From the FLCCC:
Yes, the ivermectin in both formulations is pharmacologically equivalent, however there is a difference in the amount of impurities contained within each. The human formulations have highly regulated and thus very low levels of impurities. We cannot recommend veterinary formulations given the lack of safety data around their use, however we are also not aware of any associated toxicity.
https://covid19criticalcare.com/i-mask-prophylaxis-treatment-protocol/faq-on-ivermectin/
From the FDA:
Pharmaceutical Equivalents. Pharmaceutical equivalents are drug products in identical dosage forms and route(s) of administration that contain identical amounts of the identical active drug ingredient, i.e., the same salt or ester of the same therapeutic moiety, or, in the case of modified-release dosage forms that require a reservoir or overage or such forms as prefilled syringes where the residual volume may vary, that deliver identical amounts of the active drug ingredient over the identical dosing period; do not necessarily contain the same inactive ingredients; and meet the identical compendial or other applicable standard of identity, strength, quality, and purity, including potency and, where applicable, content uniformity, disintegration times, and/or dissolution rates.2 They may differ in characteristics such as shape, scoring configuration, release mechanisms, packaging, excipients (including colors, flavors, preservatives), expiration date/time, and, within certain limits, labeling.
https://www.fda.gov/drugs/development-approval-process-drugs/orange-book-preface#:~:text=Pharmaceutical%20equivalents%20are%20drug%20products,require%20a%20reservoir%20or%20overage