Panthenol
(pan' the nol).
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C9H19NO4 205.25
Butanamide, 2,4-dihydroxy-N-(3-hydroxypropyl)-3,3-dimethyl-, (±)-;    
(±)-2,4-Dihydroxy-N-(3-hydroxypropyl)-3,3-dimethylbutyramide;    
(±)-Pantothenyl alcohol     [16485-10-2].
DEFINITION
Panthenol is a racemic mixture of the dextrorotatory and levorotatory isomers of panthenol. It contains NLT 99.0% and NMT 102.0% of racemic panthenol (C9H19NO4), calculated on the dried basis.
IDENTIFICATION
•  B.
Sample solution:  100 mg/mL of Panthenol
Analysis:  To 1 mL of the Sample solution add 5 mL of 1 N sodium hydroxide and 1 drop of cupric sulfate TS, and shake vigorously.
Acceptance criteria:  A deep blue color develops.
•  C.
Sample solution:  10 mg/mL of Panthenol
Analysis:  To 1 mL of the Sample solution add 1 mL of 1 N hydrochloric acid, and heat on a steam bath for 30 min. Cool, add 100 mg of hydroxylamine hydrochloride, and add 5 mL of 1 N sodium hydroxide. Allow to stand for 5 min, then adjust with 1 N hydrochloric acid to a pH of 2.5–3.0, and add 1 drop of ferric chloride TS.
Acceptance criteria:  A purplish red color develops.
ASSAY
•  Procedure
0.1 M potassium biphthalate:  Transfer 20.42 g of potassium biphthalate into a 1000-mL volumetric flask, and add sufficient glacial acetic acid to dissolve. If necessary, warm the mixture on a steam bath to achieve complete solution, observing precautions against absorption of moisture. Cool to room temperature, and dilute with glacial acetic acid to volume.
Sample:  400 mg of Panthenol
Blank:  Proceed as directed in the Analysis, omitting the Sample.
Titrimetric system 
Mode:  Residual titration
Titrant:  0.1 N perchloric acid VS
Back-titrant:  0.1 M potassium biphthalate
Endpoint detection:  Visual
Analysis:  Transfer the Sample to a 300-mL flask fitted to a reflux condenser by means of a standard-taper glass joint, add 50.0 mL of Titrant, and reflux for 5 h. Cool, observing precautions to prevent atmospheric moisture from entering the condenser, and rinse the condenser with glacial acetic acid, collecting the rinsings in the flask. To the flask add 5 drops of crystal violet TS, and titrate with the Back-titrant to a blue-green endpoint. Perform the Blank determination.
Calculate the percentage of panthenol (C9H19NO4) in the Sample taken:
Result = {[(VB VS) × M × F]/W} × 100
VB== Back-titrant volume consumed by the Blank (mL)
VS== Back-titrant volume consumed by the Sample (mL)
M == actual molarity of the Back-titrant (mM/mL)
F== equivalency factor, 205.3 mg/M
W== Sample weight (mg)
Acceptance criteria:  99.0%–102.0% on the dried basis
IMPURITIES
•  Residue on Ignition 281: NMT 0.1%
•  Limit of Aminopropanol
Sample:  10 g of Panthenol
Blank:  25 mL of water
Titrimetric system 
Mode:  Direct titration
Titrant:  0.01 N sulfuric acid VS
Endpoint detection:  Visual
Analysis:  Dissolve the Sample in 25 mL of water, and add bromothymol blue TS. Titrate with the Titrant to a yellow endpoint. Perform the Blank determination.
Calculate the percentage of aminopropanol in the Sample taken:
Result = {[(VS VB) × N × F]/W} × 100
VS== Titrant volume consumed by the Sample (mL)
VB== Titrant volume consumed by the Blank (mL)
N== actual normality of the Titrant (mEq/mL)
F== equivalency factor, 75.11 mg/mEq
W== Sample weight (mg)
Acceptance criteria:  NMT 0.10%
SPECIFIC TESTS
•  Melting Range, Class I 741: 64.5–68.5
•  Optical Rotation, Specific Rotation 781S
Sample solution:  50 mg/mL in water
Acceptance criteria:  0.05 to +0.05
•  Loss on Drying 731: Dry a sample in a vacuum over phosphorus pentoxide at 56 for 4 h: it loses NMT 0.5% of its weight.
ADDITIONAL REQUIREMENTS
•  Packaging and Storage: Preserve in tight containers.
•  USP Reference Standards 11
USP Racemic Panthenol RS Click to View Structure
Auxiliary Information— Please check for your question in the FAQs before contacting USP.
Topic/Question Contact Expert Committee
Monograph Huy T. Dinh, M.S.
Scientific Liaison
1-301-816-8594
(DS2010) Monographs - Dietary Supplements
Reference Standards RS Technical Services
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rstech@usp.org
USP35–NF30 Page 4208