Format
Sort by
Items per page

Send to

Choose Destination

Search results

Items: 1 to 50 of 62

1.

Simultaneous separation of small interfering RNA and lipids using ion-pair reversed-phase liquid chromatography.

Li L, Foley JP, Helmy R.

J Chromatogr A. 2019 Sep 13;1601:145-154. doi: 10.1016/j.chroma.2019.04.061. Epub 2019 Apr 27.

PMID:
31072602
2.

Prevalence of Medication Nonadherence to Co-medication Compared to Immunosuppressants in Heart Transplant Recipients: Findings From the International Cross-sectional BRIGHT Study.

Helmy R, Scalso de Almeida S, Denhaerynck K, Berben L, Dobbels F, Russell CL, de Aguiar Roza B, De Geest S; BRIGHT study team.

Clin Ther. 2019 Jan;41(1):130-136. doi: 10.1016/j.clinthera.2018.11.007. Epub 2018 Dec 24.

PMID:
30591285
3.

Enrichment of Relevant Oxidative Degradation Products in Pharmaceuticals With Targeted Chemoselective Oxidation.

Nanda KK, Mozziconacci O, Small J, Allain LR, Helmy R, Wuelfing WP.

J Pharm Sci. 2019 Apr;108(4):1466-1475. doi: 10.1016/j.xphs.2018.10.059. Epub 2018 Nov 2.

PMID:
30395830
4.

In-Use Photostability Practice and Regulatory Evaluation for Pharmaceutical Products in an Age of Light-Emitting Diode Light Sources.

Allain LR, Pierce BC, Wuelfing WP, Templeton AC, Helmy R.

J Pharm Sci. 2019 Mar;108(3):1172-1176. doi: 10.1016/j.xphs.2018.10.003. Epub 2018 Oct 10.

PMID:
30315811
5.

Microbial biotransformation - an important tool for the study of drug metabolism.

Salter R, Beshore DC, Colletti SL, Evans L, Gong Y, Helmy R, Liu Y, Maciolek CM, Martin G, Pajkovic N, Phipps R, Small J, Steele J, de Vries R, Williams H, Martin IJ.

Xenobiotica. 2019 Aug;49(8):877-886. doi: 10.1080/00498254.2018.1512018. Epub 2018 Sep 21.

PMID:
30118378
6.

ESPACOMP Medication Adherence Reporting Guideline (EMERGE).

De Geest S, Zullig LL, Dunbar-Jacob J, Helmy R, Hughes DA, Wilson IB, Vrijens B.

Ann Intern Med. 2018 Jul 3;169(1):30-35. doi: 10.7326/M18-0543. Epub 2018 Jun 26.

PMID:
29946690
7.

The international prevalence and variability of nonadherence to the nonpharmacologic treatment regimen after heart transplantation: Findings from the cross-sectional BRIGHT study.

Helmy R, Duerinckx N, De Geest S, Denhaerynck K, Berben L, Russell CL, Van Cleemput J, Crespo-Leiro MG, Dobbels F; BRIGHT study team.

Clin Transplant. 2018 Jul;32(7):e13280. doi: 10.1111/ctr.13280. Epub 2018 Jun 21.

PMID:
29754400
8.

Accelerated Forced Degradation of Pharmaceuticals in Levitated Microdroplet Reactors.

Li Y, Liu Y, Gao H, Helmy R, Wuelfing WP, Welch CJ, Cooks RG.

Chemistry. 2018 May 23;24(29):7349-7353. doi: 10.1002/chem.201801176. Epub 2018 Apr 30.

PMID:
29653016
9.

Practice patterns to improve pre and post-transplant medication adherence in heart transplant centres: a secondary data analysis of the international BRIGHT study.

Senft Y, Kirsch M, Denhaerynck K, Dobbels F, Helmy R, Russell CL, Berben L, De Geest S; BRIGHT study team.

Eur J Cardiovasc Nurs. 2017 Dec 1:1474515117747577. doi: 10.1177/1474515117747577. [Epub ahead of print]

PMID:
29231747
10.

Using miniature MS system with automatic blood sampler for preclinical pharmacokinetics study.

Pu F, Zhang W, Bateman KP, Liu Y, Helmy R, Ouyang Z.

Bioanalysis. 2017 Nov;9(21):1633-1641. doi: 10.4155/bio-2017-0160. Epub 2017 Nov 2.

11.

Mixed Reality Meets Pharmaceutical Development.

Forrest WP, Mackey MA, Shah VM, Hassell KM, Shah P, Wylie JL, Gopinath J, Balderhaar H, Li L, Wuelfing WP, Helmy R.

J Pharm Sci. 2017 Dec;106(12):3438-3441. doi: 10.1016/j.xphs.2017.08.020. Epub 2017 Sep 1.

PMID:
28870539
12.

Heart transplant centers with multidisciplinary team show a higher level of chronic illness management - Findings from the International BRIGHT Study.

Cajita MI, Baumgartner E, Berben L, Denhaerynck K, Helmy R, Schönfeld S, Berger G, Vetter C, Dobbels F, Russell CL, De Geest S; BRIGHT Study Team.

Heart Lung. 2017 Sep - Oct;46(5):351-356. doi: 10.1016/j.hrtlng.2017.05.006. Epub 2017 Jun 16.

PMID:
28624338
13.

Behavior of Thiophanate Methyl and Propiconazole in Grape and Mango Fruits Under the Egyptian Field Conditions.

Soliman AS, Helmy RM, Nasr IN, Abbas MS, Mahmoud HA, Jiang W.

Bull Environ Contam Toxicol. 2017 May;98(5):720-725. doi: 10.1007/s00128-017-2066-x. Epub 2017 Mar 23.

PMID:
28337501
14.

ESPACOMP Medication Adherence Reporting Guidelines (EMERGE): a reactive-Delphi study protocol.

Helmy R, Zullig LL, Dunbar-Jacob J, Hughes DA, Vrijens B, Wilson IB, De Geest S.

BMJ Open. 2017 Feb 10;7(2):e013496. doi: 10.1136/bmjopen-2016-013496.

15.
16.

Clinical spectrum of primary hyperoxaluria type 1: Experience of a tertiary center.

Soliman NA, Nabhan MM, Abdelrahman SM, Abdelaziz H, Helmy R, Ghanim K, Bazaraa HM, Badr AM, Tolba OA, Kotb MA, Eweeda KM, Fayez A.

Nephrol Ther. 2017 May;13(3):176-182. doi: 10.1016/j.nephro.2016.08.002. Epub 2017 Feb 1.

17.

Mechanistic Study of the Gas-Phase In-Source Hofmann Elimination of Doubly Quaternized Cinchona-Alkaloid Based Phase-Transfer Catalysts by (+)-Electrospray Ionization/Tandem Mass Spectrometry.

Yang RS, Sheng H, Lexa KW, Sherer EC, Zhang LK, Xiang B, Helmy R, Mao B.

J Am Soc Mass Spectrom. 2017 Mar;28(3):452-460. doi: 10.1007/s13361-016-1583-x. Epub 2017 Jan 18.

PMID:
28101849
18.

The Absolute Bioavailability and Effect of Food on the Pharmacokinetics of Odanacatib: A Stable-Label i.v./Oral Study in Healthy Postmenopausal Women.

Zajic S, Rossenu S, Hreniuk D, Kesisoglou F, McCrea J, Liu F, Sun L, Witter R, Gauthier D, Helmy R, Joss D, Ni T, Stoltz R, Stone J, Stoch SA.

Drug Metab Dispos. 2016 Sep;44(9):1450-8. doi: 10.1124/dmd.116.069906. Epub 2016 Jul 11.

PMID:
27402726
19.

Characterization of impurities of HIV NNRTI Doravirine by UHPLC-high resolution MS and tandem MS analysis.

Zhang LK, Yang R, Sheng H, Helmy R, Zheng J, Cao Y, Gauthier DR Jr.

J Mass Spectrom. 2016 Oct;51(10):959-968. doi: 10.1002/jms.3807.

PMID:
27383410
20.

Synthesis of [(14) C]omarigliptin.

Ren S, Gauthier D, Marques R, Helmy R, Hesk D.

J Labelled Comp Radiopharm. 2016 Aug;59(10):386-90. doi: 10.1002/jlcr.3421. Epub 2016 Jun 23.

PMID:
27334864
21.

Use of hydrostatic pressure for modulation of protein chemical modification and enzymatic selectivity.

Makarov AA, Helmy R, Joyce L, Reibarkh M, Maust M, Ren S, Mergelsberg I, Welch CJ.

Org Biomol Chem. 2016 May 11;14(19):4448-55. doi: 10.1039/c6ob00550k.

PMID:
27088756
22.

Moisture determination of tritium tracers utilizing near-infrared spectroscopy.

Marques R, Waterhouse DJ, Helmy R.

J Labelled Comp Radiopharm. 2016 Jun 15;59(7):294-6. doi: 10.1002/jlcr.3394. Epub 2016 Apr 6.

PMID:
27061331
23.

Definitive Metabolite Identification Coupled with Automated Ligand Identification System (ALIS) Technology: A Novel Approach to Uncover Structure-Activity Relationships and Guide Drug Design in a Factor IXa Inhibitor Program.

Zhang T, Liu Y, Yang X, Martin GE, Yao H, Shang J, Bugianesi RM, Ellsworth KP, Sonatore LM, Nizner P, Sherer EC, Hill SE, Knemeyer IW, Geissler WM, Dandliker PJ, Helmy R, Wood HB.

J Med Chem. 2016 Mar 10;59(5):1818-29. doi: 10.1021/acs.jmedchem.5b01293. Epub 2016 Feb 22.

PMID:
26871940
24.

A novel compact mass detection platform for the open access (OA) environment in drug discovery and early development.

Gao J, Ceglia SS, Jones MD, Simeone J, Antwerp JV, Zhang LK, Ross CW 3rd, Helmy R.

J Pharm Biomed Anal. 2016 Apr 15;122:1-8. doi: 10.1016/j.jpba.2016.01.017. Epub 2016 Jan 15.

PMID:
26821286
25.

Combining size-exclusion chromatography with differential hydrogen-deuterium exchange to study protein conformational changes.

Makarov AA, Helmy R.

J Chromatogr A. 2016 Jan 29;1431:224-230. doi: 10.1016/j.chroma.2015.12.069. Epub 2015 Dec 30.

PMID:
26763301
26.

Capture of reactive monophosphine-ligated palladium(0) intermediates by mass spectrometry.

Zheng Q, Liu Y, Chen Q, Hu M, Helmy R, Sherer EC, Welch CJ, Chen H.

J Am Chem Soc. 2015 Nov 11;137(44):14035-8. doi: 10.1021/jacs.5b08905. Epub 2015 Oct 28.

PMID:
26498505
27.

Integration of electrochemistry with ultra-performance liquid chromatography/mass spectrometry.

Cai Y, Zheng Q, Liu Y, Helmy R, Loo JA, Chen H.

Eur J Mass Spectrom (Chichester). 2015;21(3):341-51. doi: 10.1255/ejms.1318.

28.

Online Investigation of Aqueous-Phase Electrochemical Reactions by Desorption Electrospray Ionization Mass Spectrometry.

Lu M, Liu Y, Helmy R, Martin GE, Dewald HD, Chen H.

J Am Soc Mass Spectrom. 2015 Oct;26(10):1676-85. doi: 10.1007/s13361-015-1210-2. Epub 2015 Aug 5.

PMID:
26242804
29.

Enhancing radiolytic stability upon concentration of tritium-labeled pharmaceuticals utilizing centrifugal evaporation.

Marques R, Helmy R, Waterhouse D.

J Labelled Comp Radiopharm. 2015 May 30;58(6):261-3. doi: 10.1002/jlcr.3292. Epub 2015 May 11.

PMID:
25964076
30.

Application of HPLC mixed-mode chromatography in determining radiochemical purity of [(14) C] labeled metformin hydrochloride.

Truong V, Helmy R, Ren S, Schenk D, Waterhouse D.

J Labelled Comp Radiopharm. 2015 Apr;58(4):177-9. doi: 10.1002/jlcr.3264. Epub 2015 Feb 27.

PMID:
25720824
31.

Use of pressure in reversed-phase liquid chromatography to study protein conformational changes by differential deuterium exchange.

Makarov AA, Schafer WA, Helmy R.

Anal Chem. 2015 Feb 17;87(4):2396-402. doi: 10.1021/ac5043494. Epub 2015 Feb 4.

PMID:
25620238
32.

Organic chemistry. Nanomole-scale high-throughput chemistry for the synthesis of complex molecules.

Buitrago Santanilla A, Regalado EL, Pereira T, Shevlin M, Bateman K, Campeau LC, Schneeweis J, Berritt S, Shi ZC, Nantermet P, Liu Y, Helmy R, Welch CJ, Vachal P, Davies IW, Cernak T, Dreher SD.

Science. 2015 Jan 2;347(6217):49-53. doi: 10.1126/science.1259203. Epub 2014 Nov 20.

33.

Coupling of ultrafast LC with mass spectrometry by DESI.

Cai Y, Liu Y, Helmy R, Chen H.

J Am Soc Mass Spectrom. 2014 Oct;25(10):1820-3. doi: 10.1007/s13361-014-0954-4. Epub 2014 Jul 15.

PMID:
25023648
34.

Chromatographic resolution of closely related species: drug metabolites and analogs.

Regalado EL, Helmy R, Green MD, Welch CJ.

J Sep Sci. 2014 May;37(9-10):1094-102. doi: 10.1002/jssc.201400038. Epub 2014 Apr 10.

PMID:
24596023
35.

Development of an automated system for preparation of liquid scintillation counting samples for radiolabeled pharmaceuticals.

Marques R, Bernardoni F, Pollack S, Helmy R.

J Labelled Comp Radiopharm. 2014 Mar;57(3):121-4. doi: 10.1002/jlcr.3156. Epub 2013 Dec 11.

PMID:
24327404
36.

Design and application of an easy to use oligonucleotide mass calculation program.

Yang J, Leopold P, Helmy R, Parish C, Arvary B, Mao B, Meng F.

J Am Soc Mass Spectrom. 2013 Aug;24(8):1315-8. doi: 10.1007/s13361-013-0643-8. Epub 2013 Jun 6.

PMID:
23740032
37.

Discovery of a stable molecular complex of an API with HCl: a long journey to a conventional salt.

Peresypkin A, Variankaval N, Ferlita R, Wenslow R, Smitrovich J, Thompson K, Murry J, Crocker L, Mathre D, Wang J, Harmon P, Ellison M, Song S, Makarov A, Helmy R.

J Pharm Sci. 2008 Sep;97(9):3721-6. doi: 10.1002/jps.21264.

PMID:
18240276
38.

Improving sensitivity in chiral supercritical fluid chromatography for analysis of active pharmaceutical ingredients.

Helmy R, Biba M, Zang J, Mao B, Fogelman K, Vlachos V, Hosek P, Welch CJ.

Chirality. 2007 Nov;19(10):787-92.

PMID:
17722016
39.

Development of a gradient elution preparative high performance liquid chromatography method for the recovery of the antibiotic ertapenem from crystallization process streams.

Sajonz P, Vailaya A, Sudah O, McPherson L, Capodanno V, Natishan TK, Helmy R, Antia FD.

J Chromatogr A. 2006 Sep 8;1126(1-2):365-72. Epub 2006 Jun 2.

PMID:
16735042
40.

Identification of a trace colored impurity in drug substance by preparative liquid chromatography and mass spectrometry.

Wang P, Shi YJ, Helmy R, Reamer R, Vailaya A.

Rapid Commun Mass Spectrom. 2005;19(24):3749-54.

PMID:
16308847
41.

Wetting in hydrophobic nanochannels: a challenge of classical capillarity.

Helmy R, Kazakevich Y, Ni C, Fadeev AY.

J Am Chem Soc. 2005 Sep 14;127(36):12446-7.

PMID:
16144365
42.

Exploiting pH mismatch in preparative high-performance liquid chromatographic recovery of ertapenem from mother liquor streams.

Vailaya A, Sajonz P, Sudah O, Capodanno V, Helmy R, Antia FD.

J Chromatogr A. 2005 Jun 24;1079(1-2):80-91.

PMID:
16038294
43.

Liquid chromatography-mass spectrometry using the hydrogen/deuterium exchange reaction as a tool for impurity identification in pharmaceutical process development.

Novak TJ, Helmy R, Santos I.

J Chromatogr B Analyt Technol Biomed Life Sci. 2005 Oct 25;825(2):161-8. Epub 2005 Jun 28.

PMID:
15990368
44.

Thermal stability of organic monolayers chemically grafted to minerals.

McElwee J, Helmy R, Fadeev AY.

J Colloid Interface Sci. 2005 May 15;285(2):551-6.

PMID:
15837471
46.

Reaction of organosilicon hydrides with solid surfaces: an example of surface-catalyzed self-assembly.

Helmy R, Wenslow RW, Fadeev AY.

J Am Chem Soc. 2004 Jun 23;126(24):7595-600.

PMID:
15198607
47.

Excited-state acid-base chemistry: evidence for a dissociative excited state.

Fan J, Helmy R, Kassis A, Grunseich A, Mangubat P, Hicks C, Stevens N, Gafney HD.

Inorg Chem. 2003 Apr 21;42(8):2486-8.

PMID:
12691552
48.

Characterization and quantitation of aprepitant drug substance polymorphs by attenuated total reflectance fourier transform infrared spectroscopy.

Helmy R, Zhou GX, Chen YW, Crocker L, Wang T, Wenslow RM Jr, Vailaya A.

Anal Chem. 2003 Feb 1;75(3):605-11.

PMID:
12585491
50.

Comparative pharmacological study of the neuromuscular blocking action of some antibiotics.

Zaki MA, Sharaf EM, Mosaad B, Eskander R, Helmy R, El-Domiaty C.

J Egypt Med Assoc. 1976;59(3-4):337-67. No abstract available.

PMID:
1032151

Supplemental Content

Support Center