Ensuring the quality and consistency of tablets and their coatings is critical. Quality control involves both in-process and finished product tests.
In-Process Tests
These tests are conducted during manufacturing to monitor and control the process parameters.
A) Powder Flowability
Purpose: Ensure that the powder blends flow smoothly through the manufacturing equipment.
Methods:
Angle of Repose: Measures the slope formed by poured powder.
Flow Through an Orifice: Measures the rate at which powder flows through a standardized opening.
Hausner Ratio: Compares tapped and bulk densities.
B) Granule Size Distribution
Purpose: Ensure uniform granule size for consistent tablet compression.
Methods:
Sieving: Passing granules through a series of sieves.
Laser Diffraction: Analyzing particle size based on light scattering.
C) Moisture Content
Purpose: Prevent issues like stickiness, microbial growth, or degradation.
Methods:
Karl Fischer Titration: Quantitative determination of water content.
Loss on Drying (LOD): Heating the sample and measuring weight loss.
D) Tablet Hardness Testing
Purpose: Ensure mechanical strength for handling and packaging.
Methods:
Compression Testing: Using a hardness tester to apply force until the tablet breaks.
E) In-Process Uniformity
Purpose: Monitor uniform distribution of API and excipients.
Methods:
Sampling: Regularly taking samples from batches for testing.
Finished Product Tests
These tests are conducted on the final tablet product to ensure it meets all quality specifications.
A) Weight Variation
Purpose: Ensure each tablet contains a consistent amount of content.
Methods:
Individual Weighing: Weighing a sample of tablets individually.
Statistical Analysis: Comparing mean and standard deviation against specifications.
B) Content Uniformity
Purpose: Ensure each tablet contains the exact amount of API.
Methods:
Spectroscopy: Using UV-Vis or IR spectroscopy to quantify API.
High-Performance Liquid Chromatography (HPLC): Precise measurement of API concentration.
C) Dissolution Testing
Purpose: Ensure the tablet releases the API at the desired rate.
Methods:
USP Apparatus: Using standardized dissolution apparatus (e.g., paddle, basket).
Spectrophotometric Analysis: Measuring API concentration in the dissolution medium over time.
D) Disintegration Testing
Purpose: Assess the tablet's ability to break down in the GI tract.
Methods:
USP Disintegration Tester: Placing tablets in a controlled medium and observing disintegration time.
E) Hardness and Friability
Hardness: Re-measured to confirm tablet strength.
Friability: Assesses the tablet's resistance to mechanical stress.
Method: Using a friabilator to rotate tablets and measure weight loss.
F) Coating Integrity
Purpose: Ensure the coating is uniform and defect-free.
Methods:
Visual Inspection: Checking for visible defects.
Microscopy: Analyzing coating thickness and uniformity.
Solvent Extraction: Quantifying coating material.
G) Stability Testing
Purpose: Assess the tablet's shelf life under various environmental conditions.
Methods:
Accelerated Stability Testing: Storing tablets at elevated temperature and humidity.
Real-Time Stability Testing: Monitoring tablets over extended periods under normal conditions.
H) Taste and Odor Assessment
Purpose: Ensure palatability, especially for chewable or ODTs.
Methods:
Sensory Evaluation: Trained panels assess taste and smell.
I) Uniformity of Coating
Purpose: Verify consistent coating thickness and appearance across all tablets.
Methods:
Thickness Measurement: Using micrometers or non-destructive techniques like near-infrared (NIR) spectroscopy.
Colorimetric Analysis: Ensuring consistent color intensity and hue.