Poly(N-isopropylacrylamide) copolymers for constant temperature controlled drug delivery

Area of Science:

• Polymer Chemistry
• Materials Science
• Pharmaceutical Sciences

Background:

• Development of novel drug delivery systems is crucial for improving therapeutic efficacy.
• Thermosensitive polymers offer potential for time-controlled drug release.
• Poly(N-isopropylacrylamide) (PNIPAAm) exhibits a lower critical solution temperature near physiological conditions.

Purpose of the Study:

• To synthesize and evaluate thermosensitive PNIPAAm-based copolymers for time-controlled drug delivery.
• To investigate the effect of sodium sulfate (Na2SO4) on drug release kinetics from coated tablets.
• To optimize lag time for drug release using a salting-out effect.

Main Methods:

• Synthesis of four thermosensitive PNIPAAm copolymers with phase transition temperatures slightly above 37°C.
• Preparation of compression-coated tablets incorporating Na2SO4 and coated with thermosensitive copolymers.
• In vitro dissolution testing at a constant physiological temperature to measure drug release profiles.

Main Results:

• Thermosensitive copolymers were successfully synthesized for drug delivery applications.
• The incorporation of Na2SO4 into the tablets significantly increased the lag time before drug release.
• A lag time increase of 80-90% was observed for tablets coated with PNIPAAm-co-NVA and PNIPAAm-co-MVA due to the salting out effect.

Conclusions:

• Thermosensitive PNIPAAm copolymers are effective for developing time-controlled drug delivery systems.
• Sodium sulfate incorporation enhances the time-controlled release by modulating polymer swelling and drug diffusion.
• This approach offers a promising strategy for precise control over drug release timing in pharmaceutical formulations.