Dear Dr Rajesh, as a general rule for any tox study you have to administer/apply the drug through intended clinical route at various dose levels (far above the intended therapeutic dose). So you may go ahead to apply subgingivally in rat for acute or repeated dose tox study. Additionally, you must understand that drug is ultimately reaching in systemic circulation even after subgingival application. Therefore, additional tox studies may be conducted via repeated oral administration.

Goog Luck !

Thank you Mr. Gulam Husain. I am doing the study following OECD guidelines now.