A study of the consistency in selected Ghanaian herbal formulation over a 7-year period

Introduction: The growing global reliance on herbal medicines illustrates the importance of consistent quality, safety, and efficacy. In Ghana, where over 70% of adults use herbal products, the absence of standardized physicochemical parameters such as Total Solid Residue (TSR) and Total Water Extractive (TWE) poses regulatory and therapeutic challenges. This study evaluates the consistency of TSR, TWE, and colour across 70 production batches of Ghanaian herbal formulations over seven years. Methods: Seventeen decoctions, nine powders, and three ointments produced at the Centre for Plant Medicine Research (CPMR) were analyzed in triplicate using WHO and British Pharmacopoeia protocols. Colour variability was assessed using the RAL Classic guide. Statistical significance was determined using ANOVA with False Discovery Rate (FDR) adjustment (p < 0.05). Results: Decoctions exhibited stable TSR values (mean 4.3 ± 0.6% w/v), with most batches clustering within 4–5%. Only one decoction (D/011) showed significant inter-year variability (p = 0.009). Powders displayed a wider TWE range (12.6–38.8% w/w), with six products showing significant year-to-year variation. Ointments maintained consistent TWE values (2–22% w/w) and uniform colour profiles. No correlation was observed between colour and TSR (r = 0.076, p = 0.42). Conclusion: The findings demonstrate that the herbal decoctions, powders and ointments produced at CPMR remained standardized within the proposed benchmark ranges over seven years. The study also proposes evidence-based benchmark ranges for TSR and TWE to support regulatory standardization, enhance batch reproducibility, and ensure therapeutic consistency in Ghana's herbal medicine industry.