A drop penetration method to measure powder blend wettability

Area of Science:

• Pharmaceutical Sciences
• Materials Science
• Physical Chemistry

Background:

• Water wettability of pharmaceutical blends is crucial for final product quality.
• Magnesium Stearate (MgSt) is a common lubricant affecting blend properties.
• Mechanical stress can alter powder surface characteristics.

Purpose of the Study:

• To investigate the effect of mechanical shear strain on the wettability of a pharmaceutical blend.
• To evaluate a novel drop penetration method for assessing powder blend quality.

Main Methods:

• Studied a blend of Acetaminophen, Lactose, and Magnesium Stearate (MgSt).
• Measured sessile drop penetration dynamics of water and silicon oil on compressed powder beds.
• Quantified wettability via effective cosine of the contact angle.
• Exposed blends to increasing shear strain levels.

Main Results:

• Increased shear strain significantly decreased water wettability (reduced cosine of contact angle).
• Hydrophobic film formation on powder particles correlated with shear strain.
• Dissolution times increased with higher levels of shear strain.

Conclusions:

• Mechanical shear strain negatively impacts pharmaceutical blend wettability.
• The drop penetration method effectively assesses MgSt lubrication and blend quality.
• This method can serve as a quality control tool before tableting.