Our Team

Executive Team


Michael J. Butler, PhD (Chief Executive Officer)

Mike has 25 years of experience with science-driven businesses in Europe, the US, and Asia and is motivated to solve the organizational challenges at the interface of science and business. Mike has worked with Xceleron’s investors to transform the company from a research-oriented laboratory on a University campus to its present-day status in the US with a reputation for routinely providing robust analytical data using AMS detection.

Before joining Xceleron, Mike was the President, Scientific Operations, and Chief Scientific Officer with Aptuit. During an acquisition-driven expansion, he consolidated and integrated API, preclinical, formulation, solid-state chemistry, and drug product manufacturing operations. The organization grew from three locations to eight and employed 800+ staff. Mike was a member of the Aptuit-Laurus Board of Directors.

Before Aptuit, he was Group Vice President at MDS Pharma Services where he managed the company’s largest operations and commercial organizations. Ten clinical and chemistry operating units were located in North America and Europe with clients in North America, Europe, and Asia. Prior to MDS, Mike was the Group Director, Business Development for Huntingdon Life Sciences, UK.


Marie Croft, PhD (Director of Scientific Operations)

Marie leads a team of bioanalytical study directors and has an important role in the management of client relationships.   Marie joined Xceleron in 2005, after graduating from De Montfort University, Leicester with a 1st class honours degree in Pharmaceutical Chemistry.  Whilst at Xceleron, Marie has conducted research into AMS microdosing, specifically the use of cassette dosing to identify drug-drug interactions, as well as the combined used of AMS and PET after microdose administration.  She was awarded a PhD from the University of York in 2013.

Marie has 10 years of experience in HPLC+AMS analysis and has been actively involved in the evolution of LC+AMS assay development and has focused on determining best practices for method validation.  She has acted as a Study Director for numerous projects and was one of the architects of the new analytical team at Germantown.  Her interests include the ongoing development of robust analytical methodologies and finding new applications of the technology.


Eric Guarin, BS (AMS Manager)

Eric is in charge of the operation and maintenance of Xceleron’s 250 kV Accelerator Mass Spectrometer.  Since graduating from Rutgers University in 2005 with a Bachelor of Science in Electrical and Computer Engineering, Eric has worked in the field of Accelerator Mass Spectrometry.  Prior to joining Xceleron, Eric spent seven years working for a commercial radiocarbon laboratory focusing on the 24/7 operation and maintenance of four National Electrostatics Corporation Single Stage Accelerator Mass Spectrometers. He joined Xceleron in 2012

Eric has over 8 years of experience working in the field of Accelerator Mass Spectrometry and has worked with five of the seventeen NEC SSAMS systems currently in operation.  He is focused on producing high quality AMS data for the Pharmaceutical, Crop Protection and Specialty Chemical applications of AMS.  His interests include researching different applications of AMS technology and the measurement of different isotopes.


Ricardo Diaz, BS (Graphitization Manager)

Ricky joined Xceleron in 2012 and leads a team of scientists that processes complex biological matrices intended for detection by AMS. His team strives to improve the oxidation and graphitization of a variety of pharmaceutical, crop protection and specialty chemical matrices intended for detection by AMS. Ricky’s process efficiency efforts are grounded in an understanding of the chemistry and physics of complex matrix cleanup and root cause process improvement.

Since graduating from the University of Florida with a BS in Chemistry in 2007, Ricky has specialized in the oxidation and graphitization of complex matrices for detection by AMS. In all he has seven years of experience in the field. His interests include the ongoing improvement on speed and quality of graphite generation for AMS analysis, and scaling production.


R. Alan Brunner, BS (Director of Quality Assurance)

Alan has been with the company since 2012.  He graduated from the University of Scranton with a Bachelor’s of Science degree in Biology in 1994.  Before joining Xceleron, Alan spent 14 years with multiple CROs including Charles River and Taylor Technologies (InVentiv), assuring compliance with GMP, GLP, GCP, and Part 11 regulations, focusing on bioanalytical testing.  With Xceleron, he directs all quality functions including auditing, archiving, and document control.


Board of Directors


Frank Armstrong (Chairman)

Frank Armstrong is an experienced, medically qualified, Pharmaceutical Executive who has worked to Board level in the UK, US, Switzerland and Germany. He currently works as an Independent Advisor, Chairman and Board Member to Life Science Companies through his own consulting company. He previously led Medical and Development organisations at a number of major Pharma companies and has been the CEO of a number of Life Sciences Companies.

He has extensive experience of all aspects of Medical Development and Product Development in large and small company environments where he has led successful product approvals for the US and EU across a range of therapeutic areas. He led major improvement programmes at Merck Serono, Zeneca and Bayer resulting in successful reduction in Development times, improvements in the design and focus of Development programmes and a portfolio building exercise at Bayer increasing portfolio value year on year.

He has been the CEO of 5 Biotechnology companies (public and private) and was CEO of Fulcrum Pharma, a profitable, Professional Services Company, sold at an 83% premium to Private Equity Investors. In 2007 he led the sale of 454 Life Sciences for CuraGen to Roche for $154M.

Frank has experience as Chairman and as Non Executive Director in the UK Switzerland and the USA with private AIM and NASDAQ listed companies and as Chairman of a Charitable Institution. He has experience as a Remuneration Committee Chair and Audit Committee Member. He has moved successfully from large to small and back to large companies in his career and has experience of equity funded Biotech Companies and profitable companies at 454 Life Sciences and Fulcrum Pharma.

Recently he has been responsible as Chairman for a successful NASDAQ listing (Summit), a successful AIM listing (Redx Pharma) and for a $100M investment in Cardiorentis. Companies Frank is working with have raised about $200M in the last year.

He has a very broad contemporary view of the Pharma, Biotechnology and CRO industries from his extensive experience and current appointments and of the charity sector form his involvement with an HIV/AIDS Charity.


Ed Lascelles

Ed joined the corporate brokering department of Charterhouse Securities in 1998, focusing on primary and secondary fundraisings. He worked for ING Barings advising small- and medium-growth companies prior to joining Close Venture Management in 2004 (now Albion Ventures LLP), one of the largest and most successful venture capital trust managers and a subsidiary of Close Brothers Group Plc.


Angus Whiteley

Angus holds a law degree from Pembroke College, Cambridge. He is a co-founder and Managing Director of Solon Ventures, a venture capital company that focuses on UK technology and life sciences companies. Prior to co-founding Solon, he was a director of Thompson Clive & Partners, a venture capital company that invested internationally. Angus sits on a range of Boards in the  technology and life sciences sectors.

Michael J. Butler, PhD (Chief Executive Officer)


Scientific Advisory Board


Dr. Graham Lappin, PhD, FRC

Graham is a visiting Professor of Pharmacology at the University of Lincoln (UK) who specializes in the use of isotopic tracers in chemistry, biochemistry, pharmacology and drug development.  He spent 25 years in the pharmaceutical industry starting with ICI (which became Zeneca and then AstraZeneca) followed by Covance Laboratories. He joined Xceleron in 2001 as Head of Research where he pioneered many applications of Accelerator Mass Spectrometry and is widely published in the field. In 2010 Graham was based at Xceleron’s Maryland facility as Chief Scientific Officer, after which he moved to the University of Lincoln (UK) where he established a BSc program in Pharmaceutical Science, whilst still remaining on Xceleron’s Scientific Advisory Board. In 2014 he established his own consulting company (GLappin Consulting) and is now a scientific advisor for Xceleron. He was a visiting professor at the Medical University of Vienna (Austria) in 2010 and an Adjunct Professor at Duke University School of Medicine (North Carolina, USA) from 2012 to 2014. He is a member of the Scientific Advisory Board on the Human Regenerative Map Project at the Karolinska Institutet (Sweden), an Emeritus Member of the American Society for Pharmacology and Therapeutics as well being on the editorial advisory panel for the journal Bioanalysis. Graham has published two textbooks: 1) Lappin and Temple, Radiotracers in Drug Development (2006) CRC Press, Taylor and Francis,  (2) Lappin Vllasaliu Fundamentals of ADME Future Science – due for publication later in 2015.


Professor Joseph P. Balthasar

Joseph is Professor of Pharmaceutical Sciences at the State University of New York at Buffalo. He received a B.S. in Pharmacy (1991) and a PhD in Pharmaceutics (1996) from the University at Buffalo. Prior to joining the faculty of the University as an Assistant Professor in 1999, Professor Balthasar served as a Clinical Assistant Professor of Pharmaceutics at the University at Buffalo from 1996-1997 and, from 1997-1999, as an Assistant Professor of the Department of Pharmaceutics and Pharmaceutical Chemistry at the University of Utah. Professor Balthasar’s research, which is funded by the National Institutes of Health, utilizes pharmacokinetic and pharmacodynamic analyses to guide the development of new therapies. Current research focuses on the development of drug targeting strategies to improve the selectivity of cancer chemotherapy and on the development of new immunotherapies for the treatment of humoral autoimmune diseases.


Dr. Stuart Best, PhD

Stuart completed his PhD at the School of Pharmaceutical Sciences, University of Strathclyde. He has a degree in Pharmacy from the University of Strathclyde and is on the register of the Pharmaceutical Society of Great Britain.

Stuart is currently Head of Analytical and DMPK at drug innovator RedxOncology.  He has over 20 years of experience spanning regulated bioanalytical investigations and drug discovery ADME screening for multi-national pharmaceutical companies and Contract Research Organizations. His career is distinguished by progressive applications of newer analytical technologies to characterize an expanding and ever more complex chemical space, specifically in the support of pharmacokinetics and AME.

Prior to RedxOncology, Stuart was VP of Analytical Operations Xceleron, a company specializing in the application of accelerator mass spectrometry to shorten the drug development trajectory. Stuart was with Merck in Scotland where he spent seven years with Organon then Schering-Plough. He acted as bioanalytical site lead and supported critical ADME and pharmacology investigations, including analysis of endogenous compounds. Stuart’s team employed a range of sample preparation and detectors, including parallel columns systems, UPLC, linear ion trap, and QToF systems. Stuart also spent time with Charles River (Inveresk Research) and Bioanalytical Analytical Systems. Most of his analytical time during this period was with LC-MS/MS, GC-MS systems.


Dr. Dennis Smith, PhD

Dennis worked in the pharmaceutical industry for 32 years after gaining his Ph.D from the University of Manchester. He started his career at Fisons Pharmaceuticals, and over 12 years worked on inhalation, oral, and intravenous compounds. For 20 years he was at Pfizer Global Research and Development, Sandwich, where he was Vice President-Pharmacokinetics, Dynamics and Metabolism. During this 32-year span he helped in the Discovery and Development of eight marketed NCEs.

For the past five years Dennis has been working on a part-time basis in an advisory and academic role. His academic appointments include Visiting Professor at the University of Liverpool and Honorary Professor at the University of Cape Town. His research interests and publications (over 150) span all aspects of Drug Discovery and Development particularly where drug metabolism knowledge can affect the design of safer and more efficacious drugs. For many years he has promoted the concepts of physicochemical properties of molecules and their impact on the absorption, distribution, and clearance of drugs. His recent articles provide a balanced view of the discovery, development, and use of medicines; topics range from communicating the risks and benefits of medicines and what biomedical innovation means for the future of health care. Others have commented on the role of metabolites in drug safety, the misunderstandings around protein binding, new ways of evaluating toxicokinetics, why metabolites circulate, and the use of AMS technology. He has co-authored three book. An Introduction to Pharmacokinetics was widely adopted as a reference book for many university courses; Pharmacokinetics and Metabolism in Drug Design has become almost a “best selling” title in Medicinal Chemistry, and a third edition has been published. Reactive Metabolites has just been published, authored with Deepak Dalvie, Amit Kalgutkar and Scott Obach.

He has also edited and been a contributing author in “Metabolism, Pharmacokinetics and Toxicity of Functional Groups-Impact of chemical building blocks on ADMET” (RSC Drug Discovery) and the 3rd edition of the Encyclopedia of Drug Metabolism and Interactions: Vol 3. He is a former committee member of various UK drug metabolism groups including the DMG and PK/UK and member of the editorial board of Xenobiotica, Drug Metabolism Reviews, and Bioanalysis.

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