Physico-mechanical characterization of the extrusion-spheronization process. Part II: Rheological determinants for...

Area of Science:

• Pharmaceutical Technology
• Materials Science

Background:

• Multiparticulate drug delivery systems frequently utilize spheres.
• Extrusion and spheronization are common manufacturing processes for these spheres.
• A fundamental understanding of the rheological and mechanical properties influencing these processes is lacking.

Purpose of the Study:

• To investigate the rheological and mechanical properties of wet masses critical for extrusion and spheronization.
• To identify formulation attributes that govern the success of both processes.
• To establish a predictive model for optimizing sphere production.

Main Methods:

• Developed methods to measure wet mass rheology and mechanical properties (plastic yield value, tensile strength).
• Utilized a model formulation system (microcrystalline cellulose, lactose, hydroxypropylmethylcellulose).
• Employed a Box-Behnken experimental design to correlate formulation variables with process outcomes.

Main Results:

• Identified a critical range of rheological/mechanical variables for successful pellet production.
• Determined that screen pressure significantly impacts yield, while yield value and tensile strength influence sphericity.
• Defined a specific "window" of properties enabling successful extrusion and spheronization.

Conclusions:

• Rheological and mechanical properties of the wet mass are crucial for successful sphere manufacturing.
• Specific critical parameters exist for both extrusion and spheronization.
• Defining this operational "window" allows for optimized design of multiparticulate drug delivery systems.