Correlating in vitro degradation and drug release kinetics of biopolymer-based drug delivery systems

Abstract

Polymers are becoming more important in all economic sectors, and as environmental concerns grow, biopolymers are replacing metal-or oil-based polymers. Two of these polymers are polyhydroxybutyrate (PHB), which is known for good mechanical characteristics and the manufacturing from renewable resources, and polylactic acid (PLA), which is known for fast degradation rates and great benefits for packaging industry. They exhibit properties that make them competitive alternatives for the less eco-friendly polymers, but processing techniques are not as well-researched. In this study, we performed in vitro degradation and drug release studies with pure PHB and PLA and PHB/PLA blends (1:3). Therefore, polymers were stored at 65°C in a PBS-buffer under rather static conditions to simulate intraossal localization. The mass loss of all samples indicates a degradation of all polymers, and it was confirmed by decreasing molecular weight, decreasing pH, increasing crystallinity, and decreasing water contact angle. Following these measurements, a 60-day drug release study was performed, which revealed a four-phase drug release mechanism, including a diffusion-controlled initial burst release especially elevated for investigated blends due to eased medium interpenetration, and a secondary burst release after 20 days for both blends and the pure PLLA-Biomer with lower molecular weight. The intensity of the secondary burst release corresponded to observed degradation characteristics allowing the conclusion of a degradation controlled drug release here.

New Water-Soluble Oxyamino Chitosans as Biocompatible Vectors for Efficacious Anticancer Therapy via Co-Delivery of Gene and Drug

“…In the case of intratumoral injections, as performed herein, the initial burst release is an important contributor to efficient tumor regression. 64 Additionally, the minor drug release (<20%) at pH 7.4 does not affect the study due to direct injection mode employed herein in the vicinity of the tumor especially where the acidic pH prevails around the tumorous microenvironment.…”

Effect of nitrogen limitation on polyhydroxyalkanoates production efficiency, properties and microbial dynamics using a soil-derived mixed continuous culture

“…the case of polylactide/PLA) or (c) entirely microbial processes (i.e. the case of poly-hydroxyalkanoates/PHAs) [2]. The latter is of great interest nowadays due to the unique properties of the resulting polymers.…”

Development of a smart pH-responsive nano-polymer drug, 2-methoxy-4-vinylphenol conjugate against the intestinal pathogen, Vibrio cholerae

“…The complete release of the 2M4VP from CAP nano-formulation was observed at pH 7.0 at 40th h. However, a burst release of about 51% was observed at pH 7.0, indicating a release triggered by diffusion and release of drugs near the surface of the nanoparticles. The slow linear release noted after that could have been caused by the diffusion of 2M4VP from the bulk of the nanoparticle 38 . Controlled drug releases were observed in all media of various pH included in this study, indicating the possibility of achieving a targeted release of drug 2M4VP in a controlled manner.…”