Polyvinyl Acetate Dispersion

This article is compiled based on the United States Pharmacopeia (USP) – 2025 Edition

Issued and maintained by the United States Pharmacopeial Convention (USP)

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1 DEFINITION

Dispersion of polyvinyl acetate in water. It contains 25.0% to 30.0% of polyvinyl acetate. It may contain povidone and sodium lauryl sulfate as stabilizers.

2 IDENTIFICATION

2.1 A. Film Formation

Place 1 drop of Dispersion on a glass plate and allow to dry. A clear and homogeneous film is formed.

2.2 B. Infrared Absorption

(See Spectroscopic Identification Tests 〈197〉, Infrared Spectroscopy.)

Analysis: Place 1 drop of the Dispersion on a glass plate, and cover the test substance with a water-resistant crystal disk (silver chloride or KRS-5).¹ Gently press on, and then remove the crystal disk. Dry the crystal disk in a drying chamber until a homogeneous film is formed.

Acceptance criteria: The IR absorption spectrum of the film so formed exhibits maxima corresponding to the same wavelengths as those of a similar preparation of USP Polyvinyl Acetate Dispersion RS treated in the same manner.

3 ASSAY

Change to read:

3.1 Procedure

Sample 1: 10 g of Dispersion

Solvent: 50 mL of a mixture of equal volumes of alcohol and petroleum ether with a 100°–120° boiling range, which is previously neutralized with 0.1 N potassium hydroxide or 0.1 N sodium hydroxide

Analysis 1: Dissolve Sample 1 in the Solvent. Add 0.5 mL of phenolphthalein TS, and titrate with 0.1 N potassium hydroxide or 0.1 N sodium hydroxide until the pink color persists for at least 15 s.

Calculate the acid value, I_A:

Result = (M_r1 × V × N)/W

M_r1 = molecular weight of potassium hydroxide, 56.11

V = volume of 0.1 N potassium hydroxide or 0.1 N sodium hydroxide consumed in the actual test (mL)

N = exact normality of the potassium hydroxide solution or sodium hydroxide solution

W = weight of Dispersion taken for the test (g)

Sample 2: 1.5 g of Dispersion

Analysis 2: Transfer Sample 2 to a 250-mL borosilicate glass flask fitted with a reflux condenser. Add 25.0 mL of 0.5 M alcoholic potassium hydroxide and a few glass beads. Attach the condenser and heat under reflux for 30 min. Add 1 mL of phenolphthalein TS, and titrate immediately (while still hot) with 0.5 N hydrochloric acid VS. Perform a blank determination under the same conditions (see Titrimetry 〈541〉).

Calculate the saponification value, I_s:

Result = [M_r1 × (V_B − V_T) × N]/W

M_r1 = molecular weight of potassium hydroxide, 56.11

V_B = volume of 0.5 N hydrochloric acid consumed in the blank test (mL)

V_T = volume of 0.5 N hydrochloric acid consumed in the actual test (mL)

N = exact normality of the hydrochloric acid

W = weight of Dispersion taken for the test (g)

Calculate the percentage content of polyvinyl acetate in the portion of Dispersion taken:

Result = F × {M_r2 × [(I_s − I_A)/M_r1]} × 100

F = factor converting mg to g, 10⁻³ g/mg

M_r2 = molecular weight of vinyl acetate, 86.09

I_s = saponification value

I_A = acid value

M_r1 = molecular weight of potassium hydroxide, 56.11

Acceptance criteria: The content of polyvinyl acetate is 25.0%–30.0%.

4 OTHER COMPONENTS

4.1 Stabilizers

4.1.1 Povidone

[Note-Perform this test only if the Dispersion contains povidone.]

Sample: 0.25 g

Analysis: Perform nitrogen determination by sulfuric acid digestion on the Sample as directed in Nitrogen Determination 〈461〉, Method II. Calculate the percentage content of povidone in the portion of Dispersion taken:

Result = N/Nᵥ

N = percentage content of nitrogen

Nᵥ = percentage content, expressed as a decimal number, of nitrogen in vinylpyrrolidone, 0.126

Acceptance criteria: The content of povidone is NMT 4.0%.

5 IMPURITIES

5.1 Residue on Ignition 〈281〉

Sample: 1.0 g of Dispersion

Analysis: Heat a silica crucible to redness for 30 min, allow to cool in a desiccator, and weigh. Evenly distribute the Sample in the crucible and weigh. Dry the crucible at 100°–105° for 1 h and ignite in a muffle furnace at 600 ± 25°, until the test substance is thoroughly charred. Continue the experiment as directed in Residue on Ignition 〈281〉 on the residue obtained, beginning with “Moisten the sample with a small amount (usually 1 mL) of sulfuric acid…”

Acceptance criteria: NMT 0.5%

5.2 Limit of Vinyl Acetate

Solution A: Acetonitrile, methanol, and water (5:5:90)

Solution B: Acetonitrile, methanol, and water (45:5:50)

Mobile phase: See Table 1.

Table 1

Standard solution: Transfer 50 mg of vinyl acetate to a 100-mL volumetric flask, dissolve in and dilute with methanol to volume, and mix well. Dilute 5.0 mL of the solution with Solution A to 100 mL. Dilute 10.0 mL of this solution with Solution A to 100 mL. The Standard solution contains about 2.5 µg/mL of vinyl acetate. [Note-This solution should be analyzed within 1 h when stored at room temperature.]

System suitability solution: Transfer 50 mg of vinyl acetate and 50 mg of 1-vinylpyrrolidin-2-one to a 50-mL volumetric flask, add 10 mL of methanol, sonicate or gently shake the flask to dissolve the materials. Dilute with Solution A to volume. Dilute 10 mL of this solution with Solution A to 100 mL. Dilute 5 mL of this solution with Solution A to 100 mL. The System suitability solution contains about 5 µg/mL each of vinyl acetate and 1-vinylpyrrolidin-2-one.

Sample solution: Transfer 250 mg of Dispersion to a 10-mL volumetric flask, add about 4 mL of methanol, and sonicate. After cooling to ambient temperature, dilute with water to volume, and mix. Centrifuge at 4000 × g for 10 min, and pass through a 0.2-µm membrane filter. [Note-This solution should be analyzed within 1 h when stored at room temperature.]

Chromatographic system

• (See Chromatography 〈621〉, System Suitability.)
• Mode: LC
• Detector: UV 205 nm
• Columns
• Precolumn: 4.0-mm x 3-cm; 5-µm packing L1 may be used if a matrix effect is observed. [NOTE-The matrix effect may result in poor reproducibility of the retention times and of the peak shapes.]
• Analytical: 4.0-mm × 25-cm; 5-µm packing L1
• Column temperature: 30°
• Flow rate: 1 mL/min
• Injection volume: 10 µL

System suitability

• Sample: System suitability solution
• [Note-The relative retention times for vinyl acetate and 1-vinylpyrrolidin-2-one are 1.0 and 1.2, respectively.]
• Suitability requirements
• Resolution: NLT 5.0 between vinyl acetate and 1-vinylpyrrolidin-2-one
• Relative standard deviation: NMT 5.0% determined from the 1-vinylpyrrolidin-2-one peak

Analysis

Samples: Standard solution and Sample solution

Acceptance criteria: The response of the vinyl acetate peak from the Sample solution is NMT that of the vinyl acetate peak from the Standard solution, corresponding to NMT 100 ppm of vinyl acetate.

5.3 Limit of Acetic Acid/Acetate

Solution A: 5 mM sulfuric acid

Solution B: Acetonitrile and 5 mM sulfuric acid (1:1)

Mobile phase: See Table 2.

Table 2

System suitability solution: Transfer 30 mg of glacial acetic acid and 30 mg of malonic acid to a 25-mL volumetric flask, dilute with methanol to volume, and mix well. Transfer 1 mL of the solution to a 25-mL flask, dilute with water to volume, and mix well. The solution contains 0.048 mg/mL each of acetic acid and malonic acid.

Standard solution: 0.1 mg/mL of acetic acid in water

Sample solution: Transfer 330 mg of Dispersion to a 50-mL volumetric flask, add about 5 mL of methanol, and dilute with water to volume, which leads to a precipitation of sample. Pass the dispersion through a 0.2-µm regenerated cellulose membrane filter.² Use the filtrate.

Chromatographic system

• (See Chromatography 〈621〉, System Suitability.)
• Mode: LC
• Detector: UV 205 nm
• Column: 4.6-mm × 25-cm; 5-µm packing L1
• Column temperature: 25°
• Flow rate: 1 mL/min
• Injection volume: 20 µL
• Run time: 30 min

System suitability

• Samples: System suitability solution and Standard solution
• [Note-The relative retention times for malonic acid and acetic acid are 0.9 and 1.0, respectively.]
• Suitability requirements
• Resolution: NLT 2.0 between malonic acid and acetic acid, System suitability solution
• Relative standard deviation: NMT 5.0% determined from the acetic acid peak, Standard solution

Analysis

Samples: Standard solution and Sample solution

Calculate the percentage of acetic acid in the portion of Dispersion taken:

Result = (rᵤ/rₛ) × (Cₛ/Cᵤ) × 100

rᵤ = peak response of acetic acid from the Sample solution

rₛ = peak response of acetic acid from the Standard solution

Cₛ = concentration of acetic acid in the Standard solution (mg/mL)

Cᵤ = concentration of Polyvinyl Acetate Dispersion in the Sample solution (mg/mL)

Acceptance criteria: NMT 1.5% of acetic acid

6 SPECIFIC TESTS

6.1 Microbial Enumeration Tests 〈61〉 and Tests for Specified Microorganisms 〈62〉

The total aerobic microbial count is NMT 1000 cfu/g, and the total combined molds and yeasts count is NMT 100 cfu/g.

6.2 pH 〈791〉

3.0–5.5

6.3 Loss on Drying 〈731〉

Sample: 1.0 g of Dispersion

Analysis: Dry the Sample at 110° for 5 h.

Acceptance criteria: 68.5%–71.5%

6.4 Coagulum Content

Sample: 100 g of Dispersion

Analysis: Accurately weigh a stainless steel sieve with 45-µm openings or a suitable single-woven wire cloth with a mesh width of 45 µm, and filter the Sample through it. [Note—Suitable single-woven wire cloth mesh meets the requirements set in ISO 9044.] Wash the sieve or the cloth with distilled water until a clear filtrate is obtained, and dry the sieve or the cloth to constant weight at 100°–105°.

Acceptance criteria: The weight of the residue is NMT 500 mg (0.5%).

7 ADDITIONAL REQUIREMENTS

Packaging and Storage: Preserve in tight containers at a temperature below 25°. Protect from freezing.

Labeling: Label it to indicate the amounts of povidone and sodium lauryl sulfate.

USP Reference Standards 〈11〉

USP Polyvinyl Acetate Dispersion RS