(a) The controlled substances listed in this section are included in Schedule V.
(b) Any compound, mixture or preparation containing limited quantities of any of the following narcotic drugs, which also contains 1 or more nonnarcotic active medicinal ingredients in sufficient proportion to confer upon the compound, mixture or preparation valuable medicinal qualities other than those possessed by the narcotic drug alone:
(1) Not more than 200 milligrams of codeine or any of its salts per 100 milliliters or per 100 grams;
(2) Not more than 100 milligrams of dihydrocodeine or any of its salts per 100 milliliters or per 100 grams;
(3) Not more than 100 milligrams of ethylmorphine or any of its salts per 100 milliliters or per 100 grams;
(4) Not more than 2.5 milligrams of diphenoxylate and not less than 25 micrograms of atropine sulfate per dosage unit;
(5) Not more than 100 milligrams of opium per 100 milliliters or per 100 grams; and
(6) Not more than 0.5 milligram and no less than 24 micrograms of atropine sulfate per dosage unit.
(c) Buprenorphine and its salts.