Myristyl Alcohol
(mir is' til al' ka hol).
DEFINITION
Myristyl Alcohol contains NLT 90.0% of myristyl alcohol (C14H30O), the remainder consisting chiefly of related alcohols.
IDENTIFICATION
•  A. The retention time of the major peak of the Sample solution corresponds to that of the System suitability solution, as obtained in the Assay.
ASSAY
•  Procedure
System suitability solution:  9 mg/mL of USP Myristyl Alcohol RS and 1 mg/mL of USP Cetyl Alcohol RS in alcohol
Sample solution:  10 mg/mL of Myristyl Alcohol in dehydrated alcohol
Chromatographic system 
Mode:  GC
Detector:  Flame ionization
Column:  3-mm × 2-m, packed with 10% liquid phase G2 on support S1A
Temperature 
Column:  205
Detector:  250
Injector port:  275
Carrier gas:  Helium
Injection size:  2 µL
System suitability 
Sample:  System suitability solution
Suitability requirements 
Resolution:  NLT 4.0 between cetyl alcohol and myristyl alcohol
Relative standard deviation:  NMT 1.5%
Analysis 
Sample:  Sample solution
Calculate the percentage of myristyl alcohol (C14H30O) in the portion of Myristyl Alcohol taken:
Result = (rU/rT) × 100
rU== peak area of myristyl alcohol from the Sample solution
rT== sum of the peak areas except the solvent peak from the Sample solution
Acceptance criteria:  NLT 90.0%
SPECIFIC TESTS
•  Fats and Fixed Oils, Hydroxyl Value 401
Sample:  Place 2 g in a dry, glass-stoppered, 250-mL flask, and add 2 mL of pyridine, followed by 10 mL of toluene. To the mixture add 10.0 mL of a solution of acetyl chloride, prepared by mixing 10 mL of acetyl chloride with 90 mL of toluene. Insert the stopper in the flask, and immerse in a water bath heated at 60 to 65 for 20 min. Add 25 mL of water, again insert the stopper in the flask, and shake vigorously for several minutes to decompose the excess acetyl chloride.
Titrimetric system 
Mode:  Residual titration
Titrant:  Acetyl chloride
Back titrant:  1 N sodium hydroxide VS
Blank:  Proceed as directed for the Sample, omitting Myristyl Alcohol.
Endpoint detection:  Colorimetric
Analysis:  Add 0.5 mL of phenolphthalein TS to the Sample and Blank. Titrate each to a permanent pink endpoint with 1 N sodium hydroxide VS, shaking the flask vigorously toward the end of the titration to maintain the contents in an emulsified condition.
Calculate the hydroxyl value:
Result = [(VU VB) × F]/W
VU== volume of 1 N sodium hydroxide consumed by the Sample (mL)
VB== volume of 1 N sodium hydroxide consumed by the Blank (mL)
F== equivalent weight of potassium hydroxide, 56.1 mg/mEq
W== weight of the Sample (g)
Acceptance criteria:  250–267
ADDITIONAL REQUIREMENTS
•  Packaging and Storage: Preserve in well-closed containers.
•  USP Reference Standards 11
USP Cetyl Alcohol RS Click to View Structure
USP Myristyl Alcohol RS Click to View Structure
Auxiliary Information— Please check for your question in the FAQs before contacting USP.
Topic/Question Contact Expert Committee
Monograph Robert H. Lafaver, M.S.
Scientific Liaison
1-301-816-8335
(EXC2010) Monographs - Excipients
Reference Standards RS Technical Services
1-301-816-8129
rstech@usp.org
USP35–NF30 Page 1873
Pharmacopeial Forum: Volume No. 28(2) Page 424