The notes will pay interest at 5.75% and convert at a price of US$8.02 per share.
Money raised will fund both testing of trabodenoson as a monotherapy and as a fixed-dose combination with another drug, latanoprost, for the reduction of intraocular pressure.
Cowen and Company and Piper Jaffray will run the book jointly with an option to buy an additional US$7.5mln of notes if demand is sufficient.
Interest will be payable twice a year and the notes be convertible at the option of holders until the 2021 maturity date.
Inotek specialises in therapies for glaucoma and other eye diseases.
--updates for coupon and conversion price --