Abstract：
:A tadalafil analogue was detected for the first time during the screening of a health supplement for undeclared sexual enhancement drugs. The compound had been isolated and purified by preparative high-pressure liquid chromatography (HPLC). Its chemical structure was elucidated using high-resolution mass spectrometry (HRMS), electrospray ionization tandem mass spectrometry (ESI-MS/MS) and nuclear magnetic resonance (NMR) spectroscopy. The compound had a protonated molecular ion at m/z 444 with a chemical formula of C26H25N3O4. The data obtained from the MS analysis of the compound suggested that the N-methyl group on the piperazinedione moiety of tadalafil was substituted with a -C5H9 group. Analysis using NMR was performed and the -C5H9 group was characterized as a cyclopentyl moiety. The analogue was named N-cyclopentyl nortadalafil.
journal_name
J Pharm Biomed Analjournal_title
Journal of pharmaceutical and biomedical analysisauthors
Xu Y,Kee CL,Ge X,Low MY,Koh HLdoi
10.1016/j.jpba.2015.08.005subject
Has Abstractpub_date
2016-01-25 00:00:00pages
235-241eissn
0731-7085issn
1873-264Xpii
S0731-7085(15)30103-5journal_volume
118pub_type
杂志文章abstract：:Clara cell secretory protein (CC16) is a 16kDa protein secreted by Clara cells in the lining fluid of bronchiolar and bronchial epithelium. CC16 presents several biologic properties, and has been shown to have immunomodulatory and anti-inflammatory activity. It may play a role in controlling inflammation in the airway...
journal_title：Journal of pharmaceutical and biomedical analysis
pub_type： 杂志文章
doi：10.1016/S0731-7085(03)00570-3
更新日期：2004-03-01 00:00:00
abstract：:The application of strong cation exchange (SCX) HPLC to the analysis of drugs in plasma, tissue and rodent feed is presented. This approach is shown to give useful separations allowing the separation of physiochemically diverse compounds in a simple isocratic system. The SCX columns are not as robust as standard rever...
journal_title：Journal of pharmaceutical and biomedical analysis
pub_type： 杂志文章
doi：10.1016/s0731-7085(98)00085-5
更新日期：1998-09-01 00:00:00
abstract：:A micellar electrokinetic capillary chromatography method was developed for the separation and determination of aliphatic congeners of bis(amidinohydrazones) in standard solution. Eight bis(amidinohydrazones) could be determined in less than 15 min at an applied voltage of 22 kV, using 0.05 M sodium phosphate as buffe...
journal_title：Journal of pharmaceutical and biomedical analysis
pub_type： 杂志文章
doi：10.1016/0731-7085(92)80081-w
更新日期：1992-08-01 00:00:00
abstract：:Simple, sensitive and rapid spectrofluorimetric and derivative absorption spectrophotometric procedures are described for the accurate determination of loperamide hydrochloride. The spectrofluorimetric method involves the measurement of the fluorescence of the compound in an ethanol-sulphuric acid mixture (90:10, v/v)...
journal_title：Journal of pharmaceutical and biomedical analysis
pub_type： 杂志文章
doi：10.1016/0731-7085(95)01116-3
更新日期：1995-05-01 00:00:00
abstract：:A simple high-performance liquid chromatographic method was developed to study the pharmacokinetics of osthole in rat plasma. After addition of an internal standard (paeonol), plasma was deproteinized by acetonitrile for sample clean-up. The drugs were separated on a reversed-phase column and detected by UV absorption...
journal_title：Journal of pharmaceutical and biomedical analysis
pub_type： 杂志文章
doi：10.1016/0731-7085(95)01692-9
更新日期：1996-04-01 00:00:00
abstract：:Eprinomectin is a potent anthelmintic compound that kills certain parasitic nematodes and arthropods of cattle. A sensitive and automated bioanalytical assay was developed for quantitation of eprinomectin in bovine plasma in support of clinical development of eprinomectin for use in all classes of cattle. This assay d...
journal_title：Journal of pharmaceutical and biomedical analysis
pub_type： 杂志文章
doi：10.1016/s0731-7085(97)00183-0
更新日期：1998-04-01 00:00:00
abstract：:The urinary excretion of 2-hydroxyphenylacetic acid (2HPAA) was studied in human volunteers after oral and parenteral doses of coumarin. The presence of 2HPAA in the urine was confirmed by gas chromatography mass spectroscopy (GC MS). Mass spectra of reference material and samples are presented. The determination of 2...
journal_title：Journal of pharmaceutical and biomedical analysis
pub_type： 杂志文章
doi：10.1016/s0731-7085(97)00224-0
更新日期：1998-07-01 00:00:00
abstract：:A high performance liquid chromatography coupled with atomic fluorescence spectrometry method for the determination of thimerosal (sodium ethylmercury thiosalicylate, C9H9HgNaO2S), ethylmercury, and inorganic mercury is proposed. Mercury vapor is generated by the post-column reduction of mercury species in formic acid...
journal_title：Journal of pharmaceutical and biomedical analysis
pub_type： 杂志文章
doi：10.1016/j.jpba.2014.09.011
更新日期：2015-03-15 00:00:00
abstract：:In the present study two methods based on liquid chromatography with diode array detection (HPLC-DAD) coupled to an electrospray ionisation (ESI-MS) interface were developed for the determination of constituents in the tinctures (60%, v/v, DER 1:5) of turmeric (Curcuma longa L.) and Devil's claw (Harpagophytum procumb...
journal_title：Journal of pharmaceutical and biomedical analysis
pub_type： 杂志文章
doi：10.1016/j.jpba.2011.02.029
更新日期：2011-06-01 00:00:00
abstract：:A rapid difference spectrophotometric assay of 5-hydroxymethylfurfuraldehyde (5-HMF) in certain degraded syrups is described. The method involves the measurement of the difference absorbance at 340 nm of the isonicotinoyl hydrazone of 5-HMF, formed at room temperature in an acidic solution of isoniazid, relative to an...
journal_title：Journal of pharmaceutical and biomedical analysis
pub_type： 杂志文章
doi：10.1016/0731-7085(88)80030-x
更新日期：1988-01-01 00:00:00
abstract：:In vitro dissolution/release tests are an important tool in the drug product development phase as well as in its quality control and the regulatory approval process. Mucosal drug delivery systems are aimed to provide both local and systemic drug action via mucosal surfaces of the body and exhibit significant differenc...
journal_title：Journal of pharmaceutical and biomedical analysis
pub_type： 杂志文章,评审
doi：10.1016/j.jpba.2017.06.072
更新日期：2018-01-05 00:00:00
abstract：:A micellar electrokinetic chromatography (MEKC) method for the simultaneous determination of four bioactive constituents (morroniside, loganin, paeoniflorin and paeonal) in the Chinese patent medicine Liuwei Dihuang Pills is established. A carrier composed of 0.2M boric acid, 0.02 M sodium dodecyl sulfate (SDS) and 5%...
journal_title：Journal of pharmaceutical and biomedical analysis
pub_type： 杂志文章
doi：10.1016/j.jpba.2007.04.025
更新日期：2007-09-03 00:00:00
abstract：:Cocaine is one of the most worldwide used illicit drugs. We report a magnetic particles-based enzyme-linked immunoassay (mpEIA) method for the rapid and sensitive determination of cocaine (COC) in saliva, urine and serum samples. Under optimized conditions, the limits of detections were 0.09ngmL(-1) (urine), 0.15ngmL(...
journal_title：Journal of pharmaceutical and biomedical analysis
pub_type： 杂志文章
doi：10.1016/j.jpba.2016.03.004
更新日期：2016-06-05 00:00:00
abstract：:As new metabolic pathways of cocaine were recently identified, a high performance liquid chromatography tandem mass spectrometry (LC-MS/MS) method was developed to simultaneously determine cocaine and nine cocaine-related metabolites in whole blood samples. One-step solid phase extraction was used to extract all of th...
journal_title：Journal of pharmaceutical and biomedical analysis
pub_type： 杂志文章
doi：10.1016/j.jpba.2016.11.024
更新日期：2017-02-05 00:00:00
abstract：:The plasma 5,6-dihydrouracil/uracil (UH2/U) ratio is a possible phenotypic marker of dihydropyrimidine dehydrogenase (DPD) activity, hence an index of 5-fluorouracil (5-FU) response and toxicity. Studies have re-affirmed the value of 5-FU and 5,6-dihydro-5-fluorouracil (FUH2) for therapeutic drug monitoring (TDM). How...
journal_title：Journal of pharmaceutical and biomedical analysis
pub_type： 杂志文章
doi：10.1016/j.jpba.2017.04.055
更新日期：2017-08-05 00:00:00
abstract：:Dermal microdialysis (DMD) is a technique capable of determining the percutaneous penetration of drugs from topical formulations intended for local and/or regional activity. Typically, the concentrations of drug collected in dialysates are very low, generally in the ng/ml or even pg/ml range. An additional challenge i...
journal_title：Journal of pharmaceutical and biomedical analysis
pub_type： 杂志文章
doi：10.1016/j.jpba.2008.09.051
更新日期：2009-11-01 00:00:00
abstract：:An automated on-line SPE and innovative fast polarity switch bioanalysis method employing dual-gradient liquid chromatography (DGLC) coupled with mass spectrometry (DGLC-MS/MS) was established and validated for the simultaneous determination of ferulic acid, ligustrazine and ligustilide in rat plasma after administrat...
journal_title：Journal of pharmaceutical and biomedical analysis
pub_type： 杂志文章
doi：10.1016/j.jpba.2013.08.038
更新日期：2014-01-01 00:00:00
abstract：:SU101 or leflunomide, has been studied extensively because of its anti-cancer and immunomodulating properties. The parent isoxazole compound is converted in vitro and metabolized in vivo to an open ring isomeric form, SU0020. Several pharmacological activities have been reported for the parent and metabolite compounds...
journal_title：Journal of pharmaceutical and biomedical analysis
pub_type： 杂志文章
doi：10.1016/s0731-7085(01)00654-9
更新日期：2002-05-15 00:00:00
abstract：:The current therapeutic strategies are based on the design of multifunctional drug candidates able to interact with various disease related targets. Drugs that have the ability to scavenge reactive oxygen species (ROS), beyond their main therapeutic action, may prevent the oxidative damage of biomolecules. Therefore, ...
journal_title：Journal of pharmaceutical and biomedical analysis
pub_type： 杂志文章
doi：10.1016/j.jpba.2015.06.006
更新日期：2015-10-10 00:00:00
abstract：:Liquidambar styraciflua L., ALTINGIACEAE, popularly known as sweet gum or alligator tree, is an aromatic tree with a natural distribution in North America and acclimated in Brazil. In traditional medicine, L. styraciflua L is used for the treatment of stomach disorders, wounds, and coughs. The present study was design...
journal_title：Journal of pharmaceutical and biomedical analysis
pub_type： 杂志文章
doi：10.1016/j.jpba.2019.06.003
更新日期：2019-09-10 00:00:00
abstract：:Detection of higher-order aggregates (HOA) using size-exclusion chromatography (SEC) was found to be variable for a basic protein, using exposed-silanol or diol-silica-based SEC columns. Preparations of the tetrameric biopharmaceutical enzyme Erwinia chrysanthemil-asparaginase (ErA), which has an isoelectric point of ...
journal_title：Journal of pharmaceutical and biomedical analysis
pub_type： 杂志文章
doi：10.1016/j.jpba.2017.03.004
更新日期：2017-05-30 00:00:00
abstract：:The present manuscript deals with a simple and sensitive flow-injection method for the chemiluminescent determination of thiazides. The method is based on the on-line photodegradation and chemiluminescent determination of the resulting photo-fragments. The on-line photodegradation is performed in basic medium by using...
journal_title：Journal of pharmaceutical and biomedical analysis
pub_type： 杂志文章
doi：10.1016/j.jpba.2004.08.020
更新日期：2004-11-19 00:00:00
abstract：:A polarographic study about how three anti-inflammatories, such as Aceclofenac, Tenoxicam and Droxicam behave, using tast polarography (TP) and differential pulse polarography (DPP) was carried out. These studies were always carried out in a media formed by Methanol-Britton-Robinson aqueous buffer (0.1M) (4:96 (v/v)) ...
journal_title：Journal of pharmaceutical and biomedical analysis
pub_type： 杂志文章
doi：10.1016/j.jpba.2004.04.018
更新日期：2004-09-21 00:00:00
abstract：:A new sildenafil analog has been identified in the softgel shell of a dietary supplement. The compound was investigated by UV spectroscopy and high-resolution MS analysis, leading to the proposed structure 1-methyl-5-{5-[2-(4-methylpiperazin-1-yl)acetyl]-2-propoxyphenyl}-3-propyl-1,6-dihydro-7H-pyrazolo[4,3-d]pyrimidi...
journal_title：Journal of pharmaceutical and biomedical analysis
pub_type： 杂志文章
doi：10.1016/j.jpba.2018.08.031
更新日期：2018-11-30 00:00:00
abstract：:Skin permeability of organic compounds depends on their lipophilicity but can also be affected by compounds interactions with specific skin components. A good chromatographic model of percutaneous penetration determined solely by lipophilicity is provided by the immobilized artificial membrane (IAM) columns. To comple...
journal_title：Journal of pharmaceutical and biomedical analysis
pub_type： 杂志文章
doi：10.1016/s0731-7085(96)02009-2
更新日期：1997-06-01 00:00:00
abstract：:The validation of an analytical method for the quantitative determination of erythromycin thiocyanate formulated in an antibiotic preparation for veterinary use was carried out. This method is based on the microbiological method described in the European Pharmacopoeia to analyze erythromycin thiocyanate as a raw mater...
journal_title：Journal of pharmaceutical and biomedical analysis
pub_type： 杂志文章
doi：10.1016/s0731-7085(99)00143-0
更新日期：1999-11-01 00:00:00
abstract：:Chiral separation of 19 pairs of cis-beta-lactam (BL) stereoisomers of pharmacological importance was examined by capillary electrophoresis using cyclodextrin (CD) derivatives. In order to select the most effective conditions separating the highest number of stereoisomers of BLs, single carboxymethyl alpha-, beta- and...
journal_title：Journal of pharmaceutical and biomedical analysis
pub_type： 杂志文章
doi：10.1016/j.jpba.2010.04.026
更新日期：2010-11-02 00:00:00
abstract：:The use of Near-infrared spectroscopy (NIRS) as a fast and non-destructive technique was employed for moisture content (MC) determination in Antibody-drug conjugates (ADCs) in replacement to Karl Fischer (KF) method. The lab analysis of ADCs, high potent medicines, should be performed in conditions ensuring the operat...
journal_title：Journal of pharmaceutical and biomedical analysis
pub_type： 杂志文章
doi：10.1016/j.jpba.2016.09.014
更新日期：2016-11-30 00:00:00
abstract：:Azurin p28 (NSC745104) is a 28 amino acid peptide fragment that inhibits proliferation of human solid and hematological malignancies in vitro and in vivo by reducing proteasomal degradation of oncogene p53. The present study aimed at developing a novel and fast liquid chromatography/tandem mass spectrometry (LC/MS/MS)...
journal_title：Journal of pharmaceutical and biomedical analysis
pub_type： 杂志文章
doi：10.1016/j.jpba.2010.06.006
更新日期：2010-12-01 00:00:00
abstract：:A rapid, specific and very sensitive liquid chromatographic assay using standard ultraviolet detection has been developed to measure cefazolin (CFZ) or ceftriaxone (CFX) in small samples (200 microl) of plasma using either drug as the internal standard for measurement of the other. A rapid extraction was performed usi...
journal_title：Journal of pharmaceutical and biomedical analysis
pub_type： 杂志文章
doi：10.1016/s0731-7085(99)00273-3
更新日期：2000-03-01 00:00:00
