Propylene Glycol Alginate
(proe' pi leen glye' kol al' ji nate).
DEFINITION
Propylene Glycol Alginate is a propylene glycol ester of alginic acid. Each gram yields NLT 0.16 and NMT 0.20 g of carbon dioxide, calculated on the dried basis.
IDENTIFICATION
• A.
Sample solution:
Place 20 mL of the saponified solution obtained in the determination of Esterified Carboxyl Groups in a 250-mL conical flask. Add 50 mL of a solution of periodic acid (1 in 50), swirl, and allow to stand for 30 min. Add 2 g of potassium iodide, titrate with sodium thiosulfate TS to a faint yellow color, dilute the mixture with water to 200 mL, and mix to obtain the Sample solution for Identification test A and Identification test B.
Modified Schiff's reagent:
Dissolve 200 mg of rosaniline hydrochloride (C20H20ClN3) in 120 mL of hot water. Cool, add 2 g of sodium bisulfite (NaHSO3), followed by 2 mL of hydrochloric acid, and dilute with water to 200 mL. [Note—Store this solution in a brown bottle at 15
or lower. ]
or lower. ]
Analysis:
To 10 mL of the Sample solution add 5 mL of hydrochloric acid and 10 mL of Modified Schiff's reagent.
Acceptance criteria:
A blue to blue-violet color, due to formaldehyde, develops in about 20 min.
• B.
Analysis:
To 10 mL of the Sample solution prepared in Identification test A add 1 mL of a saturated solution of piperazine and 0.5 mL of sodium nitroferricyanide TS.
Acceptance criteria:
A green color, due to acetaldehyde, develops.
ASSAY
• Content of Alginate
Analysis:
Proceed as directed for Procedure in Alginates Assay 
311
, without preliminary drying of the Propylene Glycol Alginate.
311, without preliminary drying of the Propylene Glycol Alginate.
Acceptance criteria:
0.16–0.20 g of carbon dioxide/g of Propylene Glycol Alginate, calculated on the dried basis
OTHER COMPONENTS
• Free Carboxyl Groups
Sample:
1 g
Titrimetric system
Mode:
Direct titration
Titrant:
0.1 N sodium hydroxide VS
Endpoint detection:
Potentiometric
Analysis:
Transfer the Sample to a 600-mL beaker. Dissolve in 200 mL of water, stirring by mechanical means for NLT 30 min. Titrate with 0.1 N sodium hydroxide VS to a pH of 7.0.
Calculate the weight, in g, of free carboxyl groups in the Sample taken:
Result = [(V × Mr × N)/W] × F
| V | = | = Titrant volume consumed (mL) |
| Mr | = | = mEq of CO2, 44 mg/mEq |
| N | = | = actual normality of the Titrant (mEq/mL) |
| W | = | = Sample weight (g) |
| F | = | = conversion factor, 10 3 g/mg |
Acceptance criteria:
The weight of free carboxyl groups found, calculated on the dried basis, is NMT 35% of the weight of carbon dioxide yielded by an equal weight of specimen in the Assay.
• Esterified Carboxyl Groups
Sample solution:
The solution obtained in the test for Free Carboxyl Groups
Analysis:
Transfer the Sample solution with the aid of water to a 1000-mL conical flask. Add phenolphthalein TS and 50.0 mL of 0.1 N sodium hydroxide VS, insert a stopper in the flask, mix, and allow to stand for 30 min at ambient temperature. Titrate the excess sodium hydroxide with 0.1 N hydrochloric acid VS to a faint pink endpoint. Transfer the solution with the aid of water to a 600-mL beaker, and complete the titration to a pH of 7.0, determining the endpoint potentiometrically.
Calculate the weight, in g, of esterified carboxyl groups in the weight, W, in g, of the specimen taken:
Result = [(V × Mr × N)/W] × F
| V | = | = volume of 0.1 N sodium hydroxide consumed (mL) |
| Mr | = | = mEq of CO2, 44 mg/mEq |
| N | = | = actual normality of 0.1 N sodium hydroxide (mEq/mL) |
| W | = | = specimen weight (g) |
| F | = | = conversion factor, 103 g/mg |
Acceptance criteria:
The weight of esterified carboxyl groups found, calculated on the dried basis, is 40%–85% of the weight of carbon dioxide yielded by an equal weight of specimen in the Assay.
IMPURITIES
• Arsenic, Method II 211:
3 ppm
211:
3 ppm
• Heavy Metals, Method II 231:
NMT 40 ppm, using a platinum crucible for the ignition, and nitric acid being used in place of sulfuric acid to wet the sample specimen
231:
NMT 40 ppm, using a platinum crucible for the ignition, and nitric acid being used in place of sulfuric acid to wet the sample specimen
• Lead 251
251
Standard solution:
5 mL of Diluted Standard Lead Solution
Test preparation:
Add 1.0 g to 20 mL of nitric acid in a 250-mL conical flask, mix, and heat carefully until the specimen is dissolved. Continue the heating until the volume is reduced to 7 mL. Cool rapidly to room temperature, transfer to a 100-mL volumetric flask, dilute with water to volume, and mix. Use a 50-mL portion.
Analysis:
Proceed as directed in the chapter, using 15 mL of ammonium citrate solution, 3 mL of potassium cyanide solution, and 0.5 mL of hydroxylamine hydrochloride solution for the test. After the first dithizone extractions, wash the combined chloroform layers with 5 mL of water, discarding the water layer and continuing in the usual manner by extracting with 20 mL of 0.2 N nitric acid.
Acceptance criteria:
A 50.0-mL portion of this solution contains NMT 5 µg of lead (corresponding to NMT 10 ppm of Pb).
SPECIFIC TESTS
• Microbial Enumeration Tests 61 and Tests for Specified Microorganisms 62:
The total bacterial count does not exceed 200 cfu/g, and the tests for Salmonella species and Escherichia coli are negative.
61 and Tests for Specified Microorganisms 62:
The total bacterial count does not exceed 200 cfu/g, and the tests for Salmonella species and Escherichia coli are negative.
• Loss on Drying 731:
Dry a sample at 105 for 4 h: it loses NMT 20.0% of its weight.
731:
Dry a sample at 105 for 4 h: it loses NMT 20.0% of its weight.
• Ash
Sample:
3 g
Analysis:
Weigh the Sample in a tared crucible, and incinerate at 650 ± 25 until free from carbon. Cool in a desiccator, weigh, and determine the weight of the ash.
until free from carbon. Cool in a desiccator, weigh, and determine the weight of the ash.
Acceptance criteria:
NMT 10.0% on the dried basis
ADDITIONAL REQUIREMENTS
• Packaging and Storage:
Preserve in well-closed containers.
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 |
| 61 |
Radhakrishna S Tirumalai, Ph.D.
Principal Scientific Liaison 1-301-816-8339 |
(GCM2010) General Chapters - Microbiology |
| 62 |
Radhakrishna S Tirumalai, Ph.D.
Principal Scientific Liaison 1-301-816-8339 |
(GCM2010) General Chapters - Microbiology |
USP35–NF30 Page 1932