active tumor targeting abilities based on interactions with GLUTs and the hypoglycemic conditions in the tumor region. Therefore, the developed PLGA-Glc NPs may represent a promising tumor-targeted delivery system for anticancer drugs.

show abstract

“…42 The final accelerated release phase is explained by the local build-up of lactic and glycolic acid, the PLGA degradation byproducts, which have an auto-catalytic effect on polyester degradation. 43 Eventually the PLGA chains breakdown to a critical state such that the microparticle structure starts to disintegrate. 44 Although the time frame for release in this study was 3 months, the release rates for specific drug applications can be tuned to be shorter or longer by modifying various process parameters during microsphere preparation.…”

Section: Resultsmentioning

confidence: 99%

Design of Protein‐Releasing Chitosan Channels

Kim¹,

Tator²,

Shoichet³

2008

Biotechnology Progress

View full text Add to dashboard Cite

After traumatic injury to the spinal cord, the neural tissue degenerates, resulting in lost function below the site of injury. Promoting axonal regeneration after injury remains a challenge; however, guidance channels have demonstrated some success when combined with cellular and protein therapies. One of the limitations of current guidance channels is the inability to deliver therapeutically relevant molecules in situ, within the guidance channel, to enhance regeneration. In an effort to provide a system for local and sustained drug release, poly(lactide-co-glycolide) (PLGA) microspheres were embedded into chitosan guidance channels by a novel spin-coating technique. The method was designed to create guidance channels with the appropriate dimensions for implantation into the spinal cord, with special attention paid to the wall thickness. The release and bioactivity of a model protein, alkaline phosphatase, was followed from the channels and compared to those from free-floating microspheres over a 90-day period. Since chitosan formulations often require the use of acidic solutions, careful attention was paid to redesign the process to minimize exposure of PLGA microspheres to acid. This was achieved as demonstrated by release and bioactivity data where alkaline phosphatase released from chitosan/microsphere channels followed a profile and bioactivity similar to those of free floating microspheres.

show abstract

Effect of acidic pH on PLGA microsphere degradation and release

Cited by 463 publications

References 25 publications

PLGA-Based Microparticles for the Sustained Release of BMP-2

PLGA-Based Microparticles for the Sustained Release of BMP-2

Poly((D,L)lactic-glycolic)acid–star glucose nanoparticles for glucose transporter and hypoglycemia-mediated tumor targeting

Design of Protein‐Releasing Chitosan Channels

Contact Info

Product

Resources

About

Effect of acidic pH on PLGA microsphere degradation and release

Cited by 463 publications

References 25 publications

PLGA-Based Microparticles for the Sustained Release of BMP-2

PLGA-Based Microparticles for the Sustained Release of BMP-2

Poly((D,L)lactic-glycolic)acid&ndash;star glucose nanoparticles for glucose transporter and hypoglycemia-mediated tumor targeting

Design of Protein‐Releasing Chitosan Channels

Contact Info

Product

Resources

About

Poly((D,L)lactic-glycolic)acid–star glucose nanoparticles for glucose transporter and hypoglycemia-mediated tumor targeting