In vitro and in vivo degradation behavior and the long-term performance of biodegradable PLCL balloon implants

Biodegradable poly(l-lactide-co-ε-caprolactone) (PLCL) are used to prepare inflatable balloon implants in treating rotator-cuff injuries and tissue separation. These balloon implants act as a temporary spacer for tissues, while reducing pain and allowing rehabilitation after surgery. It is essential to ensure that each balloon fulfill two requirements after implantation: (1) display a well-defined degradation profile, and (2) remain unaffected by premature rapture or leakage. Storage also affects the stability of a polymer-based implant. Since the balloons are implanted into humans, it is essential to understand their in vitro and in vivo degradation along with their physicochemical properties. It is unpredictable if balloon storage on their performance. Therefore, the in vitro and in vivo degradation behavior of PLCL balloons was examined during one year, and the information obtained was used to correlate reliability under prolonged storage conditions. We investigated changes in weight, melting temperature (T_m), molecular weight distribution (M_w, M_n and PDI), crystallinity (Χ), optical activity [α], and inherent viscosity (η) of the balloons during the entire degradation time. We also examined the molecular properties of the balloons under annealing and extreme temperature conditions, such as the combined effect of temperature and humidity that simulate various storage conditions. We have concluded that degradation of the PLCL balloons is slow, and they remain stable during the test period. Results reveal that the balloons retain their molecular properties under long-term storage, annealing, and extreme temperature conditions. The balloons did not show any variation from reference samples, and they exhibited a constant stability profile even after shelf-storage of more than 3 years. These findings can serve as a case study for evaluating various other biodegradable materials.