Polyanhydrides: Synthesis, Properties, and Applications

Abstract

This review focusses on polyanhydrides, a fascinating class of degradable polymers that have been used in and investigated for many bio-related applications because of their degradability and capacity to undergo surface erosion. This latter phenomenon is driven by hydrolysis of the anhydride moieties at the surface and high hydrophobicity of the polymer such that degradation and mass loss (erosion) occur before water can penetrate deep within the bulk of the polymer. As such, when surface-eroding polymers are used as therapeutic delivery vehicles, the rate of delivery is often controlled by the rate of polymer erosion, providing predictable and controlled release rates that are often zero-order. These desirable attributes are heavily influenced by polymer composition and morphology, and therefore also monomer structure and polymerization method. This review examines approaches for polyanhydride synthesis, discusses their general thermomechanical properties, surveys their hydrolysis and degradation processes along with their biocompatibility, and looks at recent developments and uses of polyanhydrides in drug delivery, stimuli-responsive materials, and novel nanotechnologies.

Polymer-based drug delivery systems for cancer treatment

“…Polyanhydrides, generally consist of poly(sebacic acid), poly(adipic acid), and poly(terphthalic acid), have been used in various biomedical applications due to their degradability and capability to undergo surface erosion . Driven by hydrolysis of the anhydride moieties at the surface and high hydrophobicity of the polymer, degradation and mass loss (erosion) occur prior to water penetrating deep within the bulk of the polymer . In this case, drug release kinetics is dependent on properties of the cargo and intrinsic dissolution rates.…”

“…The degradation of polyanhydrides is the main factor in release of a hydrophobic drug, whereas for a hydrophilic drug, the concentration gradient between the vehicle and surrounding medium affects the solute transport . In addition to acidic or alkaline conditions, polyanhydrides readily degrade in neutral aqueous environment, causing a much shorter average half‐life when compared with other hydrolytically degradable polymers such as polyesters and polyamides . Therefore, polyanhydrides have excellent potentials as carriers for the sustained release of therapeutics.…”

“…Owing to the reactivity of the anhydride group towards nucleophilic species, especially water, the synthesis of polyanhydrides is quite challenging. In addition to polycondensation of dicarboxylic acid monomers, other synthetic strategies have been developed to generate polyanhydrides, including radical polymerization of methacrylated anhydride monomers and acyclic diene metathesis (ADMET) and radical‐mediated thiolene polymerization . However, there are disadvantages to each of the polymerization methods and monomer types for polyanhydride synthesis.…”

Estudo sobre a utilização de polianidrido como abordagem terapêutica para o tratamento de lesões no tecido ósseo

“…Os copolímeros são cadeias poliméricas que vão possuir duas ou mais unidades monoméricas, podendo ser classificados em: alternados, aleatórios, em blocos, de enxertos e etc., podendo ser ajustados de acordo com a sua aplicação, como é o caso dos copolimeros de anidridos, que são utilizados para aperfeiçoar suas propriedades mecânicas, sendo que os polianidridos se degradam muito rapidamente e, para manter o controle da taxa de degradação, os componentes hidrofílicos e hidrofóbicos sofrem alteração (Cimatu, Premadasa, Ambagaspitiya, Adhikari, & Jang, 2020;Poetz & Shipp, 2016). Eles têm sido utilizados como transportadores para a distribuição controlada de medicamentos.…”

“…Eles têm sido utilizados como transportadores para a distribuição controlada de medicamentos. Os copolímeros são fáceis e baratos de sintetizar, além disso os copolimeros de polianidridos apresentam uma vida útil curta por causa da clivagem hidrolítica, possuem quimica anfifílica, sofrem erosão superficial, produtos de degradação menos ácidos e as trocas de anidrido que diminuem seus pesos moleculares durante o armazenamento (Basu & Domb, 2018;Liu et al, 2020;Poetz & Shipp, 2016).…”