Significant efforts are necessary to develop an active pharmaceutical ingredient (API). It is therefore risky to expose this API to poorly characterized excipients with potential presence of many impurities (peroxides, aldehydes, organic acids, metals, residual solvents, etc.).
In many cases excipient is the key enabler of drug product performance and we have seen in the recent past several FDA recalls due to variability of excipients.
Natural based products are by definition subject to a certain degree of variability but appropriate solutions can be proposed by excipients suppliers.