Lactitol-based poly(ether polyol) hydrogels for controlled release chemical and drug delivery systems

Area of Science:

• Polymer Chemistry
• Materials Science
• Biomedical Engineering

Background:

• Lactitol, a sugar alcohol, was chemically modified to create a novel poly(ether polyol) (LPEP).
• Hydroxyl groups in LPEP exhibit an average pK(a) of 1.63.
• This polyol serves as a base for synthesizing advanced hydrogel materials.

Purpose of the Study:

• To synthesize cross-linked hydrogels using LPEP and chlorinated poly(ethylene glycol) bis(carboxymethyl) ether (PEGBCOCl).
• To investigate the swelling behavior of these hydrogels in response to varying cross-linking densities, temperature, salt, glucose, and pH.
• To evaluate the release kinetics of a model active agent (acetylsalicylic acid) and assess the impact of cross-linking on drug diffusivity.

Main Methods:

• Propoxylation of lactitol to form poly(ether polyol) (LPEP).
• Esterification of LPEP with PEGBCOCl to create cross-linked hydrogels.
• Swelling ratio measurements under varied conditions (cross-linking ratio, temperature, salt, glucose, pH).
• Drug release studies using acetylsalicylic acid and analysis of release kinetics and diffusivity.

Main Results:

• Hydrogel swelling decreased with increased cross-linking ratio (PEGBCOCl:LPEP from 2:1 to 4:1).
• Swelling demonstrated sensitivity to temperature (25-55°C) and concentrations of salt and glucose, but not significantly to pH (4-9).
• Drug release followed a half-order time dependence, with diffusivity inversely proportional to cross-linking density.

Conclusions:

• LPEP-based hydrogels exhibit tunable swelling properties influenced by external stimuli.
• The cross-linking ratio effectively controls the release rate of active agents.
• These hydrogels show potential for controlled drug and agrochemical delivery applications.