When sourcing Lidocaine in bulk, the purity level should ideally be ≥99% to ensure efficacy and safety. Buyers must distinguish between Lidocaine Base (CAS 137-58-6), which is oil-soluble and often used in topical ointments, and Lidocaine Hydrochloride (Lidocaine HCl, CAS 73-78-9), which is water-soluble and typically used for injections or sprays. Ensure the product meets USP (United States Pharmacopeia), BP (British Pharmacopoeia), or EP (European Pharmacopoeia) standards, and request a Certificate of Analysis (COA) for every batch to verify heavy metal limits and impurity profiles.