SUBUTEX (buprenorphine) sublingual tablet is an uncoated oval white flat bevelled edged tablet, debossed with an alphanumeric word identifying the product and strength on one side. It contains buprenorphine HCl, a partial agonist at the mu-opioid receptor, and is available in two dosage strengths, 2 mg buprenorphine and 8 mg buprenorphine (as the free base, equivalent to 2.16 mg buprenorphine hydrochloride USP and 8.64 mg buprenorphine hydrochloride USP). Each tablet also contains lactose, mannitol, cornstarch, povidone K30, citric acid, sodium citrate and magnesium stearate.

Chemically, buprenorphine HCl is (2S)-2-[17-Cyclopropylmethyl-4,5α-epoxy-3-hydroxy-6-methoxy6α,14-ethano-14α-morphinan-7α-yl]-3,3-dimethylbutan-2-ol hydrochloride. It has the following chemical structure:

Buprenorphine HCl has the molecular formula C₂₉ H₄₁ NO₄ • HCl and the molecular weight is 504.10. It is a white or off-white crystalline powder, sparingly soluble in water, freely soluble in methanol, soluble in alcohol and practically insoluble in cyclohexane.