Development and evaluation of sustained-release propranolol wax microspheres

Area of Science:

• Pharmaceutical Technology
• Drug Delivery Systems
• Materials Science

Background:

• Gastrointestinal side effects are common with immediate-release propranolol formulations.
• Sustained-release systems aim to improve therapeutic efficacy and patient compliance.
• Microsphere technology offers potential for controlled drug release and targeted delivery.

Purpose of the Study:

• To develop wax microspheres of propranolol using congealable dispersion microencapsulation.
• To investigate the impact of various process variables on microsphere characteristics.
• To achieve a sustained-release dosage form with reduced gastric irritation.

Main Methods:

• Congealable dispersion microencapsulation technique was employed.
• Factorial design was used to study process variables: wax type, emulsification speed, drug loading, and emulsifier type/amount.
• In-vitro drug release, entrapment efficiency, particle size, angle of repose, and dissolution efficiency were evaluated.

Main Results:

• Wax type, emulsifier concentration, and type significantly affected entrapment efficiency.
• All studied variables influenced microsphere angle of repose and particle size.
• Wax type was the primary factor affecting dissolution efficiency.
• Drug release at pH 6.8 was influenced by all variables except emulsifier amount.
• An optimized formulation (0.25:4 drug:ceresine wax, 0.04% Tween 80, 600 rpm) showed promising retarded dissolution.

Conclusions:

• Wax microspheres provide a viable strategy for sustained-release propranolol delivery.
• Process optimization is crucial for controlling microsphere properties and drug release kinetics.
• The developed system facilitates intestinal absorption, potentially reducing gastric adverse effects.