Diffusion and binding of 5-fluorouracil in non-ionic hydrogels with interpolymer complexation

Area of Science:

• Polymer Science
• Materials Science
• Drug Delivery

Background:

• Hydrogen-bonded interpolymer complexes offer unique properties for novel dosage forms.
• Crosslinked hydrogels, including copolymer networks and interpenetrating polymer networks (IPN), can be designed using polymers like N-vinyl pyrrolidone and acrylamide (PVP-co-PAM) and poly(vinyl alcohol) (PVA).
• Non-ionic complexes formed through H-bonding act as additional crosslinks, influencing hydrogel properties.

Purpose of the Study:

• To synthesize and characterize two types of crosslinked hydrogels: PVP-co-PAM and IPNs of PVP-co-PAM/PVA.
• To investigate the effect of varying crosslinking degrees on hydrogel swelling, permeability, and drug binding.
• To explore the drug release kinetics and transport mechanisms of 5-fluorouracil (5-FU) from these hydrogel systems.

Main Methods:

• Synthesis of crosslinked PVP-co-PAM copolymer networks and PVP-co-PAM/PVA interpenetrating polymer networks (IPNs) at three different crosslinking densities.
• Swelling studies to determine hydrogel sensitivity.
• Permeability measurements to assess pore structure.
• Fourier transform infrared (FTIR) difference spectroscopy to probe drug-polymer interactions.
• Drug release studies analyzed using the Peppas model.

Main Results:

• Both hydrogel types exhibited significantly higher swelling sensitivity compared to ionizable hydrogels.
• IPNs showed increased permeability with PVA incorporation, indicating more open pores, which decreased with higher crosslinking density.
• FTIR analysis confirmed substantial hydrogen bonding between 5-FU and polymer side chains.
• Drug binding interactions were stronger in PVP-co-PAM copolymers than in IPNs.
• Both hydrogel systems demonstrated non-Fickian drug release kinetics, with slower release observed in copolymer hydrogels due to stronger drug-polymer interactions.

Conclusions:

• Synthesized hydrogels possess tunable swelling and permeability properties influenced by crosslinking degree and composition.
• Significant hydrogen bonding interactions between 5-FU and polymers contribute to controlled drug release.
• These hydrogen-bonded interpolymer complexes represent promising materials for developing advanced drug delivery systems with tailored release profiles.