Identification tests for common excipients, carriers and ingredients, reported as conforming or not conforming.
| Tests | Identification of calcium, carbonate, starches, dextrin, corn syrup solids, cellulose derivatives, gums, gelatin, pullulan, magnesium salts, potassium sorbate and sorbitan monolaurate |
|---|---|
| Method | Chemical identification tests, and thin-layer chromatography |
| Results | Reported against the monograph or specification you name, as conforms or does not conform. |
| Price | Quoted per project |
Identification tests confirm that a material is what its label says by reactions or comparisons that are characteristic of it. They answer an identity question and are reported as conforming or not conforming, not as an amount.
We work to the current official USP-NF monograph unless you name another applicable monograph or edition, and run the tests as that document sets them.
Calcium is recognized by characteristic reactions of the calcium ion: in neutral solution it forms a white calcium oxalate precipitate that does not dissolve in acetic acid but does dissolve in hydrochloric acid, and calcium salts give a brief yellowish-red color to a flame. Identification A is the calcium test with that letter in the monograph. We run the identification tests set in the monograph you name, and report the result as conforming or not conforming.
Corn syrup solids are dried glucose syrup: the purified saccharides obtained from corn starch, with most of the water removed. Their identity rests on being a mixture of glucose and glucose polymers with reducing power: US standards set a reducing sugar content (dextrose equivalent) of at least 20 percent, expressed as glucose on a dry basis. We run the identification tests set in the monograph you name, and report the result as conforming or not conforming.
Croscarmellose sodium is a cross-linked, water-insoluble form of carboxymethylcellulose sodium. Characteristic evidence: it does not dissolve in water or organic solvents, it takes up methylene blue from solution and settles as a blue, fibrous mass, its cellulose backbone gives a red-purple color in the 1-naphthol and sulfuric acid reaction, and it passes a test for sodium. We run the identification tests set in the monograph you name, and report the result as conforming or not conforming.
Hydroxypropyl cellulose is a cellulose ether. Characteristic evidence: it swells in water to a clear to opalescent, viscous colloidal solution, and it gives no precipitate with copper or aluminum sulfate, which separates it from carboxymethylcellulose. Its solubility in ethanol depends on the grade. Identification B is the test with that letter in the monograph. We run the identification tests set in the monograph you name, and report the result as conforming or not conforming.
Hypromellose (hydroxypropyl methylcellulose) is a cellulose ether carrying methoxy and hydroxypropoxy groups. Characteristic evidence: it swells in water to a clear to opalescent, viscous colloidal solution, does not dissolve in ethanol, and gives no precipitate with copper or aluminum sulfate, which separates it from carboxymethylcellulose. Identification A, B and C are the three tests with those letters in the monograph. We run the identification tests set in the monograph you name, and report the result as conforming or not conforming.
Carbonates effervesce with acids, releasing carbon dioxide, which turns a calcium hydroxide solution milky; cold solutions of soluble carbonates also turn phenolphthalein red, which bicarbonates do not. We run the identification tests set in the monograph you name, and report the result as conforming or not conforming.
Starch is identified by its granules and its reactions: under the microscope, starch that has not been pregelatinized shows granules whose shape and size reflect the plant source, with a polarization cross in polarized light; starch stains dark blue to red with iodine; and after acid hydrolysis it reduces hot alkaline copper tartrate to a red precipitate. We run the identification tests set in the monograph you name, and report the result as conforming or not conforming.
Dextrins are starch that has been partly broken down, usually by heat with acid. Characteristic evidence: they stain with iodine as starches do, with colors from blue to red depending on how far the starch has been broken down, and after acid hydrolysis they reduce hot alkaline copper tartrate to a red precipitate. We run the identification tests set in the monograph you name, and report the result as conforming or not conforming.
Gelatin is a protein obtained by partial hydrolysis of collagen. Characteristic evidence: it does not dissolve in cold water but swells and softens in it, dissolves in hot water and sets to a gel on cooling, and does not dissolve in ethanol. As a protein it gives a precipitate with picric acid and a turbidity with dilute tannic acid, and it releases ammonia when heated with soda lime. It does not identify the animal source. We run the identification tests set in the monograph you name, and report the result as conforming or not conforming.
Identification covers both parts of the salt. Carbonate: it effervesces with acids, releasing carbon dioxide, which turns a calcium hydroxide solution milky. Magnesium: in solution with ammonium chloride it gives no precipitate with ammonium carbonate, but a white crystalline precipitate forms when sodium phosphate is added. We run the identification tests set in the monograph you name, and report the result as conforming or not conforming.
Magnesium stearate is a mixture of magnesium salts of fatty acids, mainly stearic and palmitic acids, and is practically insoluble in water. Its identity rests on its two parts: the presence of magnesium, and the composition of the fatty acids released from it. We run the identification tests set in the monograph you name, and report the result as conforming or not conforming.
Potassium sorbate is identified by its two parts. It passes a test for potassium (a violet flame color and a white crystalline precipitate with sodium bitartrate), and acidifying a solution of it precipitates sorbic acid, which melts at 132 to 135 °C. The double bonds of sorbate also decolorize bromine. We run the identification tests set in the monograph you name, and report the result as conforming or not conforming.
Pullulan is a neutral glucan produced by the fungus Aureobasidium pullulans, built mainly of maltotriose units. Characteristic evidence: it dissolves in water but not in ethanol, a solution gives a white precipitate with polyethylene glycol 600, and the enzyme pullulanase breaks it down, so a treated solution loses viscosity compared with an untreated one. We run the identification tests set in the monograph you name, and report the result as conforming or not conforming.
Starch is identified by its granules and its reactions: under the microscope, starch that has not been pregelatinized shows granules whose shape and size reflect the plant source, with a polarization cross in polarized light; starch stains dark blue to red with iodine; and after acid hydrolysis it reduces hot alkaline copper tartrate to a red precipitate. We run the identification tests set in the monograph you name, and report the result as conforming or not conforming.
A test applied to tragacanth to detect karaya gum, a different gum that can be present in place of it or mixed with it. The two gums behave differently: karaya swells in 60 percent ethanol and tragacanth does not, and karaya contains glucuronic acid, which tragacanth lacks. It is a purity test on tragacanth, not an identification of karaya gum as a material. We run the test for karaya gum set in the tragacanth monograph you name, and report the result as conforming or not conforming.
Tragacanth is a plant gum. Characteristic evidence: it swells in water to a smooth, stiff, opalescent mucilage but does not swell in 60 percent ethanol; under the microscope it shows angular fragments with layered structure and small starch grains; it gives a precipitate with copper(II) acetate; and its sugars include arabinose, xylose, fucose, galactose and galacturonic acid, without mannose or glucuronic acid. We run the identification tests set in the monograph you name, and report the result as conforming or not conforming.
Xanthan gum dissolves in water but not in ethanol. Its characteristic identity evidence is its interaction with locust bean (carob bean) gum: heated together in water and cooled, the two form a firm, rubbery gel, while xanthan gum alone does not. We run the identification tests set in the monograph you name, and report the result as conforming or not conforming.
Microcrystalline cellulose is purified, partly depolymerized cellulose. Characteristic evidence: it does not dissolve in water, ethanol or dilute mineral acids, and its infrared spectrum matches that of microcrystalline cellulose. We run the identification tests set in the monograph you name, and report the result as conforming or not conforming.
Confirms the identity of sorbitan monolaurate by the USP identification test B, a thin-layer chromatography comparison with a reference.
Send the excipient or ingredient in its original sealed container, labeled with the supplier lot.
Tell us the monograph the material is claimed to meet; we use the current official USP-NF edition unless you name another. We confirm the sample amount at quote.
Questions about a sample or a method, call 360-967-7010 or email [email protected].
