In Vivo Degradation Mechanism and Biocompatibility of a Biodegradable Aliphatic Polycarbonate: Poly(Trimethylene Carbonate-co-5-Hydroxy Trimethylene Carbonate)

Abstract

A recently developed viscous liquid aliphatic polycarbonate, poly­(trimethylene carbonate-co-5-hydroxy trimethylene carbonate), has advantageous properties for the delivery of acid-sensitive drugs such as proteins and peptides. This copolymer degrades in vitro via an alkaline-catalyzed intramolecular cyclization reaction yielding oligo (trimethylene carbonate), glycerol, and carbon dioxide, but its in vivo degradation mechanisms are presently unknown. The in vivo degradation mechanism and tissue response to this copolymer were investigated following subcutaneous implantation in Wistar rats. The molecular weight and composition of the copolymer varied in the same manner following subcutaneous implantation as observed in vitro. These findings suggest that the copolymer also degraded in vivo principally via intramolecular cyclization. The tissue response in terms of the inflammatory zone cell density, fibrous capsule thickness, and macrophage response was intermediate to that of two clinically used biodegradable sutures, Vicryl and Monocryl, indicating that the copolymer can be considered biotolerable. Collectively, the data show that further development of this copolymer as a drug delivery material is warranted.

Long-Term Vaccine Delivery and Immunological Responses Using Biodegradable Polymer-Based Carriers

“…In stimuli-sensitive systems, various stimuli such as temperature, pH, ionic strength, ultrasound, electricity, or magnetic fields can lead to controlled release by an externally controlled mechanism (E). Drug release through the degradation of polymer systems occurs on the polymer’s surface (F1) or inside the polymer by backbone cleavage, side-chain cleavage, or cross-link cleavage (F2) …”

“…Drug release through the degradation of polymer systems occurs on the polymer's surface (F1) or inside the polymer by backbone cleavage, sidechain cleavage, or cross-link cleavage (F2). 66 According to the types of cargo release processes that were mentioned in the previous paragraph, the release of polymer systems is influenced by several factors such as intrinsic properties of polymer including crystallinity, size, and type of carrier design, selected cargo, and the affinity of cargo and carrier, as well as the presence of external stimuli in the environment related to the host species. For this reason, the release mechanism can simultaneously be a combination of different processes such as permeation, penetration through polymer degradation, polymer erosion, swelling, etc.…”

Carbonate-Terminated Self-Assembled Monolayers for Mimicking Nanoscale Polycarbonate Surfaces

“…In 1969, Inoue et al pioneered the synthesis of polycarbonates from carbon dioxide, one of the main greenhouse gases . Since then, PC materials have received considerable attention in various industries due to their toughness, light weight, optical transparency, and biocompatibility. − In addition, the slow rates of biodegradation of PC materials to non-acidic products compared to other biocompatible polymers (e.g., polyesters, polylactides, and polycaprolactones) make them promising polymer coatings for bioactive materials and applications. , …”

Overview: Polycarbonates via Ring-Opening Polymerization, Differences between Six- and Five-Membered Cyclic Carbonates: Inspiration for Green Alternatives

“…PCs have attracted the most attention over the past two decades for their significant potential in environmental and biomedical applications [ 6 ] due to their biocompatibility, biodegradability, bioresorbable activity [ 7 ], and the weak inflammatory properties of the degraded products [ 8 , 9 ]. There are several important biomedical uses of biodegradable polymers, some of which are listed below: Packaging is potentially the largest use of biodegradable polymers [ 10 ].…”