Effect of polymers on dissolution from drug suspensions.

Area of Science:

• Pharmaceutical Sciences
• Physical Chemistry

Background:

• Nitrofurantoin is a widely used antibiotic.
• Understanding drug release from suspensions is crucial for formulation development.

Purpose of the Study:

• To investigate the impact of methylcellulose viscosity on nitrofurantoin dissolution-dialysis rates.
• To characterize the influence of methylcellulose on drug release kinetics.

Main Methods:

• Utilized a specialized dialysis cell with a large surface area.
• Measured apparent dialytic rate constants for nitrofurantoin solutions and suspensions.
• Tested formulations in 0.1 N HCl and pH 7.4 buffer.

Main Results:

• Methylcellulose reduced nitrofurantoin's dialysis rate, especially when used as a suspending agent.
• Observed lower rates attributed to methylcellulose-drug complexation and localized high viscosity.
• Developed an empirical relationship to estimate effective drug concentration in dispersions.

Conclusions:

• Methylcellulose viscosity grades influence nitrofurantoin release from suspensions.
• The findings provide insights into drug-polymer interactions affecting dissolution.
• The developed method aids in comparing suspension formulation performance.