Impact breakage of pharmaceutical tablets

Area of Science:

• Pharmaceutical Sciences
• Materials Science
• Mechanical Engineering

Background:

• Tablets are the most common solid dosage form, but their robustness is crucial for preventing breakage during production, transport, and use.
• Existing tablet strength tests, such as diametric compression and friability, do not correlate well with fundamental mechanical properties responsible for breakage.
• Understanding and measuring tablet mechanical properties like hardness, elastic modulus, and fracture toughness are essential for optimizing tablet quality.

Purpose of the Study:

• To propose and evaluate a novel single tablet impact testing method for assessing tablet strength and breakage propensity.
• To compare the proposed impact testing method with traditional diametric compression and microindentation techniques.
• To establish a correlation between impact testing results and fundamental mechanical properties of pharmaceutical tablets.

Main Methods:

• Developed a single tablet impact testing apparatus based on prior work analyzing particle damage.
• Conducted microindentation tests separately to determine fracture toughness and Young's modulus.
• Compared results from impact testing, microindentation, diametric compression, and friability tests.

Main Results:

• Microindentation tests led to tablet failure, yielding unreliable fracture toughness measurements and poor correlation with Young's modulus.
• Single tablet impact testing provided a more reliable measure of tablet breakage propensity, correlating better with mechanical properties.
• Impact testing results showed discrepancies with indentation methods, likely due to variations in mechanical properties and strain rates across the tablet surface.

Conclusions:

• Single tablet impact testing is a more suitable method for evaluating tablet attrition and predicting breakage during processing compared to compression and friability tests.
• The proposed impact method directly represents failure modes experienced during processing under defined conditions.
• Traditional tests do not accurately reflect the mechanical properties governing tablet breakage, highlighting the need for advanced testing methodologies.