Development and evaluation of controlled-release diclofenac microspheres and tabletted microspheres

Area of Science:

• Pharmaceutical Technology
• Drug Delivery Systems
• Materials Science

Background:

• Diclofenac is a widely used non-steroidal anti-inflammatory drug (NSAID).
• Effective drug delivery systems are crucial for optimizing therapeutic outcomes and minimizing side effects.
• Microsphere technology offers potential for controlled and sustained drug release.

Purpose of the Study:

• To prepare and characterize diclofenac wax microspheres using the congealable disperse phase encapsulation method.
• To investigate the influence of emulsifiers (glyceryl monostearate and stearic acid) on microsphere properties and drug release.
• To evaluate the tableting properties and dissolution behavior of diclofenac wax microspheres.

Main Methods:

• Congealable disperse phase encapsulation method for diclofenac wax microspheres.
• Incorporation of glyceryl monostearate (GMS) and stearic acid as emulsifiers.
• Analysis of drug content, particle size distribution, and drug release kinetics (Higuchi/Baker Londsdale model).
• Preparation and evaluation of disintegrating tableted microspheres using Avicel and Explotab.

Main Results:

• Microspheres exhibited high drug content (80-90%) and log-normal particle size distribution.
• GMS decreased drug release, while stearic acid enhanced it; combined emulsifiers modulated release.
• Increased dispersant (PVP) concentration and decreased microsphere size accelerated drug release.
• Tableting increased crushing force and disintegration time but did not significantly affect dissolution profiles.
• Higher microsphere loading in tablets increased disintegration time and introduced a lag time in dissolution.

Conclusions:

• Emulsifier selection and concentration are critical for controlling diclofenac release from wax microspheres.
• Diclofenac wax microspheres can be formulated into disintegrating tablets with tunable release characteristics.
• The developed microspheres show promise for sustained delivery of diclofenac.