The efficacy of hydrogel foams in talc Pleurodesis

Abstract

Background: Malignant pleural effusions are a serious complication of many late stage cancers that adversely affect quality of life. Pleurodesis with talc slurry is a standard treatment option, but clinical failures occur, possible due to poor talc delivery. A novel drug-delivery system was developed that fills the entire thoracic cavity with a liquid foam containing talc. The foam is designed to gel and adhere to the tissue walls at body temperature, to improve talc deposition and efficacy. Methods: Rheology, foam stability, and ex-vivo coating and bio-adhesion studies were performed on three concentrations of a novel hydrogel talc foam system that was developed to improve delivery of talc to the pleural surfaces. A New Zealand rabbit model of pleurodesis was used to evaluate effectiveness of the foams at inducing adhesion formation and compared to talc slurry. The rabbits were recovered after they had one of the test agents instilled into their pleura, and then sacrificed after 28 days. Pleurodesis was assessed by a blinded pathologist using a standardized pathological scoring system. Results: All talc foam formulations produced foams that gelled at physiological temperatures and were relatively stable for at least two hours. As the concentration of the formulation increased the gelation temperature decreased and the foam adhesiveness increased. Rabbits that received talc foam had significantly greater adhesion formation than talc slurry (mean score of 2.21 vs. 1.18 (p < 0.05)). Rabbits that received the 20% foam developed the most adhesions.Conclusions: This study demonstrates that our triblock copolymer hydrogel foam delivery system enhances adhesion formation in an experimental model. This novel approach can have important clinical impact, potentially improving efficacy of existing therapies and reducing the need for more invasive treatments.

One-Step Generation of Alginate-Based Hydrogel Foams Using CO2 for Simultaneous Foaming and Gelation

“…Hydrogel foams are very attractive for biomedical [ 1 , 2 , 3 , 4 , 5 ], cosmetic [ 6 ], food [ 7 ], and agricultural applications [ 8 ] thanks to their absorption capacity, low density, large surface-to-volume ratio, biocompatibility, and mechanical properties. Since they are obtained by the gelling of an initially liquid foam via a method called “liquid foam templating” [ 9 , 10 , 11 ], a reliable foam generation process requires the fine-tuning of a wide range of interrelated timescales: foaming time, gelation time, and foam ageing time.…”