Stability Studies of Herbal Extracts and Formulations

Stability studies establish the shelf-life of a herbal extract or finished formulation by monitoring its physical, chemical, and microbiological quality over time under defined storage conditions, following the ICH Q1A(R2) framework adapted for the Indian climatic zone (Zone IVb, characterised by hot and humid conditions). Accelerated stability testing is conducted at 40°C and 75% relative humidity over a six-month period to rapidly predict likely degradation pathways, while long-term (real-time) stability testing is conducted at 30°C and 65% relative humidity over the full proposed shelf-life, typically eighteen to twenty-four months or longer. Marker compound content, quantified by the validated HPLC method described above, must remain at or above ninety percent of the initial labelled content throughout the claimed shelf-life, while the HPTLC fingerprint profile is compared at each time point against the initial (time-zero) profile to confirm the absence of new degradation peaks or loss of existing characteristic peaks. Physical appearance, colour, and odour are documented at each time point, with significant darkening or off-odour development flagged as an early indicator of chemical degradation; moisture content is monitored throughout, since rising moisture content is itself both a direct quality concern and a risk factor for accelerated microbial growth; and microbial limits are re-tested at each stability time point to confirm that the product remains within acceptable limits throughout its claimed shelf-life. Where the finished product is a solid oral dosage form such as a tablet or capsule, dissolution profile comparison across the stability study provides a further critical performance-related stability endpoint.