670 AUXILIARY PACKAGING COMPONENTS
Auxiliary packaging components are articles that are used to support or enhance container–closure systems. These articles include, but are not limited to, pharmaceutical coil for containers. The components covered in this chapter must meet the applicable requirements provided and the additional applicable requirements provided in other specified chapters.

PHARMACEUTICAL COIL
Pharmaceutical coil is used as a filling material in multiple-unit containers for solid oral dosage forms to prevent breakage of tablets or capsules during shipment. The filling material should be discarded once the bottle is opened.
Solutions
Iodinated Zinc Chloride Solution— Dissolve 20 g of zinc chloride and 6.5 g of potassium iodide in 10.5 mL of Purified Water. Add 0.5 g of iodine, and shake for 15 minutes. Filter if necessary. Protect from light.
Zinc Chloride–Formic Acid Solution— Dissolve 20 g of zinc chloride in 80 g of an 850 g/L solution of anhydrous formic acid.
1% DuPont Fiber Identification Stain No. 41 Solution— Dissolve 3.8 g of powdered stain in 378.5 mL of deionized water.
Cotton Pharmaceutical Coil
Purified cotton is the hair of the seed of cultivated varieties of Gossypium hirsutum Linné, or of other species of Gossypium (Fam. Malvaceae). It is deprived of fatty matter and bleached, and does not contain more than traces of leaf residue, pericarp, seed coat, or other impurities. Cotton pharmaceutical coil is used in bottles of solid oral dosage forms to prevent breakage.
Identification—
A: When examined under a microscope, each fiber is seen to consist of a single cell, up to about 4-cm long and 40-µm wide, in the form of a flattened tube with thick and rounded walls that are often twisted.
B: When treated with Iodinated Zinc Chloride Solution, the fibers become violet.
C: To 0.1 g of fibers add 10 mL of Zinc Chloride–Formic Acid Solution, heat to 40, and allow to stand for 2 hours, shaking occasionally: the fibers do not dissolve.
D: Weigh about 5 g of fibers, wet with water, and squeeze out the excess. Add fibers to 100 mL of a boiling solution of a 1% DuPont Fiber Identification Stain No. 4 Solution, and gently boil for at least 1 minute. Remove the fibers, rinse well in cold water, and squeeze out the excess moisture: the fibers become green.
Acidity or Alkalinity— Immerse about 10 g of fibers in 100 mL of recently boiled and cooled Purified Water, and allow to macerate for 2 hours. Decant 25-mL portions of the water, with the aid of a glass rod, into each of two dishes. To one portion add 3 drops of phenolphthalein TS, and to the other portion add 1 drop of methyl orange TS. Neither portion appears pink when viewed against a white background.
Fluorescence— Examine a layer about 5 mm in thickness under UV light at 365 nm. It displays only a slight brownish-violet fluorescence and a few yellow particles. It shows no intense blue fluorescence, apart from that which may be shown by a few isolated fibers.
Residual Hydrogen Peroxide Concentration— Place 1 g of fibers in a beaker containing 30 mL of Purified Water, and stir for 3 minutes with a stirring rod. Pour contents into another clean container (do not squeeze sample), or alternatively, remove the fibers from the solution with clean tweezers. Remove a peroxide analytical test strip2 from its container, and immerse the test end into the sample liquid for 2 seconds. Shake to remove the excess liquid, immediately insert the test strip into a suitable reflectometry instrument, and record the reading in mg/kg (ppm), and calculate residual hydrogen peroxide concentration in ppm.
For an alternate method, place 20 g in a beaker, add 400 mL of Purified Water, stir, add 20 mL of 20% sulfuric acid, and stir contents. Titrate with 0.100 N potassium permanganate solution to a faint pink color that remains for 30 seconds. Record the amount of titer, and calculate the concentration in ppm.
NMT 50 ppm is found using either method.
Loss on Drying 731 Dry 5.00 g of fibers in an oven at 105 to constant weight: it loses NMT 8.0% of its weight.
Residue on Ignition 281 Place 5 g of fibers in a porcelain or platinum dish, and moisten with 2 N sulfuric acid. Gently heat the cotton until it is charred, then ignite more strongly until the carbon is completely consumed: NMT 0.20% of residue remains.
Water-Soluble Substances— Place 10.00 g of fibers in a beaker containing 1000 mL of Purified Water, and boil gently for 30 minutes, adding water as required to maintain the volume. Pour the water through a funnel into another vessel, and press out the excess water from the cotton with a glass rod. Wash the cotton in the funnel with two 250-mL portions of boiling water, pressing the cotton after each washing. Filter the combined extract and washings, and wash the filter thoroughly with hot water. Evaporate the combined extract and washings to a small volume, transfer to a tared porcelain or platinum dish, evaporate to dryness, and dry the residue at 105 to constant weight. The residue weighs NMT 0.35%.
Fatty Matter— Pack 10.00 g of fibers in a Soxhlet extractor provided with a tared receiver, and extract with ethyl ether for 4 hours at a rate such that the ether siphons over not less than four times per hour. The ethyl ether solution in the flask shows no trace of blue, green, or brownish color. Evaporate the extract to dryness, and dry at 105 for 1 hour. The weight of the residue does not exceed 0.7%.
Dyes— Pack about 10 g in a narrow percolator, and extract slowly with alcohol until the percolate measures 50 mL. When observed downward through a column 20 cm in depth, the percolate may show a yellowish color, but not a blue or a green tint.
Other Foreign Matter— Pinches contain no oil stains or metallic particles by visual inspection.
Rayon Pharmaceutical Coil
Rayon pharmaceutical coil is a fibrous form of bleached, regenerated cellulose, to be used as a filler in bottles of solid oral dosage forms to prevent breakage. It consists exclusively of rayon fibers except a few isolated foreign fibers may be present.
[note—Rayon pharmaceutical coil has been found to be a potential source of dissolution problems for gelatin capsules or gelatin-coated tablets resulting from gelatin cross-linking. ]
Identification—
A: When treated with Iodinated Zinc Chloride Solution, the fibers become violet.
B: Add 10 mL of Zinc Chloride–Formic Acid Solution to 0.1 g of fibers, heat to 40, and allow to stand for 2 hours, shaking occasionally: the fibers dissolve completely, except for matt rayon fibers where titanium particles remain.
C: Weigh about 5 g of fibers, wet with water, and squeeze out the excess. Add fibers to 100 mL of a boiling solution of a 1% DuPont Fiber Identification Stain No. 4 Solution, and gently boil for at least 1 minute. Remove the fibers, rinse well in cold water, and squeeze out the excess moisture: the fibers become blue-green.
Acidity or Alkalinity, Fluorescence, Fatty Matter, Dyes, and Other Foreign Matter— Proceed as directed under Cotton Pharmaceutical Coil, except to use rayon pharmaceutical coil. Sample weight for fatty matter is 5 g and weight of residue does not exceed 0.5%.
Loss on Drying 731 Dry 5.00 g of fibers in an oven at 105 to constant weight: it loses NMT 11.0% of its weight.
Residue on Ignition 281: NMT 1.50%, determined on a 5.00-g test specimen.
Acid-Insoluble Ash— To the residue obtained in the test for Residue on Ignition, add 25 mL of 3 N hydrochloric acid, and boil for 5 minutes. Collect the insoluble matter on a tared filtering crucible, wash with hot water, ignite, and weigh: the residue weighs NMT 1.25%.
Water-Soluble Substances— Proceed as directed under Cotton Pharmaceutical Coil, except to use rayon pharmaceutical coil. The residue weighs NMT 1.0%.
Polyester Pharmaceutical Coil
Polyester pharmaceutical coil is a white odorless material, to be used as a filler in bottles of solid oral dosage forms to prevent breakage.
Identification—
A: Proceed as directed under Infrared Spectroscopy in the Test Methods section. Determine the IR spectrum from 4000 to 650 cm1 (2.5 to 15 µm). The spectrum obtained from the specimen exhibits major absorption bands only at the same wavelengths as the spectrum of USP Polyethylene Terephthalate RS.
B: Weigh about 5 g of fibers, wet with water, and squeeze out excess. Add fibers to 100 mL of a boiling solution of a 1% DuPont Fiber Identification Stain No. 4 Solution, and gently boil for at least 1 minute. Remove the fibers, rinse well in cold water, and squeeze out the excess moisture: the fibers become pale orange.
Acidity or Alkalinity and Other Foreign Matter— Proceed as directed under Cotton Pharmaceutical Coil, except to use polyester pharmaceutical coil.
Loss on Drying 731 Dry 5.00 g of fibers in an oven at 105 to constant weight: it loses NMT 1.0% of its weight.
Residue on Ignition 281: NMT 0.5%, determined on a 5.00-g test specimen.
Finish on Fibers— The finish on fibers used for processing should comply with FDA food contact regulations.
Test Methods
infrared spectroscopy3
Apparatus: FTIR or a double-beam spectrometer capable of scanning from 4000 to 650 cm1 (2.5 to 15 µm).
Specimen Preparation—
Method 1 (Potassium Bromide Disk)— Use scissors to cut polyester fibers (1 to 3 mg) into short lengths (less than 1 mm long), mix with 200 mg of powdered potassium bromide, and grind in a ball mill for 1 to 2 minutes. Transfer to potassium bromide-disc die, and form a disc.
Method 2 (Melt Film)— Produce film by pressing polyester fibers between TFE-fluorocarbon sheets and place between heated plates.

1  DuPont Fiber Identification Stain No. 4 is available from Pylam Products Co., 2175 East Cedar Street, Tempe, AZ 85281: www.pylamdyes.com.
2  A suitable analysis system consisting of Reflectoquant® peroxide test strips and a RQflex® reflectometry instrument may be obtained from EMD Chemicals Inc., 480 S. Democrat Road, Gibbstown, NJ 08027: www.emdchemicals.com.
3  Additional information on fiber identification methods may be found in “Standard Test Methods for Identification of Fibers in Textiles”. Current version of ASTM Method D276, published by ASTM International, 100 Barr Harbor Drive, P.O. Box C700, West Conshohocken, PA 19428-2959. www.astm.org.
Auxiliary Information— Please check for your question in the FAQs before contacting USP.
Topic/Question Contact Expert Committee
General Chapter Desmond G. Hunt, Ph.D.
Senior Scientific Liaison
1-301-816-8341
(GCPS2010) General Chapters - Packaging Storage and Distribution
USP35–NF30 Page 280
Pharmacopeial Forum: Volume No. 34(6) Page 1533