Liquid crystalline structure affects drug release from Pluronic® gels

Area of Science:

• Materials Science
• Pharmaceutical Sciences
• Drug Delivery

Background:

• Pluronic® gels loaded with bupivacaine salts (Bup-γL) are used for oral mucositis pain.
• Drug release mechanisms from these Pluronic® gels are not fully understood.
• Understanding release mechanisms is crucial for optimizing Pluronic®-based formulations.

Purpose of the Study:

• To investigate the drug release mechanisms from Pluronic® gels.
• To explore the influence of sodium lauryl sulfate (SLS) on drug release.
• To correlate liquid crystalline structures with drug release kinetics.

Main Methods:

• In vitro release studies of hydrophilic (BupHCl) and hydrophobic (Bup-γL, Bup-L) bupivacaine salts.
• Analysis of Pluronic® gel structures using small-angle X-ray scattering (SAXS).
• Rheological and nano differential scanning calorimetry (nano DSC) analyses of formulations.

Main Results:

• Hydrophobic drug release (Bup-γL, Bup-L) was significantly slower in SLS-induced cubic phases (bcc, fcc) compared to hexagonal phases.
• Hydrophilic drug release (BupHCl) showed no significant difference between SLS-induced lamellar and hexagonal phases.
• Liquid crystalline structure significantly impacted hydrophobic drug release but not hydrophilic drug release.

Conclusions:

• Liquid crystalline structure dictates drug release behavior in Pluronic® gels, particularly for hydrophobic drugs.
• Findings provide insight into bupivacaine salt release mechanisms for oral mucositis pain control.
• Results offer valuable guidance for designing future Pluronic®-based drug delivery systems for controlled release.