Photo of Croyle

Croyle, Maria A., Ph.D.
Associate Professor
PHR 4.214D

Research Interests

Mouse Liver 4 days after injection. Adeno virus experessing E. coli beta-galactosidase

293 Cells 24 hrs. after infection with adenovirus expressing green flourescent protein.

Representative Capillary Electropherograms of
A) TMPEG (10 mg/ml) and PEG-HD-AD B) 24 H (100% coverage)
C 4 H (90%) D) 2 H (70%) E) 1 H (50%) F) UnPEGylated Ad.

Effect of Agitation and Container/Closure System on Aggregation of Adenovirus

RP-HPLC Chromatograms Showing Peaks of A) Free PEG (blue line)
B) PEG-Ad (50% Modification, green line) C) Unmodified Ad (purple line) and
D) PEG-Ad (100% modification, black line)

Representative Schematic for a Production and Purification Process For Recombinant Adeno-Associated Viruses. Figure made by graduate student, Hong Le

Figure made by graduate student, Hong Le

Electron micrograph of adenovirus capsids lyophilized in a sucrose Formulation. From the cover of the September/October 2003 issue of BioProcessing Journal.


Production, Processing & Physical Stability of Recombinant Viruses

Methods commonly used for large-scale production of recombinant viruses subject the virus to a series of environments (high salt, extreme pH, and temperature) that can significantly compromise virus capsid structure and, in turn, significantly compromise the ability of the virus to bind to cellular receptors and effectively deliver its genetic payload.  Work in the Croyle lab identifies and optimizes formulations to protect virus infectivity and three-dimensional structure during processing and transport, improve uptake and delivery of viruses to cellular targets, prevent degradation of capsid proteins during long-term storage at ambient temperatures.  

These projects are commonly given to students to familiarize them with methods employed in the biotech industry for production of recombinant viruses. Students will evaluate a viral product at each step during production using assays established and validated in the lab to identify potential places where the efficacy and reliability of a product could be compromised. Using basic thermodynamic principles, students can model virus degradation mechanisms in a given situation and rationally develop formulation strategies to preserve virus structure and activity in a number of real-life situations.

Project Funding: Past and Present

Canadian Research and Technology Initiative (CRTI)

Sigma Aldrich

Avigen, Inc.           

Baxter Laboratories

UT Undergraduate Research Fellowships           

Recent Publications

Renteria, S. S., Clemens, C. C. and Croyle, M.A.  2010. Development of a Nasal Adenovirus-Based Ebola Vaccine: Effect of Concentration and Formulation on Adenovirus Stability and Infectious Titer during Actuation from Two Intranasal Delivery Devices.  Vaccine 28(9):2137-2148.

Quick, K. S. Gerding, K. and Croyle, M. A. Role of Container/Closure System and Formulation on Agitation-Induced Aggregation Phenomena in Recombinant Adenoviral Products  BioProcessing  2003 2(5):35-41.

Adadevoh, K. Croyle, M. A., Malarme, D. Bonfils, E. and Bowe, M. A.  A Short Term Field Use and Shipping Stability Study of a Wild Type Ad5 Adenoviral Reference Material.  BioProcessing  2002 1(3):62-69.

Croyle, M.A., Cheng, X. and Wilson, J.M. Development of Formulations that Enhance the Physical Stability of Viral Vectors for Human Gene Therapy   Gene Ther.   2001 8(17):1281-1291.

Croyle, M.A., Cheng, X., Sandhu, A. and Wilson, J.M. Development of Novel Formulations that Enhance Adenoviral-Mediated Gene Expression to the Lung In Vitro and In Vivo.  Molec. Ther.  2001 4(1):22-28.

Recent Presentations at National and International Meetings

Nineteenth Annual Meeting of the American Association of Pharmaceutical Scientists, Baltimore, M.D.  November 7-11, 2004.

Le, H. and Croyle, M.A. Effect of Storage Condition and Formulation on Aggregation of Recombinant Adeno-Associated Virus.
Williamsburg Bioprocessing Foundation Viral Vectors and Vaccines Conference. Las Vegas, Nevada.  November 10-13, 2003.  

Maria Croyle, invited speaker. "Assessment of Aggregation Phenomena in Recombinant Viral Preparations by DLS."


Twelfth Annual Meeting American Association of Gene Therapy, San Diego, C.A.  May 27-30, 2009.

Renteria, S. S., Clemens, C.C., Wonganan, P.W., and Croyle, M. A. Effects of Concentration and Formulation on Adenovirus Stability and Infectious Titer During Actuation from Two Intranasal Delivery Devices  (Poster)

More information about Dr. Croyle
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Last Reviewed: May 5, 2011

Division Information

Mailing Address:
Pharmaceutics Division
College of Pharmacy
The University of Texas
at Austin
2409 University Ave.
Stop A1900
Austin, TX, USA

Email Address: pharmacy


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