MeltingPointQualityChecker

Melting Point Quality Checker — Control of Melting Point

ℹ️  Utility checks compliance of melting point with pharmacopoeial requirements (Ph. Eur. 2.2.14 / USP <741>):
   • Onset Temperature: must be ≥ specified minimum.
   • Clear Point Temperature: must be ≤ specified maximum.
   • Melting Range: narrow range indicates high substance purity.

⚠️  CRITICAL: Depression of onset temperature and widening of range indicate presence of impurities!
   This is a classic test for identity and purity of crystalline substances.

Usage:
 MeltingPointQualityChecker.exe                            → demo mode (console output)
 MeltingPointQualityChecker.exe input.csv output.json      → evaluate your data

Input format:
BatchNumber,OnsetTemperature,ClearPointTemperature,MinOnsetLimit,MaxClearPointLimit

Example:
 MP-API-2026-001,153.5,154.8,153.0,155.0

— WHY IS THIS NEEDED?
Melting point is a fundamental physical constant of solid drug substances.
• Used for API identification and purity control.
• Impurities lower melting point and widen melting range (colligative properties).
• Ph. Eur. 2.2.14 describes several methods (capillary, hot stage, automatic instruments).
• Automation eliminates interpretation errors.

⚠️  CRITICAL:
• Heating rate must be strictly controlled (usually 1-2 °C/min near mp).
• Sample must be thoroughly dried and ground.
• For polymorphic substances, melting point may depend on crystal form.
• Decomposition at melting point may complicate clear point determination.

Key features:
• Verification of melting range boundaries.
• Assessment of range width as purity indicator.
• Support for automatic instrument data (Buchi, Mettler Toledo).

Critical parameters:
• Onset Temperature: >= Min Limit
• Clear Point Temperature: <= Max Limit
• Melting Range: Typically <= 2.0 °C

💡 Usage tips:
1. Calibrate instrument using certified standards (e.g., diphenylamine, resorcinol).
2. Use same amount of sample for each measurement.
3. Account for atmospheric pressure influence (for high temperatures).
4. If in doubt, confirm purity by chromatographic methods.
5. For polymorphs, use DSC for more detailed phase transition analysis.

⚠️ Note: Automatic instruments determine onset and end of melting optically or thermally. Visual method is subjective, so automation is preferred for GMP.