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Bartelt-Hunt SL, Snow DD, Kranz WL, Mader TL, Shapiro CA, Donk SJV, Shelton DP, Tarkalson DD, Zhang TC. Effect of growth promotants on the occurrence of endogenous and synthetic steroid hormones on feedlot soils and in runoff from beef cattle feeding operations. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2012; 46:1352-1360. [PMID: 22242694 DOI: 10.1021/es202680q] [Citation(s) in RCA: 102] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Supplements and growth promotants containing steroid hormones are routinely administered to beef cattle to improve feeding efficiency, reduce behavioral problems, and enhance production. As a result, beef cattle manure will contain both synthetic steroids as well as a range of endogenous steroids including androgens, estrogens, and progestogens. A two-year controlled study was conducted in which beef cattle were administered steroid hormones via subcutaneous implants and feed additives and the occurrence of 16 endogenous and synthetic steroid hormones and metabolites was evaluated in runoff from beef cattle feedlots and in manure and soil collected from feedlot surfaces. Samples were extracted and analyzed using liquid chromatography tandem mass spectrometryfor metabolites of the synthetic androgen trenbolone acetate, 17α-trenbolone, 17β-trenbolone, for the nonsteroidal semisynthetic estrogen agonist, α-zearalanol, and the synthetic progesterone melengesterol acetate, as well as a wide range of endogeneous estrogens, androgens, and fusarium metabolites. Synthetic steroids including trenbolone metabolites and melengestrol acetate were detected in fresh manure and in feedlot surface soils from cattle administered synthetic steroids at concentrations up to 55 ± 22 ng/g dry weight (dw) (17α-trenbolone) and 6.5 ± 0.4 ng/g dw (melengesterol acetate). Melengesterol acetate was detected in 6% of runoff samples from feedlots holding cattle administered synthetic steroids at concentrations ranging up to 115 ng/L. The presence of melengesterol acetate in runoff from beef cattle feeding operations has not been previously reported. Synthetic steroids were not detected in manure or runoff from control cattle. A wide range of endogenous hormones were detected in runoff and feedlot surface soils and manure from cattle given synthetic steroids and from control cattle, with no statistically significant differences in concentration. These results indicate that runoff from confined animal production facilities is of environmental and public health concern regardless of the use of growth promotants.
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Reiter M, Walf VM, Christians A, Pfaffl MW, Meyer HHD. Modification of mRNA expression after treatment with anabolic agents and the usefulness for gene expression-biomarkers. Anal Chim Acta 2007; 586:73-81. [PMID: 17386698 DOI: 10.1016/j.aca.2006.10.049] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2006] [Revised: 09/08/2006] [Accepted: 10/30/2006] [Indexed: 10/23/2022]
Abstract
With this feasibility study a first step towards a new monitoring system for hormonal treatments was done. Screening of regulation and function of anabolic sex steroids via modified gene expression of mRNA in various tissues could be a new approach to trace treatments with unknown drugs or newly combined cocktails. In the study, uterus, liver and muscle tissue from 24 cycling heifers were taken after the animals were treated either with Melengestrol Acetate (MGA), Finaplix-H (200 mg Trenbolone Acetate) or Ralgro (36 mg Zeranol) for 56 days. In every treatment group always two heifers were given 1-fold, 3-fold and 10-fold doses of the standard preparation, the control group without any treatment consisted of two animals. The different tissue gene expression profiles were investigated via the candidate gene approach. Totally 57 candidate genes were selected according to their functionality by screening the actual literature and composed to functional groups: angiogenesis, apoptosis, cell cycle, endocrine factors, energy metabolism, inflammatory factors, muscle function, oncogenes, protein metabolism and transcription factors. Gene expression was measured using quantitative real-time RT-PCR (qRT-PCR) technology. From 24 tested candidate genes in the liver, 17 showed a significant regulation. Eight genes were influenced by MGA, 9 by Finaplix-H, and 4 by Ralgro. For the muscle tissue 19 genes were tested with the result that in the neck muscle 11 genes were regulated and in the hind limb muscle 8 genes. In the neck 5 genes were affected by MGA, 6 by Finaplix-H and 3 by Ralgro. Only 2 genes were influenced by MGA in the hind limb muscle. Finaplix-H affected 6 and Ralgro 4 genes. In the uterus 29 target genes were tested and 13 were significantly influenced by the anabolic sex steroids. Under Finaplix-H treatment eight target genes were regulated and Ralgro and MGA showed a significant regulation in four target genes. The highest gene expression changes under anabolic treatment were observed in the uterus. The analyzed genes showed significant regulations but further studies, testing different animal husbandry conditions will be needed to identify meaningful expression patterns for the different tissues. With the investigation of the regulation and possible function of anabolic sex steroids via gene expression, a preparatory work for the development of an expression pattern for drug screening was made.
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Stolker AAM, Zoontjes PW, Schwillens PLWJ, Kootstra PR, van Ginkel LA, Stephany RW, Brinkman UAT. Determination of acetyl gestagenic steroids in kidney fat by automated supercritical fluid extraction and liquid chromatography ion-trap mass spectrometry. Analyst 2002; 127:748-54. [PMID: 12146906 DOI: 10.1039/b201268p] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Acetyl gestagenic steroids are isolated from animal tissues such as bovine kidney fat by automated supercritical fluid extraction (SFE). After the addition of internal standards and sample pretreatment, the analytes are extracted from the matrix by supercritical CO2 and trapped directly in-line on alumina placed in the extraction vessel. The samples are analysed by liquid chromatography combined with ion-trap mass selective detection (LC-MSn). For quantification, deuterated internal standards are added and single ions of the analytes and internal standards are monitored. For confirmation of the identity of the analytes, two transition ions (one MS2 and one MS3) were monitored and the ratios between the ions were calculated and compared with those of standards. The detection capability for the multi-analyte LC-MSn analysis of megestrol acetate (MA), medroxyprogesterone acetate (MPA), chlormadinone acetate (CMA) and melengestrol acetate (MGA) is 0.5 microg kg(-1). The mean within-laboratory reproducibility ranges from 16-19% (%RSD) at a concentration level of 0.5 microg kg(-1) (n = 9). Running the SFE procedure overnight allows the analysis of 24 samples of fat per day.
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Lõhmus M, Kender T. Determination of gestagens in kidney fat by liquid chromatography tandem mass spectrometry. Anal Chim Acta 2007; 586:233-8. [PMID: 17386717 DOI: 10.1016/j.aca.2006.10.052] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2006] [Revised: 09/09/2006] [Accepted: 10/20/2006] [Indexed: 11/30/2022]
Abstract
The use of gestagens in animal fattening is prohibited within the European Union. Recently, the use of spectrometric methods for the detection and confirmation of banned substances was made obligatory. Therefore, conventional high-performance liquid chromatographic (HPLC) methods have been superseded. It has been possible to couple a previously described HPLC method for the determination of acetyl-gestagens in kidney fat to tandem mass spectrometry (LC-MS/MS). The decision limits CCalpha and the detection capability CCbeta are found to be below the minimum required performance limit (MRPL) established for medroxyprogesterone acetate (MPA) at 1 microg kg(-1). The calculated values for CCalpha are as follows: megestrol acetate (MGA)--0.15 microg kg(-1), melengesterol acetate (MLA)--0.15 microg kg(-1), chlormadinone acetate (CMA)--0.37 microg kg(-1) and for medroxyprogesterone acetate (MPA)--0.24 microg kg(-1). The CCbeta values for these compounds have been determined as 0.19, 0.19, 0.47 and 0.32 microg kg(-1), respectively.
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Poole CF, Zlatkis A, Sye WF, Singhawangcha S, Morgan ED. The determination of steroids with and without natural electrophores by gas chromatography and electron-capture detection. Lipids 1980; 15:734-44. [PMID: 7421428 DOI: 10.1007/bf02534027] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
The response of the electron-capture detector to organic compounds is poorly defined, and the steroids are no exception to this observation. For those steroids which are naturally electron-capturing, the structures of the electrophores will be defined. Other steroids can be made electron-capturing by the formation of appropriate derivatives. Some new or infrequently used reagents for this purpose (flophemesyl ethers, t-bulflophemesyl ethers, pentafluorophenylhydrazone derivatives and halogen-substituted aromatic boronic acids) are described.
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Daxenberger A, Meyer K, Hageleit M, Meyer HH. Detection of melengestrol acetate residues in plasma and edible tissues of heifers. Vet Q 1999; 21:154-8. [PMID: 10568006 DOI: 10.1080/01652176.1999.9695011] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/15/2022] Open
Abstract
The aim of this study was to gain knowledge of residue formation after the use of melengestrol acetate (MGA) as a growth-promoting agent. Two Holstein-Friesian heifers each received a daily dose through the feed of 0, 0.5 mg (2 heifers with and without withdrawal each), 1.5 mg or 5.0 mg MGA for 8 weeks. MGA residues in plasma were screened by enzyme immuno-assay (EIA). Concentrations in kidney, liver, and muscle were quantified by liquid-chromatography-mass spectrometry (LC-MS), and in fat by gas chromatography-mass spectrometry (GC-MS). MGA levels in plasma were 40, 128, and 280 ng/L, respectively. Residues accumulated in muscle and kidney (5-fold), liver (20-to-40-fold), and fat (200-fold). After administration of 1.5 mg per day the mean MGA concentration in fat was 29 micrograms/kg and thus violated USA regulations which specify a limit of 25 ppb. Therefore the labelled use of MGA (0.5 mg per day) has to be officially controlled.
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Hageleit M, Daxenberger A, Meyer HH. A sensitive enzyme immunoassay (EIA) for the determination of melengestrol acetate (MGA) in adipose and muscle tissues. FOOD ADDITIVES AND CONTAMINANTS 2001; 18:285-91. [PMID: 11339262 DOI: 10.1080/02652030121010] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
The development of a sensitive screening method of MGA residues in bovine perirenal fat and muscle based on a competitive microtitration plate enzyme immunoassay is described. The samples were extracted with petroleum ether and purified with octadecyl-silica-cartridges. The detection limit for fat was 0.4 ng/g andfor muscle tissue 0.05 ng/g, much lower than requiredfor reliable detection of positive samples. The mean recovery rates of fortified samples amount to 75%, the mean intraassay variations to 7% and the interassay variation to 13%. Determination limits were validated for fat at 2 ng/g and for muscle at 0.1 ng/g. The efficiency of the new screening method was successfully demonstrated by the direct comparison to GC-MS and LC-MS methods performed at natural positive samples originating from an animal experiment in which the labelled dose (0.5 mg per animal and day) with and without a 48 h withdrawal period or 3-fold or 10-fold the amount of MGA, respectively, was fed to Holstein Frisian heifers. In conclusion, this new screening method can be used for sensitive determination of MGA residues in adipose tissues even after low treatment doses or longer withdrawal periods.
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Chichila TM, Edlund PO, Henion JD, Epstein RL. Determination of melengestrol acetate in bovine tissues by automated coupled-column normal-phase high-performance liquid chromatography. JOURNAL OF CHROMATOGRAPHY 1989; 488:389-406. [PMID: 2745630 DOI: 10.1016/s0378-4347(00)82963-1] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
A method has been developed for the determination of melengestrol acetate in bovine tissues at lower levels than previously reported. Liquid-liquid extraction of tissue homogenates provided crude clean-up while final isolation, screening, and quantification was done on-line with an automated, normal-phase, coupled-column high-performance liquid chromatographic system. The chromatographic system included phenyl and silica analytical columns for the purposes of isolation and final separation, respectively. These columns provided a large difference in selectivity when operated under normal-phase conditions which allowed for the efficient isolation of melengestrol acetate from the complex tissue extracts. Mobile phases were composed of hexane and dichloromethane modified with methanol and water. Transfer and enrichment of the analyte from the primary phenyl column to the silica column was via a short (12 mm x 4 mm I.D.) silica column. Regeneration and equilibration of the phenyl column was performed after the injection of each tissue extract and was accomplished simultaneously while analytical separation occurred on the final silica column. Routing of the mobile phases and regeneration solvent was performed with automated switching valves. The total time required for each analysis was 12 min. Quantification is demonstrated using external standards with UV detection at 287 nm. The overall recovery of the method was 86% with a coefficient of variation of 9.84% at the 10 ppb [the American billion (10(9] is used in this article] level in bovine liver extracts.
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Parks OW, Shadwell RJ, Lightfield AR, Maxwell RJ. Determination of melengestrol acetate in supercritical fluid-solid phase extracts of bovine fat tissue by HPLC-UV and GC-MS. J Chromatogr Sci 1996; 34:353-7. [PMID: 8759324 DOI: 10.1093/chromsci/34.8.353] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
A method is developed for the determination of melengestrol acetate in bovine fat tissue at or less than the established tolerance level of 25 ppb. The procedure uses a combination of supercritical fluid extraction (SFE) and solid-phase extraction (SPE) techniques to produce an extract suitable for analysis with either high-performance liquid chromatography with ultraviolet detection or gas chromatography-mass spectrometry. Overall recovery of the analyte from bovine fat tissue is 99.4% with a coefficient of variation of 4.14%. The SFE-SPE procedure uses a total of 12 mL of organic solvent per fat tissue sample versus more than 1.7 L consumed in current extraction procedures.
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Schiffer B, Totsche KU, Jann S, Kögel-Knabner I, Meyer K, Meyer HHD. Mobility of the growth promoters trenbolone and melengestrol acetate in agricultural soil: column studies. THE SCIENCE OF THE TOTAL ENVIRONMENT 2004; 326:225-237. [PMID: 15142778 DOI: 10.1016/j.scitotenv.2004.01.003] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/14/2003] [Revised: 01/12/2004] [Accepted: 01/16/2004] [Indexed: 05/24/2023]
Abstract
There is growing concern about environmentally released man-made chemicals suspected to be responsible for a number of adverse effects on endocrine function in wildlife species and possibly also in humans. Sex hormones are of particular interest due to their regulatory role in developmental processes such as sexual differentiation. Endogenous hormones of human or animal origin as well as exogenous sex steroids used for contraception or as anabolics for farm animals are excreted and reach the environment. We investigated the transport of the synthetic growth promoters trenbolone (TbOH) and melengestrol acetate (MGA) in agricultural soil by means of column experiments with aggregated soil materials (Ap and Bt horizons of a Luvisol). Column effluent concentrations and depth profiles of TbOH and MGA were determined with sensitive enzyme immunoassay systems and HPLC (RP-18), respectively. All procedures were confirmed by liquid chromatography-mass spectrometry. Small amounts of TbOH and MGA passed the columns very quickly. However, both hormones exhibited a high affinity to the organic matter of both horizons leading to a high retardation within the upper layers of the soil columns. Although we cannot deduce whether hormones of animal origin reach the ground water under field conditions, our model experiments show that their transition can be presumed.
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Lange IG, Daxenberger A, Hageleit M, Pfaffl MW, Meyer HHD. Non-invasive screening for treatment of heifers with the anabolic steroid melengestrol acetate (MGA) by feces analysis. J Immunoassay Immunochem 2004; 24:265-72. [PMID: 12953971 DOI: 10.1081/ias-120022936] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
For eight weeks, two heifers each had been orally administered daily doses of 0, 1.5, or 5 mg melengestrol acetate (MGA) in a feed premix. Four heifers received the labeled dose of 0.5 mg/day. Regular feces samples were taken throughout the experiment. A rapid screening method for the determination of MGA in feces was developed, consisting of liquid extraction, clean-up on solid-phase extraction cartridges and quantification by enzyme immunoassay (ELISA). Residues in feces were dose-dependent with mean values of < 0.25, 2.0, 4.4, or 15.4 ng/g for 0, 0.5, 1.5, and 5 mg/day doses, respectively. In contrast to urine analysis, feces analysis appeared to be a suitable means of non-invasive screening before slaughter for surveillance of MGA treatment and verification of its compliance with labeled dosage.
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Andresen MT, Fesser AC. Liquid chromatographic determination of progestogens in animal fat. J AOAC Int 1996; 79:1037-42. [PMID: 8823911] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
A liquid chromatographic method was developed for determination of 3 progestogens-melengestrol acetate, megestrol acetate, and chlormadinone acetate-found in edible tissue at concentrations between 10 and 1000 ppb. These progestogens are commonly used as feed additives to control herd estrus and to improve feed efficiency. Rendered fat was extracted with acetonitrile, washed with hexane, and dried. The remaining lipids were saponified with sodium hydroxide and precipitated with magnesium chloride. The progestogens were extracted from the basic solution with hexane, dried, and cleaned up on a cyanopropyl solid-phase extraction column in the normal-phase mode. The eluate was dried and reconstituted with acetonitrile-water (7 + 3, v/v). Chromatography was performed on a 5 microns high-carbon load C18 column with acetonitrile-water (7 + 3, v/v) at 1 mL/min and UV detection at 291 nm. Recoveries from fortified samples ranged from 84 to 116%. The limit of quantitation was 10 ppb for both beef and pork. The detection limit was 3 ppb.
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Roybal JE. High pressure liquid chromatographic determination of melengestrol acetate in dry feed supplements. JOURNAL - ASSOCIATION OF OFFICIAL ANALYTICAL CHEMISTS 1981; 64:661-4. [PMID: 7240072] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
A high pressure liquid chromatographic (HPLC) method is described for the quantitative determination of melengestrol acetate (MGA) in dry animal feed supplements containing 0.000027-0.000220% MGA (0.125-1.00 mg/lb). Ground feed is Soxhlet-extracted with hexane, and the extract is partitioned from hexane into aqueous methanol and then into methylene chloride, followed by mixed column chromatography. MGA is then quantitated by HPLC. Average recovery of standard MGA through the method at 1.00 ppm (0.454 mg/lb) was 94.8% with a 3.58% standard deviation. Average spike recovery of MGA in fortified feed at 0.100 ppm (0.0454 mg/lb) to 2.00 ppm (0.907 mg/lb) level was 97.8% with a standard deviation of 5.39%. In addition, the method includes a 2-dimensional thin layer chromatographic confirmatory test for MGA.
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Krzeminski LF, Geng S, Cox BL. Determination of melengestrol acetate in bovine tissue: collaborative study. JOURNAL - ASSOCIATION OF OFFICIAL ANALYTICAL CHEMISTS 1976; 59:507-15. [PMID: 1270378] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Seven laboratories collaboratively studied a method for the assay of melengestrol acetate at the 0, 10, and 20 ppb levels in bovine fat, liver, muscle, and kidney. The study included fortification of tissue by each laboratory and analysis of fat samples taken from treated heifers which had endogenous levels of 0, 10, and 20 ppb melengestrol acetate. The multistep cleanup procedure used included extraction, solvent partition, column chromatography, and electron capture gas-liquid chromatographic, determination. Results of the study for muscle, liver, kidney, and fat showed that the method gave satisfactory recoveries and accuracy. In fat, the most critical tissue, recovery was greater than 93%. A statistical comparison of the results reported for fat tissue from treated heifers demonstrated that 5 of the 7 laboratories obtained similar results. The results produced by the method can be expected to be repeatable within and among laboratories. On the basis of the collaborative results the method has been adopted as official first action.
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Evaluation of certain veterinary drug residues in food. WORLD HEALTH ORGANIZATION TECHNICAL REPORT SERIES 2003; 911:i-vi, 1-66, back cover. [PMID: 12592988] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 03/01/2023]
Abstract
This report presents the conclusions of a Joint FAO/WHO Expert Committee convened to evaluate the safety of residues of certain veterinary drugs in food and to recommend maximum levels for such residues in food. The first part of the report considers risk assessment principles and presents the views of the Committee on the FAO/WHO Project to update principles and methods for the risk assessment of chemicals in food. Summaries follow of the Committee's evaluations of toxicological and residue data on a variety of veterinary drugs: three anthelminthic agents (doramectin, ivermectin and tiabendazole), seven antimicrobial agents (cefuroxime, dihydrostreptomycin and streptomycin, lincomycin, neomycin, oxytetracycline and thiamphenicol), four insecticides (cyhalothrin, cypermethrin and alpha-cypermethrin, and phoxim) and one production aid (melengestrol acetate). Annexed to the report is a summary of the Committee's recommendations on these drugs, including Acceptable Daily Intakes and Maximum Residue Limits and further information required.
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Technical Report |
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Davis RA, Koshy KT, Ogilvie ML, Stahl GL, Callahan WA. Electron capture gas chromatographic determination of melengestrol acetate in animal feed supplements. JOURNAL - ASSOCIATION OF OFFICIAL ANALYTICAL CHEMISTS 1972; 55:103-9. [PMID: 4677390] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
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Comparative Study |
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Weigand JL, Dille DS. Determination of melengestrol acetate in feedstuffs with liquid chromatographic preparatory column cleanup and quantitative analysis. JOURNAL - ASSOCIATION OF OFFICIAL ANALYTICAL CHEMISTS 1988; 71:707-9. [PMID: 3417585] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Melengestrol acetate (MGA) is determined by liquid chromatography using a fraction from preparatory LC as a means of sample cleanup for feedstuffs, both dry and liquid. Dry ground feed is Soxhlet extracted with hexane and passed through a 2% deactivated alumina column for initial cleanup. The eluate is evaporated, redissolved in methanol, filtered, and injected onto a preparatory LC column. The fraction containing MGA is separated from the remaining matrix, evaporated to dryness, dissolved in methanol, and quantitated by LC analysis. Liquid supplements are extracted in methanol, and the extract is evaporated to near dryness. The residue is diluted with water, extracted with chloroform, passed through sodium sulfate, and evaporated to dryness. The remaining sample is dissolved in methanol prior to preparative LC and quantitative LC. Recoveries for 2 laboratory-fortified commercial feeds, one dry and one liquid, containing 0.39 and 0.40 mg/lb, were 98.3% +/- 4.4 and 95.8% +/- 4.3, respectively. Results compare favorably with existing methods. Up to a 4-fold time savings was realized by this method without automation.
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Midkiff VC. Report on drugs in feeds. JOURNAL - ASSOCIATION OF OFFICIAL ANALYTICAL CHEMISTS 1974; 57:320. [PMID: 4816500] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
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Davis RA, Kratzer DD, Geng S. Gas-liquid chromatographic determination of melengestrol acetate in cattle feed supplements: collaborative study. JOURNAL - ASSOCIATION OF OFFICIAL ANALYTICAL CHEMISTS 1980; 63:425-43. [PMID: 7430028] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
The assay for melengestrol acetate (MGA) in cattle feed supplements was the subject of a collaborative study using 6 laboratories. Two feed formulations were each fortified with 0, 0.0625, 0.125, 0.500, 1.00, and 1.50 mg MGA/lb of supplement, and each laboratory assayed 4 samples of each level of each formulation by electron capture gas chromatography after liquid-liquid extraction of each sample followed by solvent partition and column chromatography cleanup procedures. Overall recovery was 83.2% with a pooled within-laboratory sample-to-sample standard deviation of 9.5%. This includes the variability due to formulation, batches, days, levels of MGA, samples, and their interactions. Including the collaborators as a source of variance results in an overall standard deviation of 15.0%. The major sources of variability were associated with collaborator, formulation, and level of MGA. Lower than expected recoveries were attributed to difficulty in recovering MGA from samples containing concentrations of MGA below the range of the method and the inadvertent substitution by some laboratories of ethanol-free chloroform for the ethanol-containing reagent grade chloroform specified in the methodology. On the basis of the collaborative results, the method has been adopted as official first action for MGA in cattle feed supplements at concentrations from 0.125 to 1.00 mg MGA/lb.
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