Effect of physical ageing on the performance of dexamethasone loaded PLGA microspheres

Rawat, Archana; Burgess, Diane J.

doi:10.1016/j.ijpharm.2011.05.067

Cited by 24 publications

(9 citation statements)

References 11 publications

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“…2D and F) and no agglomerate was observed. The PLGA microsphere/PVA hydrogel composites showed a slightly lower initial burst release compared to the PLGA microspheres alone reported previously (Rawat and Burgess, 2011a). It is known that the initial burst release is controlled by diffusion, while the secondary zero-order release phase is governed by polymer erosion as well as diffusion (Faisant et al, 2002; Zolnik et al, 2006).…”

Section: Resultsmentioning

confidence: 44%

Accelerated in vitro release testing of implantable PLGA microsphere/PVA hydrogel composite coatings

Shen

Burgess

2012

International Journal of Pharmaceutics

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Dexamethasone loaded poly(lactic-co-glycolic acid) (PLGA) microsphere/PVA hydrogel composites have been investigated as an outer drug-eluting coating for implantable devices such as glucose sensors to counter negative tissue responses to implants. The objective of this study was to develop a discriminatory, accelerated in vitro release testing method for this drug-eluting coating using United States Pharmacopeia (USP) apparatus 4. Polymer degradation and drug release kinetics were investigated under “real-time” and accelerated conditions (i.e. extreme pH, hydro-alcoholic solutions and elevated temperatures). Compared to “real-time” conditions, the initial burst and lag phases were similar using hydro-alcoholic solutions and extreme pH conditions, while the secondary apparent zero-order release phase was slightly accelerated. Elevated temperatures resulted in a significant acceleration of dexamethasone release. The accelerated release data were able to predict “real-time” release when applying the Arrhenius equation. Microsphere batches with faster and slower release profiles were investigated under “real-time” and elevated temperature (60°C) conditions to determine the discriminatory ability of the method. The results demonstrated both the feasibility and the discriminatory ability of this USP apparatus 4 method for in vitro release testing of drug loaded PLGA microsphere/PVA hydrogel composites. This method may be appropriate for similar drug/device combination products and drug delivery systems.

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Section: Resultsmentioning

confidence: 44%

Accelerated in vitro release testing of implantable PLGA microsphere/PVA hydrogel composite coatings

Shen

Burgess

2012

International Journal of Pharmaceutics

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“…Considering that PLGA manufacturers are not required to provide the sequence information or Mw distribution of the polymer, however, must disclose the Mw (expressed in terms of viscosity of the polymer), the Mw distribution can be determined using gel permeation chromatography (GPC), multi-angle light scattering (MALS), intrinsic viscosity, or osmotic pressure. Of these platforms, only the GPC method can directly detect Mw distribution, making it the most commonly employed method (Rawat & Burgess, 2011). The Mw of PLGA in microspheres may be affected by the manufacturing process.…”

Section: Molecular Weightmentioning

confidence: 99%

Poly(lactic-co-glycolic acid) microsphere production based on quality by design: a review

Hua¹,

Su²,

Zhang³

et al. 2021

Drug Delivery

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Poly(lactic-co-glycolic acid) (PLGA) has garnered increasing attention as a candidate drug delivery polymer owing to its favorable properties, including its excellent biocompatibility, biodegradability, nontoxicity, non-immunogenicity, and mechanical strength. PLAG are specifically used as microspheres for the sustained/controlled and targeted delivery of hydrophilic or hydrophobic drugs, as well as biological therapeutic macromolecules, including peptide and protein drugs. PLGAs with different molecular weights, lactic acid (LA)/glycolic acid (GA) ratios, and end groups exhibit unique release characteristics, which is beneficial for obtaining diverse therapeutic effects. This review aims to analyze the composition of PLGA microspheres, and understand the manufacturing process involved in their production, from a quality by design perspective. Additionally, the key factors affecting PLGA microsphere development are explored as well as the principles involved in the synthesis and degradation of PLGA and its interaction with active drugs. Further, the effects elicited by microcosmic conditions on PLGA macroscopic properties, are analyzed. These conditions include variations in the organic phase (organic solvent, PLGA, and drug concentration), continuous phase (emulsifying ability), emulsifying stage (organic phase and continuous phase interaction, homogenization parameters), and solidification process (relationship between solvent volatilization rate and curing conditions). The challenges in achieving consistency between batches during manufacturing are addressed, and continuous production is discussed as a potential solution. Finally, potential critical quality attributes are introduced, which may facilitate the optimization of process parameters.

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“…Development of biocompatible coatings to reduce biofouling as well as other negative tissue responses such as inflammation and fibrosis (Frost and Meyerhoff 2006; Norton, Koschwanez et al 2007; Bhardwaj, Sura et al 2010; Morais, Papadimitrakopoulos et al 2010; Rawat and Burgess 2011),…”

Section: Introductionmentioning

confidence: 99%

A miniaturized transcutaneous system for continuous glucose monitoring

Croce

Vaddiraju

Kondo

et al. 2012

Biomed Microdevices

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Implantable sensors for continuous glucose monitoring hold great potential for optimal diabetes management. This is often undermined by a variety of issues associated with: (1) negative tissue response; (2) poor sensor performance; and (3) lack of device miniaturization needed to reduce implantation trauma. Herein, we report our initial results towards constructing an implantable device that simultaneously address all three aforementioned issues. In terms of device miniaturization, a highly miniaturized CMOS (complementary metal-oxide-semiconductor) potentiostat and signal processing unit was employed (with a combined area of 0.665 mm2). The signal processing unit converts the current generated by a transcutaneous, Clark-type amperometric sensor to output frequency in a linear fashion. The Clark-type amperometric sensor employs stratification of five functional layers to attain a well-balanced mass transfer which in turn yields a linear sensor response from 0 to 25 mM of glucose concentration, well beyond the physiologically observed (2 to 22 mM) range. In addition, it is coated with a thick polyvinyl alcohol (PVA) hydrogel with embedded poly(lactic-co-glycolic acid) (PLGA) microspheres intended to provide continuous, localized delivery of dexamethasone to suppress inflammation and fibrosis. In vivo evaluation in rat model has shown that the transcutaneous sensor system reproducibly tracks repeated glycemic events. Clarke’s error grid analysis on the as –obtained glycemic data has indicated that all of the measured glucose readings fell in the desired Zones A & B and none fell in the erroneous Zones C, D and E. Such reproducible operation of the transcutaneous sensor system, together with low power (140 μW) consumption and capability for current-to-frequency conversion renders this a versatile platform for continuous glucose monitoring and other biomedical sensing devices.

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Effect of physical ageing on the performance of dexamethasone loaded PLGA microspheres

Cited by 24 publications

References 11 publications

Accelerated in vitro release testing of implantable PLGA microsphere/PVA hydrogel composite coatings

Accelerated in vitro release testing of implantable PLGA microsphere/PVA hydrogel composite coatings

Poly(lactic-co-glycolic acid) microsphere production based on quality by design: a review

A miniaturized transcutaneous system for continuous glucose monitoring

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