PLGA from PolySciTech used in development of acidity control methodology for in-situ implants

 

As PLGA hydrolyzes, the products from this reaction are lactic and glycolic acid. Although these are relatively weak acids, they can contribute to the formation of a low pH (acidity formation) in the local environment which can both lead to inflammation as well as damage biological active pharmaceutics such as protein-based drugs. Researchers at Purdue University used PLGA (Cat# AP041) from PolySciTech Division of Akina, Inc. (www.polyscitech.com) to formulate in-situ forming implants and used these to investigate localized pH reduction due to PLGA degradation as well as develop methods to mitigate this effect using alkaline salts. This research holds promise to enable the use of PLGA for delivery of sensitive, protein-based drugs without damaging the APIs. Read more: Hopkins, Kelsey, Elizabeth Wakelin, Natalie Romick, Jacqueline Kennedy, Emma Simmons, and Luis Solorio. "Basic Salt Additives Modulate the Acidic Microenvironment Around In Situ Forming Implants." Annals of Biomedical Engineering (2022): 1-11. https://link.springer.com/article/10.1007/s10439-022-03109-6

“Abstract: There is a growing number of protein drugs, yet their limited oral bioavailability requires that patients receive frequent, high dose injections. In situ forming implants (ISFIs) for controlled release of biotherapeutics have the potential to greatly reduce the injection frequency and improve patient compliance. However, protein release from ISFIs is a challenge due to their proclivity for instability. Specifically, factors such as the acidic microclimate within ISFIs can lead to protein aggregation and denaturation. Basic salts have been shown in PLGA microparticle and microcylinder formulations to significantly reduce protein instability by neutralizing this acidic environment. The overall objective of the study was to demonstrate that basic salts can be used with an ISFI system to neutralize the implant acidification. To this end, the basic salts MgCO3 and Mg(OH)2 were added to a protein-releasing ISFI and the effect on drug release, pH, implant swelling, implant diffusivity, and implant erosion were evaluated. Either salt added at 3 wt% neutralized the acidic environment surrounding the implants, keeping the pH at 6.64 ± 0.03 (MgCO3) and 6.46 ± 0.11 (Mg(OH)2) after 28 day compared to 3.72 ± 0.05 with no salts added. The salts initially increased solution uptake into the implants but delayed implant degradation and erosion. The 3 wt% Mg(OH)2 formulation also showed slightly improved drug release with a lower burst and increased slope. We showed that salt additives can be an effective way to modulate the pH in the ISFI environment, which can improve protein stability and ultimately improve the capacity of ISFIs for delivering pH-sensitive biomolecules. Such a platform represents a low-cost method of improving overall patient compliance and reducing the overall healthcare burden.”