Accurately weigh, count, or measure a portion of the test specimen expected to contain the equivalent of not less than 0.15 mg of retinol but containing not more than 1 g of fat. If in the form of capsules, tablets, or other solid, so that it cannot be saponified efficiently by the ensuing instructions, reflux the portion taken in 10 mL of water on a steam bath for about 10 minutes, crush the remaining solid with a blunt glass rod, and warm for about 5 minutes longer. Transfer to a suitable borosilicate glass flask a test specimen, accurately measured, or not less than 5 previously crushed capsules or tablets. Reflux in an all-borosilicate glass apparatus with 30 mL of alcohol and 3 mL of potassium hydroxide solution (9 in 10) for 30 minutes. Add through the condenser 2.0 g of citric acid monohydrate, washing the walls of the condenser with 10 mL of water. Cool, and transfer the solution to a conical separator with the aid of 20 mL of water. Add 4 g of finely powdered sodium sulfate decahydrate.
Extract with one 150-mL portion of ether and then, if an emulsion forms, with three 25-mL portions of ether. Combine the ether extracts, if necessary, and wash by swirling gently with 50 mL of water. Repeat the washing more vigorously with three additional 50-mL portions of water. Transfer the washed ether extract to a 250-mL volumetric flask, and add ether to volume. Transfer a 100.0-mL aliquot of the resulting ether solution to a conical separator, and wash once with 50 mL of potassium hydroxide solution (1 in 33), using alcohol, if necessary, to break any emulsion that forms. Wash by swirling gently with 50 mL of water. Transfer the washed ether extract to a 100-mL volumetric flask, add ether to volume, and mix. Pipet 15.0 mL of the isopropyl alcohol solution into a 50-mL centrifuge tube, add approximately 200 mg of palladium catalyst, stir with a glass rod, and hydrogenate for 10 minutes in a such as is described in the 551, using isopropyl alcohol in the blank tube. Add about 300 mg of chromatographic siliceous earth, stir with a glass rod, and immediately centrifuge until the solution is clear.
Test a 1-mL aliquot of the solution by removing the solvent by evaporation, dissolving the residue in 1 mL of chloroform, and adding 10 mL of : no detectable blue-green color appears. [If a blue-green color appears, repeat the hydrogenation for a longer time period, or with a new lot of catalyst.] Calculate the vitamin A content as follows: in which A is the observed absorbance at 325 nm; L is the length, in cm, of the absorption cell; and C is the amount of test specimen expressed as g, capsule, or tablet in each 100 mL of the final isopropyl alcohol solution, provided that A has a value not less than [A]/1.030 and not more than [A]/0.970, where [A] is the absorbance at 325 nm and is given by the equation: in which A designates the absorbance at the wavelength indicated by the subscript. USP Reference Standards 11— [Use , all- retinyl acetate, for assaying pharmaceutical dosage forms that are labeled to contain retinol or vitamin A ester (retinyl acetate or retinyl palmitate).]
Dissolve an accurately weighed quantity of retinyl palmitate and in hexane to obtain a solution containing about 7.5 µg per mL of each. Dissolve an accurately weighed quantity of in hexane, and dilute quantitatively, and stepwise if necessary, to obtain a solution having a known concentration of about 15 µg of retinyl acetate per mL. (see Chromatography 621)—The liquid chromatograph is equipped with a 325-nm detector and a 4.6-mm × 15-cm column that contains packing L8. The flow rate is about 1 mL per minute. Chromatograph the and record the peak responses as directed for the resolution, between retinyl acetate and retinyl palmitate is not less than 10; and the relative standard deviation for replicate injections is not more than 3.0%. Separately inject equal volumes (about 40 µL) of the and the into the chromatograph, record the chromatograms, and measure the responses for retinyl acetate obtained from the and the peak area for retinyl acetate or retinyl palmitate in the chromatogram of the Calculate the quantity, in mg, of vitamin A as the retinol equivalent (CHO) in the portion of vitamin A taken by the formula
in which 0.872 is the factor used to convert retinyl acetate, obtained from to its retinol equivalent; C is the concentration, in mg per mL, of in the is the dilution factor, in mL, for the and rU and rS are the peak responses of the retinyl ester obtained from the and the respectively. [The molar responses of retinyl acetate and retinyl palmitate are equivalent.] : Lawrence Evans, III, Ph.D., Scientist : Volume No. 30(4) Page 1340The vast majority of multivitamin and nutritional supplements are filled with synthetic or isolated fragments of vitamins, and this is certainly true for beta carotene, the precursor for vitamin A. What most people don’t know are the dangers that come with ingesting synthetic beta carotene. Natural beta carotene is one of the many brightly colored pigments found in fresh fruits and vegetables. This carotenoid serves as a precursor to vitamin A, a vitamin essential for vision, skin health, immune function, and gene transcription (the first step in gene expression).
Because beta carotene converts to vitamin A in the body as needed, it offers all the health benefits of vitamin A without any of the toxicity of vitamin A sourced from high-dose supplements or cod liver oil. Studies on dietary intake of beta carotene from fruits and vegetables show natural beta carotene offers real long-term protective health benefits. Lower risk of Alzheimer’s In the Rotterdam study (JAMA 2002) the dietary intake of beta carotene was associated with a lower risk of Alzheimer’s disease among smokers. Lower risk of breast cancer An extensive analysis in the Journal of the National Cancer Institute (2012) showed high dietary intake of carotenoids—including beta carotene—was strongly associated with a lower risk of breast cancer, particularly estrogen receptor negative (ER-) breast cancer. These health benefits can be attributed to the use of whole foods, where beta carotene is one of many carotenoids in the plant—with all of its necessary co-factors—delivering complete nutrition.
The Finnish Study, a double-blind, placebo-controlled study published in the New England Journal of Medicine gave over 29,000 male smokers beta carotene and vitamin E, to evaluate the cancer-protective benefits of the vitamins. Surprisingly, the study authors discovered a HIGHER incidence of lung cancer (18%) in those receiving supplementation of beta carotene. And total mortality was 8% higher among those who received beta carotene than those who did not. Buried deep within the study methods is the admission that, “The study agents were formulated as synthetic dl-alpha-tocopheryl acetate (50 percent powder) and synthetic beta carotene (10 percent water-soluble beadlets); all formulations were colored with quinoline yellow.” Is it any wonder that people taking synthetic beta carotene have negative health outcomes when the ingredients used to make it include petrochemicals and harsh solvents? When you imagine beta carotene your mind may wander to the image of vegetables such as carrots, sweet potatoes, squash, spinach, broccoli, kale, pumpkin, parsley and peas.
But that is not where synthetic beta carotene comes from. Instead the reality is synthetic beta carotene is manufactured from benzene extracted from acetylene gas (really, we’re not making this up). Benzene is a natural constituent of crude oil, and is one of the most basic petrochemicals. Not only do these substances have no nutritional value, benzene is considered to be a carcinogen or cancer-causing substance. Unfortunately, most supplements don’t tell you if the vitamins listed are synthetic because they are not legally required to do so. Labeling laws allow companies to call a chemical isolate by the same name as the complete nutrition found in whole food, even though they function entirely differently in the body. But there are ways you can tell. For vitamin A, if your supplement label says Vitamin A Palmitate, Retinyl Acetate or Vitamin A Acetate it is ALL synthetic. For beta carotene, unless the whole food source is listed, it is SYNTHETIC. Companies use synthetic vitamins because the ingredients (petrochemicals) are cheap, and because they think they can get away with making consumers think synthetic and food-based supplements are the same.