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Ram B. Gupta

Ram B. Gupta is a Professor of Chemical Engineering at Auburn University, Alabama. He has published numerous research papers and holds several patents on nanomedicine and supercritical fluid technology and is the recipient of the James A. Shannon Director’s Award (1998) from the National Institutes of Health (1998), Young Faculty Career Enhancement Award (1997) from Alabama NSF-EPSCoR, Junior and Senior Research Awards (1998, 2002) from Auburn Alumni Engineering Council, and Science and Engineering Award (2002-2004) from DuPont.

He serves on the editorial boards of Nanomedicine: Nanotechnology, Biology and Medicine, Journal of Biomedical Nanotechnology, and advisory board of Industrial & Engineering Chemistry Research. In addition, he is a consultant to various companies on nanoparticle technology.

Prof. Gupta is involved in the production of pharmaceutical nanoparticles since past 10 years. In recent book, Nanoparticle Technology for Drug Delivery (Taylor & Francis, New York, 2006), Gupta describes the latest development on the engineering and technology aspects. Nanoparticles and microparticles offer unique properties that arise from their small size, large surface area, and the interactions of phases at their interfaces, and are attractive for their potential to improve performance of pharmaceuticals, neutraceuticals, and other high-value-added materials. Over past two decades, supercritical carbon dioxide (above 31.1 oC and 73.7 bar pressure) has emerged as a medium for the formation of micro- and nano-particles of pharmaceutical compounds, due to the its adjustable solvent properties, high diffusivity, non-flammability, and non-toxicity. Depending upon the solubility in supercritical CO2, two classes of processes have emerged: (a) rapid expansion of supercritical solution (RESS) for CO2 soluble materials, and (b) supercritical antisolvent (SAS) for CO2-insoluble materials.

In RESS process, the drug material is first dissolved in supercritical CO2 and then expanded through a nozzle to rapidly precipitate as particles. Since the expansion occurs as fast as the speed of sound, the material comes out as small microparticles. But due to the limited solubility of drugs in supercritical CO2, RESS process had limited utility, so far. In Gupta’s recently developed RESS-SC process [Industrial & Engineering Chemistry Research (2005), 44, 7380-7387] by using menthol solid co-solvent, the solubility has been enhanced by several hundred fold. The presence of the solid cosolvent also hinders the particle growth; hence the particles in nanometer size range are easily obtained. Menthol is later removed by sublimation, yielding pure drug nanoparticles.

In SAS process, the drug material is first dissolved in an organic solvent. The solution is then injected into supercritical CO2, resulting in the extraction of solvent by supercritical CO2 and precipitation of the material. Since, the speed of extraction is fast due to the high (gas-like) diffusivity of supercritical CO2, the small microparticles of the material are obtained. Dr. Gupta has further enhanced the extraction speed by ultrasonic mixing which results in nanoparticles [US Patent 6,620,351; September 16, 2003]. In the new process, the particle size is easily controlled by the extent of ultrasonic power supplied. The strong extraction ability of supercritical CO2 allows the production of pure drug nanoparticles, free of any residual solvent or additives.

Education

He received the B.E. degree (1987) from Indian Institute of Technology, Roorkee, India, the M.S. degree (1989) from the University of Calgary, Canada, and the Ph.D. degree (1993) from the University of Texas at Austin, all in chemical engineering.

Books

Gupta, R.B.; Shim, J.J., Solubility in Supercritical Carbon Dioxide; CRC Press (2007)

Gupta, R.B.; Kompella, U.B., Nanoparticle Technology for Drug Delivery; Informa (2006)

Important Articles

Gupta, R.B.; Chattopadhyay, P. Method of forming nanoparticles and microparticles of controllable size using supercritical fluids with enhanced mass transfer, US Patent 6,620,351; September 16, 2003.

Ranjit Thakur and Ram B. Gupta, Rapid expansion of supercritical solution with solid cosolvent (RESS-SC) process: Formation of 2-aminobenzoic acid nanoparticles, Journal of Supercritical Fluids, (2006), 37, 307-315

Thakur, Ranjit; Gupta, Ram B.. Formation of phenytoin nanoparticles using rapid expansion of supercritical solution with solid cosolvent (RESS-SC) process. International Journal of Pharmaceutics (2006), 308(1-2), 190-199.

Thote Amol J; Gupta Ram B Formation of nanoparticles of a hydrophilic drug using supercritical carbon dioxide and microencapsulation for sustained release. Disease-a-month : DM (2005), 51(6), 362-73.

Thakur, Ranjit; Gupta, Ram B. Rapid Expansion of Supercritical Solution with Solid Cosolvent (RESS-SC) Process: Formation of Griseofulvin Nanoparticles. Industrial & Engineering Chemistry Research (2005), 44(19), 7380-7387.

Thakur, Ranjit; Gupta, Ram B. Supercritical CO2 Based Silica Coating of Gold Nanoparticles Using Water-in-Oil Microemulsions. Industrial & Engineering Chemistry Research (2005), 44(9), 3086-3090.

Thakur, R.; Gupta, Ram B. “Production of Hydrocortisone Micro- and Nano-particles using Supercritical Antisolvent with Enhanced Mass Transfer, Chem. Eng. Comm., 193:293–305, 2006.

Louvier-Hernández, José F.; Luna-Bárcenas G.; Thakur, R.; Gupta, Ram B. “Formation of chitin nano-fibers by supercritical antisolvent,” Journal of Biomedical Nanotechnology, vol 1, pages 1-6, January 2005.

Thote, A.; Gupta, Ram B. “Formation of Nanoparticles of a Hydrophilic Drug using Supercritical CO2 and Microencapsulation for Sustained Release,” Nanomedicine: Nanotechnology, Biology and Medicine, 1, 85-90, 2005.

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