Case Study: Pharmaceutical DSC Polymorph Screening

DSF-AI detected all 5 thermal transitions including a glass transition and decomposition onset missed by standard peak-picking analysis.

The Data

Heat flow vs. temperature for a pharmaceutical compound, measured by differential scanning calorimetry (DSC) from 25°C to 300°C. 2,000 data points. The compound has a known glass transition, two polymorphic conversions, a melt, and a decomposition onset.

Results

Transition	Expected	DSF-AI Detected	Regime
Glass transition	~55°C	62°C	VOLATILE (61-63°C)
Polymorph I conversion	~86°C	86°C	VOLATILE (81-106°C)
Polymorph II conversion	~143°C	143°C	VOLATILE (139-148°C)
Melt	~211°C	211°C	VOLATILE (206-232°C)
Decomposition onset	~265°C	263°C	VOLATILE (263-300°C)

5 of 5 transitions detected. Standard manual peak-picking typically identifies only the two polymorphic peaks and the melt (3 of 5). The glass transition is a subtle step change, not a peak. The decomposition onset is a gradual exotherm, not a sharp feature.

Stability Map

DSF-AI classified the entire temperature range into distinct stability regions, identifying where the material is thermally quiet, actively transitioning, or approaching a transition:

Region	Range	Interpretation
STABLE	25-61°C	Stable glassy state, no thermal activity
VOLATILE	61-63°C	Glass transition
STABLE	63-70°C	Post-glass relaxation
TRANSITIONAL	70-81°C	Approaching polymorphic conversion
VOLATILE	81-106°C	Polymorph I conversion (broad)
DEGENERATE	108-139°C	Stable polymorphic form
VOLATILE	139-148°C	Polymorph II conversion
STABLE	148-158°C	Stable post-conversion
TRANSITIONAL	160-206°C	Pre-melt softening
VOLATILE	206-232°C	Melt
DEGENERATE	232-263°C	Liquid state
VOLATILE	263-300°C	Decomposition onset

Why This Matters for Pharma

ICH Q6A requires identification of all polymorphic forms. Missing a glass transition means missing an amorphous form. Missing a decomposition onset means potentially overstating thermal stability. DSF-AI provides a fast, automated first pass that flags every transition in the DSC curve — not just the obvious peaks.

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