Drug release from compressed hydrophilic POLYOX-WSR tablets

Area of Science:

• Pharmaceutical Sciences
• Materials Science
• Polymer Chemistry

Background:

• Poly(ethylene oxide) (PEO) is widely used in controlled drug delivery systems.
• Understanding PEO's role in drug release kinetics is crucial for tablet formulation.
• Factors influencing drug release from PEO matrices require detailed investigation.

Purpose of the Study:

• To investigate the influence of PEO molecular weight on drug release from compressed tablets.
• To evaluate the impact of drug loading, solubility, dissolution medium pH, and stirring rate on drug release.
• To elucidate the mechanisms governing drug release kinetics in PEO-based tablets.

Main Methods:

• Preparation of compressed tablets using poly(ethylene oxide) (PEO) of varying molecular weights, a drug, and magnesium stearate.
• In vitro drug release studies under different conditions.
• Analysis of drug release kinetics and correlation with polymer properties (swelling/erosion).

Main Results:

• High molecular weight PEO tablets (2x10^6 and 4x10^6) exhibited anomalous release kinetics, dominated by polymer swelling.
• Low molecular weight PEO tablets (0.9x10^6) demonstrated controlled release, governed by swelling/erosion, leading to constant release rates.
• Drug loading, drug solubility, dissolution medium pH, and stirring rate did not significantly affect drug release, irrespective of PEO molecular weight.

Conclusions:

• PEO molecular weight is a critical determinant of drug release mechanisms and kinetics in compressed tablets.
• Low molecular weight PEO offers predictable and constant drug release, suitable for specific therapeutic applications.
• The formulation parameters investigated (loading, solubility, pH, stirring) have minimal impact compared to PEO molecular weight.