Limit for Butylated hydroxytoluene

[nsreenivas]

Can anybody please suggest - what is the limit for Butylated hydroxytoluene in Pharmaceutical drug substances.

regards,
n sreenivas

[bkirschil]

BHT is generally used as an antioxidant in pharmaceuticals. In solid formulations, it's concentration is generally about 0.01%, for IV injections, 0.0009 - 0.02%, for IM injections, 0.03%, inhalations, 0.01%, topicals, 0.0075 - 0.1%. This info comes from the Handbook of Pharmaceutical Excipients. What is your dosage form?

[nsreenivas]

Ours is not a dosage form. We are looking for BHT limit in Active Pharmaceutical Ingredient (API).

[bkirschil]

The amount of BHT in API depends on its usage in the substance. I don't know your answer, but I would think that it would also depend on its toxicity and total daily intake of your API in final dosage unit. If BHT is an impurity of your synthesis, its limit would probably be NMT 0.1%. If its placed in as antioxidant (don't know why unless API is liquid or solution) you may want to check with FDA's official excipient listing and common amounts (most are final dosage units). Aso, consideration must be given to other factors like API reactivity with BHT under various conditions. You can use my answers from last message and ultimate dosage form and strength of drug product and extrapolate back to amount permissable in API (if all eminating from API rather than added during processing).


bkirsch