Mechanical properties of excipients do not affect polymer matrix formation

Area of Science:

• Pharmaceutical Technology
• Materials Science
• Drug Delivery

Background:

• Polymer particle coalescence is vital for film formation in solid dosage forms.
• The driving forces behind polymer matrix formation during tablet manufacturing are not well understood.
• Investigating the role of mechanical stresses in tablet compression is crucial for optimizing drug release.

Purpose of the Study:

• To determine if compression-induced excipient deformation stresses contribute to polymer matrix formation in tablets.
• To explore the interplay between excipient mechanical properties, polymer content, compression pressure, and thermal treatment on tablet characteristics.

Main Methods:

• Direct compression of polymer matrix tablets with varying Eudragit-RLPO (10% and 40%) and diluent (lactose or mannitol) levels.
• Tablets were compressed at high (221 MPa) and low (74 MPa) pressures and thermally treated at 40°C (below Tg) and 70°C (above Tg).
• Drug release (indomethacin), disintegration, tensile strength, and morphology (SEM) were evaluated.

Main Results:

• Excipient mechanical properties influenced tablet properties mainly at low polymer concentrations or high polymer concentrations with low-temperature curing.
• At high polymer levels (40%) and elevated temperatures (70°C), excipient type (lactose vs. mannitol) did not affect tablet properties.
• Compression stresses did not appear to be a significant driving force for matrix formation under the tested conditions.

Conclusions:

• Tablet compression stresses are not a primary driver for polymer matrix formation, especially at higher polymer concentrations and temperatures.
• Formulation and processing parameters, including polymer content and thermal treatment, significantly impact tablet properties.
• Understanding these relationships is key for designing controlled-release dosage forms.