ABSTRACT
A rapid and reliable analytical method is described for the simultaneous determination of a synthetic progestin norgestimate (NGM), and its metabolites, 17-deacetylnorgestimate (17-DA-NGM), 3-ketonorgestimate (3-keto-NGM) and norgestrel (NGL) in human serum using reversed phase high-performance liquid chromatography (HPLC) with tandem mass spectrometric (MS-MS) detection. The assay was linear over the concentration ranges of 0.1-5.0 ng/ml for 17-DA-NGM and NGL and 0.5-5.0 ng/ml for NGM and 3-keto-NGM. The inter-assay reproducibility was consistently less than 10%. The overall recovery of the analytes ranged from 72 to 92%. Serum profiles following oral administration of norgestimate to female volunteers are presented.
Subject(s)
Chromatography, High Pressure Liquid/methods , Contraceptives, Oral, Synthetic/blood , Mass Spectrometry/methods , Norgestrel/analogs & derivatives , Drug Combinations , Drug Stability , Female , Humans , Levonorgestrel/analogs & derivatives , Levonorgestrel/blood , Molecular Structure , Norgestrel/blood , Oximes , Quality Control , Reproducibility of Results , Sensitivity and SpecificityABSTRACT
Thymopoietin32--36 (TP5) is a synthetic pentapeptide that has the biological activity of its parent molecule, the 49 amino acid thymic hormone thymopoietin. Tritiated thymopoietin32--36 (3 /-TP5) was prepared by reductive tritiation of dibromotyrosyl-TP5. The stability of 3 H-TP5 in human plasma was studied by analyzing samples by thin-layer chromatography at different time points and quantitating the radioactivity associated with TP5 (Arg-Lys-Asp-Val-Tyr) and its tyrosyl-containing breakdown products (Lys-Asp-Val-Tyr, Asp-Val-Tyr, Val-Tyr, Tyr). In plasma (but not in saline) the pentapeptide was rapidly degraded (apparent t1/2 approximately 30 seconds) with the corresponding appearance of radioactivity associated with the other tyrosyl-containing reference compounds. These data imply that the pentapeptide, which is active in vivo, may rapidly trigger changes in responsive cells; sustained circulating levels may not be required for activity.
Subject(s)
Peptide Fragments/blood , Thymopoietins/blood , Thymus Hormones/blood , Adult , Amino Acid Sequence , Chemical Phenomena , Chemistry , Chromatography, Thin Layer , Half-Life , Humans , ThymopentinABSTRACT
Silylation of salicylic acid by hexamethyldisilazane, N,O-bis(trimethylsilyl)acetamide, and N,N-bis(trimethylsilyl)trifluoroacetamide was compared using GLC. The completeness of the reaction, the stability of products, and the reproducibility of results with time were investigated. Different reaction vessels were examined for their reliability and application for a routine assay procedure.
