Phentermine hydrochloride USP has the chemical name of α α Dimethylphenethylamine hydrochloride. The structural formula is as follows: Phentermine hydrochloride is a white, odorless, hygroscopic, crystalline powder which is soluble in water and lower alcohols, slightly soluble in chloroform and insoluble in ether. ADIPEX-P® (phentermine hydrochloride) , an anorectic agent for oral administration, is available as a capsule or tablet containing 37.5 mg of phentermine hydrochloride (equivalent to 30 mg of phentermine base). ADIPEX-P® (phentermine hydrochloride) Capsules contain the inactive ingredients Corn Starch, Gelatin, Lactose Monohydrate, Magnesium Stearate, Titanium Dioxide, Black Iron Oxide, FD&C Blue #1, FD&C Red #40 and D&C Red #33. ADIPEX-P® (phentermine hydrochloride) Tablets contain the inactive ingredients Corn Starch, Lactose (Anhydrous), Magnesium Stearate, Microcrystalline Cellulose, Pregelatinized Starch, Sucrose, and FD&C Blue #1.