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Biodegradable Polymers: Two EKG Labs Case Studies

Biodegradable/bioabsorbable polymers degrade in vivo to biocompatible and toxicologically safe by-products that are removed via normal metabolic pathways. These polymers are used in implanted medical devices whose purpose is to provide a physical structure to assist healing and/or to act as a delivery mechanism for a therapeutic purpose. EKG leverages our knowledge of material compatibilityextractables & leachables, and ISO 10993-18 chemical characterization to help clients submit biodegradable polymers for regulatory approval.

PLGA Case Study

Poly(lactic-co-glycolic acid), or PLGA, is a copolymer approved by the FDA for a variety of medical devices, such as prosthetics, implants, grafts, sutures, or other wound care and tissue engineering functionality. More recently, PLGA has also been investigated in micro and nanoparticle targeted drug delivery. PLGA is an ideal polymer for therapeutic purposes as it is readily biodegradable and inherently biocompatible, breaking down into glycolic acid and lactic acid, two monomers that are by-products of other body processes and that have established metabolic pathways. Many forms of PLGA can be synthesized to optimize degradation for specific purposes, such as sustained drug delivery.

EKG Labs has been working on a GPC (gel permeation chromatography) study on a unique PLGA composition. GPC is a type of size-exclusion chromatography that is able to separate polymers by molecular weight and determine their distribution. The goal of this study has been to use GPC analysis to assess this polymer’s molecular weight distribution change over time. The study involves incubating the polymer at a variety of temperatures and in a variety of buffers, in order to simulate how the polymer would break down in targeted locations within the human body. This study will allow our client to have a better sense of the degradation expected within their clinical trials.

graph of average PLGA molecular weights

Graph of average PLGA molecular weights versus days of degradation in phosphate-buffered saline at 37°C.

Hydrogel Case Study

Hydrogels are hydrophilic polymers with a vast array of applications, including tissue engineering scaffolds, injectable hydrogels as drug or cell carriers, sustained-release drug delivery systems, implants, and wound-healing gels.

Recently, EKG performed a full-scale extractable and leachable study on hydrogels according to the guidance of ISO 10993-18 chemical characterization. After performing an initial exhaustive extractable study, we then performed a leachable study in tandem with a simulated degradation study. After noting a compound consistently leaching from the gels, we worked to successfully identify and characterize the impurity which turned out to be a manufacturing residual from the polymer production.

hydrogels

Hydrogels post extraction in a variety of solvents.

For more on biodegradable polymer analytical services at EKG Labs, visit our bioabsorbable polymer webpage.

About EKG Labs

EKG Labs is an analytical service provider for the pharmaceutical and medical device industries. Our wide variety of analytical services support product development, regulatory filings, and analytical chemistry investigations. You can contact EKG Labs at info@ekglabs.com or at 810-354-5229.