Department of Agricultural & Biological Engineering
225 South University Street
West Lafayette, IN 47907-2093
B.S., Pharmaceutical Chemistry, National University of Mexico, Mexico City, 1984
M.S., Pharmaceutics, Minor in Physical Chemistry, University of Arizona, Tucson, AZ, 1989
Ph.D., Pharmaceutical Technology, University of Bath, UK., 2001
Assistant Professor – Purdue University (~ 6 years)
Principal Scientist – Bayer Pharmaceuticals (~ 1.5 years)
Senior Scientist – Roche Pharmaceuticals (~ 12 years)
Current Research Areas:
Emphasis on Pharmaceutical, Food and Agricultural Materials: 1) Surface material science including: investigation into surface energy, particle interactions and functionality for dry powders; 2) Surface assessment and stability of processed particles, 3) Phase Transformations, 4) Improved fundamental understanding of Excipients and their performance , 5) Formulation of microparticles for inhalation therapy.
Surface Science in Pharmaceutical Materials is the objective of our research. We are mainly focusing in exploration of and exploiting the physical and chemical factors that influence particle interactions, cohesion-adhesion, in pharmaceutical materials and dosage forms. We apply the emerging advanced high resolution surface analytical technologies available for our studies including IGC, water vapor sorption (VTI), Isothermal microcalorimetry, BET, AFM, spectroscopic and particle size analyzers. All these techniques have provided direct characterization at the microscopic (molecular) level of the surface induced disorder of processed particle, and in some instances, real-time visualization and monitoring of the surface stability by variations in temperature and /or moisture. The influence of water on particle interactions may lead to physical changes and chemical reactivity of composites. These studies are important in that they will lead to better understanding of the behavior and stability of the pharmaceutical materials when exposed to conditions of temperature, moisture and pressure, and eventually finding new approaches to stabilizing materials at the macroscopic (bulk) level for improved functionality of powders and ultimately possible strategies for formulating dosage forms with optimum performance. Recently, we are in the process of starting a major potential new study for the production of solid drug particles, either crystalline or amorphous nature, incorporated in polymers and by making use of etching techniques for surface microfabrication of the materials with greater control of the physico-chemical properties and stability. In general, all these approaches will provide a desired drug form for dry powders for inhalation and topical/transdermal formulations, and for understanding and controlling: materials, formulation and processes to comply with the FDA PAT initiative of quality-by-design. Multidisciplinary collaboration and diversity is highly encouraged and practiced in our group for success.
Activities Materials Surface Group
- Excipient-induced physical changes and excipient-functionality for pharmaceuticals and food fields
- Physical and chemical stability during processing powder blends dry or on wet granulation
- AFM nano-indentation of organic crystalline materials for understanding fracture and determination of slip planes
- Effect of milling on crystalline materials
- Powder technology issues, the behavior of composites or powders and powder blends during development and manufacturing such as content uniformity, segregation and agglomeration, being the result of heterogeneities on surface forces (particle cohesion-adhesion).
- Develop engineered particles by crystallization or precipitation procedures as an alternative approach to formulate dry powders for inhalation