Abstract
Background & Objective: Accelerated stability study (40°C/75% RH, 6 months) as well as long term stability studies (30°C/65% RH, 36 months) are conducted on three batches (I-III) of two commercially available CNS active herbal products (A and B) containing Convolvulus pluricaulis with Centella asiatica or Bacopa monnieri.
Methods: Stability samples were withdrawn at periodic intervals, and evaluated for physical stability (color, clarity, viscosity and pH), chemical stability (total phenolic (TPC), scopoletin, asiatic acid and bacoside A content), and biological activities (free radical scavenging, anti-acetylcholinesterase, and antianxiety). All stability samples retained the physical characteristics compared to corresponding control samples. Control samples exhibited significant batch-to-batch variation in TPC (46.8-65.9 mgGAE/L), scopoletin (165.78-206.15 ng/mL in A and 2.61-28.78 ng/mL in B), asiatic acid (30.14-44.92 μg/mL in B), free radical scavenging activity (IC50 0.5-1.25% v/v), AChE inhibitory activity (IC50 75.0-96.3% v/v), and antianxiety activity.
Results: The chemical indicators and biological activities were significantly decreased in both accelerated and long term stability samples compared to corresponding control samples. A correlation between scopoletin and biological activities was established in products A whereas asiatic acid/C. asiatica defies the logical correlation in product B.
Conclusion: The products exhibited significant batch-to-batch variation, and did not remain stable for the recommended shelf life period of three years, which suggested that these are suspected to lose therapeutic efficacy during their shelf life.
Keywords: Stability, Centella asiatica, Bacopa monnieri, Convolvulus pluricaulis, Brahmi, Shankhpushpi, Shelf life.
Graphical Abstract
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