Gregory S. Walker

2.4k total citations
55 papers, 1.6k citations indexed

About

Gregory S. Walker is a scholar working on Molecular Biology, Pharmacology and Spectroscopy. According to data from OpenAlex, Gregory S. Walker has authored 55 papers receiving a total of 1.6k indexed citations (citations by other indexed papers that have themselves been cited), including 21 papers in Molecular Biology, 18 papers in Pharmacology and 14 papers in Spectroscopy. Recurrent topics in Gregory S. Walker's work include Pharmacogenetics and Drug Metabolism (16 papers), Analytical Chemistry and Chromatography (10 papers) and Drug Transport and Resistance Mechanisms (8 papers). Gregory S. Walker is often cited by papers focused on Pharmacogenetics and Drug Metabolism (16 papers), Analytical Chemistry and Chromatography (10 papers) and Drug Transport and Resistance Mechanisms (8 papers). Gregory S. Walker collaborates with scholars based in United States, United Kingdom and Australia. Gregory S. Walker's co-authors include R. Scott Obach, Tim F. Ryder, Raman Sharma, Amit S. Kalgutkar, Martin E. Dowty, Chandra Prakash, Gary Chan, Jinyan Lin, Alfin D. N. Vaz and Sriram Krishnaswami and has published in prestigious journals such as Journal of Medicinal Chemistry, Annals of Oncology and Journal of Pharmaceutical Sciences.

In The Last Decade

Gregory S. Walker

52 papers receiving 1.6k citations

Peers — A (Enhanced Table)

Peers by citation overlap · career bar shows stage (early→late) cites · hero ref

Name	h						Papers	Cites
Gregory S. Walker United States	25	540	533	282	251	209	55	1.6k
Raju Subramanian United States	22	611 1.1×	370 0.7×	270 1.0×	126 0.5×	180 0.9×	75	1.8k
David D. Christ United States	25	537 1.0×	472 0.9×	335 1.2×	401 1.6×	129 0.6×	49	1.9k
Tove Sjögren Sweden	20	698 1.3×	528 1.0×	258 0.9×	172 0.7×	269 1.3×	28	1.8k
Geert Mannens Belgium	25	550 1.0×	749 1.4×	472 1.7×	149 0.6×	153 0.7×	59	2.1k
Jonathan Bauman United States	17	709 1.3×	650 1.2×	325 1.2×	263 1.0×	264 1.3×	28	1.6k
B. Kevin Park United Kingdom	25	751 1.4×	803 1.5×	303 1.1×	373 1.5×	241 1.2×	41	2.6k
Dan A. Rock United States	28	633 1.2×	953 1.8×	721 2.6×	132 0.5×	264 1.3×	68	2.1k
Alfin D. N. Vaz United States	26	1.1k 2.0×	1.0k 1.9×	513 1.8×	326 1.3×	196 0.9×	59	2.7k
S. Cyrus Khojasteh United States	24	627 1.2×	617 1.2×	609 2.2×	154 0.6×	191 0.9×	94	1.6k
Shawn Harriman United States	16	541 1.0×	483 0.9×	238 0.8×	230 0.9×	242 1.2×	29	1.3k

Countries citing papers authored by Gregory S. Walker

Since Specialization

Citations

This map shows the geographic impact of Gregory S. Walker's research. It shows the number of citations coming from papers published by authors working in each country. You can also color the map by specialization and compare the number of citations received by Gregory S. Walker with the expected number of citations based on a country's size and research output (numbers larger than one mean the country cites Gregory S. Walker more than expected).

Fields of papers citing papers by Gregory S. Walker

Since Specialization

Physical SciencesHealth SciencesLife SciencesSocial Sciences

This network shows the impact of papers produced by Gregory S. Walker. Nodes represent research fields, and links connect fields that are likely to share authors. Colored nodes show fields that tend to cite the papers produced by Gregory S. Walker. The network helps show where Gregory S. Walker may publish in the future.

Co-authorship network of co-authors of Gregory S. Walker

This figure shows the co-authorship network connecting the top 25 collaborators of Gregory S. Walker. A scholar is included among the top collaborators of Gregory S. Walker based on the total number of citations received by their joint publications. Widths of edges represent the number of papers authors have co-authored together. Node borders signify the number of papers an author published with Gregory S. Walker. Gregory S. Walker is excluded from the visualization to improve readability, since they are connected to all nodes in the network.

All Works

Sort: Min cites: Since: Top N: Style:

20 of 20 papers shown

Kalgutkar, Amit S., Heather Eng, Alyssa Dantonio, et al.. (2025). Absorption, distribution, metabolism, and excretion tactics toward the expedited discovery and development of the severe acute respiratory syndrome coronavirus-2 main protease inhibitor nirmatrelvir. Drug Metabolism and Disposition. 54(2). 100226–100226.

Dowty, Martin E., Ruolun Qiu, Alyssa Dantonio, et al.. (2024). The Metabolism and Disposition of Brepocitinib in Humans and Characterization of the Formation Mechanism of an Aminopyridine Metabolite. Drug Metabolism and Disposition. 52(7). 690–702. 4 indexed citations

Eng, Heather, Alyssa Dantonio, Eugene P. Kadar, et al.. (2022). Disposition of Nirmatrelvir, an Orally Bioavailable Inhibitor of SARS-CoV-2 3C-Like Protease, across Animals and Humans. Drug Metabolism and Disposition. 50(5). 576–590. 77 indexed citations

Singh, Ravi Shankar Prasad, Gregory S. Walker, Eugene P. Kadar, et al.. (2022). Metabolism and Excretion of Nirmatrelvir in Humans Using Quantitative Fluorine Nuclear Magnetic Resonance Spectroscopy: A Novel Approach for Accelerating Drug Development. Clinical Pharmacology & Therapeutics. 112(6). 1201–1206. 15 indexed citations

Cerny, Matthew A., Amit S. Kalgutkar, R. Scott Obach, et al.. (2020). Effective Application of Metabolite Profiling in Drug Design and Discovery. Journal of Medicinal Chemistry. 63(12). 6387–6406. 33 indexed citations

Ji, Changhua, Mausumee Guha, Xu Zhu, et al.. (2019). Enzalutamide and Apalutamide: In Vitro Chemical Reactivity Studies and Activity in a Mouse Drug Allergy Model. Chemical Research in Toxicology. 33(1). 211–222. 31 indexed citations

Obach, R. Scott, Gregory S. Walker, Raman Sharma, et al.. (2018). Lead Diversification at the Nanomole Scale Using Liver Microsomes and Quantitative Nuclear Magnetic Resonance Spectroscopy: Application to Phosphodiesterase 2 Inhibitors. Journal of Medicinal Chemistry. 61(8). 3626–3640. 24 indexed citations

Stepan, Antonia F., Tuan P. Tran, Christopher J. Helal, et al.. (2018). Late-Stage Microsomal Oxidation Reduces Drug–Drug Interaction and Identifies Phosphodiesterase 2A Inhibitor PF-06815189. ACS Medicinal Chemistry Letters. 9(2). 68–72. 25 indexed citations

Ryder, Tim F., Matthew F. Calabrese, Gregory S. Walker, et al.. (2018). Acyl Glucuronide Metabolites of 6-Chloro-5-[4-(1-hydroxycyclobutyl)phenyl]-1 H -indole-3-carboxylic Acid (PF-06409577) and Related Indole-3-carboxylic Acid Derivatives are Direct Activators of Adenosine Monophosphate-Activated Protein Kinase (AMPK). Journal of Medicinal Chemistry. 61(16). 7273–7288. 18 indexed citations

10.

Brodney, Michael A., Raman Sharma, John T. Lazzaro, Gregory S. Walker, & R. Scott Obach. (2018). Harnessing biosynthesis and quantitative NMR for late stage functionalization of lead molecules: Application to the M1 positive allosteric modulator (PAM) program. Bioorganic & Medicinal Chemistry Letters. 28(11). 2068–2073. 9 indexed citations

11.

Steeg, Evita van de, Frank Schuren, R. Scott Obach, et al.. (2018). An Ex Vivo Fermentation Screening Platform to Study Drug Metabolism by Human Gut Microbiota. Drug Metabolism and Disposition. 46(11). 1596–1607. 31 indexed citations

12.

Thakare, Rhishikesh, Hongying Gao, Rachel E. Kosa, et al.. (2017). Leveraging of Rifampicin-Dosed Cynomolgus Monkeys to Identify Bile Acid 3-O-Sulfate Conjugates as Potential Novel Biomarkers for Organic Anion-Transporting Polypeptides. Drug Metabolism and Disposition. 45(7). 721–733. 38 indexed citations

13.

Obach, R. Scott, Gregory S. Walker, & Michael A. Brodney. (2016). Biosynthesis of Fluorinated Analogs of Drugs Using Human Cytochrome P450 Enzymes Followed by Deoxyfluorination and Quantitative Nuclear Magnetic Resonance Spectroscopy to Improve Metabolic Stability. Drug Metabolism and Disposition. 44(5). 634–646. 23 indexed citations

14.

Zientek, Michael, Theunis C. Goosen, Elaine Tseng, et al.. (2015). In Vitro Kinetic Characterization of Axitinib Metabolism. Drug Metabolism and Disposition. 44(1). 102–114. 30 indexed citations

15.

Walsky, Robert L., R. Scott Obach, Ruth Hyland, et al.. (2012). Selective Mechanism-Based Inactivation of CYP3A4 by CYP3cide (PF-04981517) and Its Utility as an In Vitro Tool for Delineating the Relative Roles of CYP3A4 versus CYP3A5 in the Metabolism of Drugs. Drug Metabolism and Disposition. 40(9). 1686–1697. 74 indexed citations

16.

Zhao, Sabrina X., et al.. (2011). Metabolism of a Dopamine Receptor Partial Agonist in Rats, Including an Unusual N-Dearylation Reaction. Drug Metabolism and Pharmacokinetics. 26(3). 266–279. 1 indexed citations

17.

Shah, Manish B., et al.. (2010). Comparison of In Vitro Metabolism of Ticlopidine by Human Cytochrome P450 2B6 and Rabbit Cytochrome P450 2B4. Drug Metabolism and Disposition. 39(3). 539–550. 21 indexed citations

18.

Walker, Gregory S., Tim F. Ryder, Raman Sharma, Evan B. Smith, & Amy Freund. (2010). Validation of Isolated Metabolites from Drug Metabolism Studies as Analytical Standards by Quantitative NMR. Drug Metabolism and Disposition. 39(3). 433–440. 47 indexed citations

19.

Walker, Gregory S. & Thomas N. O’Connell. (2008). Comparison of LC-NMR and conventional NMR for structure elucidation in drug metabolism studies. Expert Opinion on Drug Metabolism & Toxicology. 4(10). 1295–1305. 19 indexed citations

20.

Roediger, W. E. W., et al.. (1989). Assessment of Salicylate Derivatives for Potential Use in Ulcerative Colitis: Proposal for a New Action of 5-Aminosalicylic Acid?. Pharmacology. 39(1). 39–45. 6 indexed citations

Rankless uses publication and citation data sourced from OpenAlex, an open and comprehensive bibliographic database. While OpenAlex provides broad and valuable coverage of the global research landscape, it—like all bibliographic datasets—has inherent limitations. These include incomplete records, variations in author disambiguation, differences in journal indexing, and delays in data updates. As a result, some metrics and network relationships displayed in Rankless may not fully capture the entirety of a scholar's output or impact.

Explore authors with similar magnitude of impact