He he was a Research fellow, Rajasthan University, Jaipur, India (1975-1979). Research Associate, All India Institute of Medical Sciences, New Delhi (1980-1981). Post-doctoral fellow (1989-1991). Suptdg. Chemist at KDMIPE, Dehradun, India ( April 1991- March 2000). Visiting Scientist at UTMB, Galveston, TX (April 2000-Sept. 2003). Suptdg, Chemist at KDMIPE, Dehradun, India (Oct 2003- Aug.2005).