USP Octinoxate RS [octyl methoxycinnamate] —Do not dry. Keep container tightly closed. Store in a cool place. Protect from light.

USP Octisalate RS [octyl salicylate] —Do not dry. Keep container tightly closed.USP29

USP Octocrylene RS— Do not dry. After opening ampul, store in a tightly closed container.

USP Octoxynol 9 RS— Do not dry before using. Keep container tightly closed.

USP Octyldodecanol RS— Do not dry before using. Keep container tightly closed.

USP Ofloxacin RS— Do not dry before using. Keep container tightly closed and protected from light.

USP Ofloxacin Related Compound A RS [9-fluoro-3-methyl-7-oxo-10-(piperazin-1-yl)-2,3-dihydro-7H-pyrido[1,2,3-de]-1,4-benzoxazine-6-carboxylic acid].

USP Oleoyl Polyoxylglycerides RS— Do not dry. After opening the ampul, store the material in a tightly closed container.

USP Omeprazole RS— Do not dry before using. Keep container tightly closed, and store in a cold place, protected from moisture.

USP Ondansetron Hydrochloride RS— This is the dihydrate form. Do not dry. For quantitative applications, determine the water content titrimetrically. Keep container tightly closed. Protect from light.

USP Ondansetron Related Compound A RS [3[(dimethylamino)methyl]-1,2,3,9-tetrahydro-9-methyl-4H-carbazol-4-one] —Do not dry. Keep container tightly closed. Protect from light.

USP Ondansetron Related Compound B RS [6,6¢-methylene bis-[(1,2,3,9-tetrahydro-9-methyl-3-[(2-methyl-1H-imidazol-1-yl)-methyl]-4H-carbazol-4-one] .

USP Ondansetron Related Compound C RS [1,2,3,9-tetrahydro-9-methyl-4H-carbazol-4-one] —Do not dry. Keep container tightly closed. Store in a refrigerator.

USP Ondansetron Related Compound D RS [1,2,3,9-tetrahydro-9-methyl-3-methylene-4H-carbazol-4-one] —Do not dry. Keep container tightly closed. Protect from light. Store in a refrigerator.

USP Ondansetron Resolution Mixture RS— Ondansetron hydrochloride having approximately 0.4% w/w of both ondansetron related compound A and 6,6¢-methylene bis-[(1,2,3,9-tetrahydro-9-methyl-3-[(2-methyl-1H-imidazol-1-yl)-methyl]-4H-carbazol-4-one)]—Do not dry. Keep container tightly closed. Protect from light. Store in a refrigerator.

USP Orphenadrine Citrate RS— Dry portion at 105 for 3 hours before using. Keep container tightly closed. Protect from light.

USP Oxacillin Sodium RS— Do not dry before using. Keep container tightly closed. Store at a controlled room temperature.

USP Oxandrolone RS— Dry portion at 105 for 3 hours before using. Keep container tightly closed. Protect from light.

USP Oxaprozin RS— Dry portion over silica gel at room temperature for 24 hours before using. Keep container tightly closed. Protect from light.

USP Oxazepam RS— Dry portion at a pressure below 5 mm of mercury at 105 for 3 hours before using. Keep container tightly closed.

USP Oxfendazole RS— Do not dry. Keep container tightly closed. Protect from light.

USP Oxprenolol Hydrochloride RS— Do not dry. Keep container tightly closed. Protect from light.

USP Oxtriphylline RS— Dry portion at 80 for 4 hours before using. Keep container tightly closed. Protect from light.

USP Oxybenzone RS— Dry portion in vacuum at 40 for 2 hours before using. Keep container tightly closed. Protect from light.

USP Oxybutynin Chloride RS— Dry portion in vacuum at 60 for 24 hours before using. Keep container tightly closed.

USP Oxybutynin Related Compound A RS [phenylcyclohexylglycolic acid] (C14H18O3 234.30) —Dry portion at 105 for 2 hours. Keep container tightly closed. Store in a dry place.

USP Oxybutynin Related Compound B RS [methyl ester of phenylcyclohexylglycolic acid, or CHMME (cyclohexyl mandelic acid methyl ester)]—Do not dry. Keep container tightly closed. Protect from light.

USP Oxybutynin Related Compound C RS [methylethyl analog of oxybutynin chloride, or (4-(ethylmethylamino) but-2-ynyl (±) 2-cyclohexyl-2-hydroxy-2-phenylacetate hydrochloride)]— Do not dry. Store in a tightly closed container blanketed under inert gas. Protect from light. This material is hygroscopic.

USP Oxycodone RS— Dry portion at 105 for 4 hours before using. Keep container tightly closed.

USP Oxygen–Helium RS.

USP Oxymetazoline Hydrochloride RS— Do not dry. Keep container tightly closed.

USP Oxymetholone RS— Dry portion in vacuum over phosphorus pentoxide for 4 hours before using. Keep container tightly closed.

USP Oxymorphone RS— Do not dry before using. Keep container tightly closed and protected from light.

USP Oxyquinoline Sulfate RS— Do not dry. Keep container tightly closed.

USP Oxytetracycline RS— Do not dry. Keep container tightly closed. Protect from light. Store in a cold place.

USP Oxytocin RS— Store at or below 0. Reconstitute the entire content of one vial in water, quantitatively transfer with water to a 5-mL volumetric flask, dilute with water to volume, and mix. For the System suitability test spike a portion of the final solution with chlorobutanol.