Emotions can't be adequately expressed in words. The author's acknowledgement is more than what he has expressed here. Indeed the words at my command are not adequate to convey the depth of my feeling and gratitude to my Major Advisor Dr. M. M. Patel, Professor and Head, Principal, C.P. college of Agriculture, member of advisory committee for their encouragement and ever willing help of various kind during the course of investigation. On this occasion words fail to express my profound reverence, heartfelt gratitude and deep seated obligation to my adorable late father "Shri Jitabhai" and my mother"Mrs. Jatanben," my wife "Savita" son "Nirmal" and Daughter "Payal" for their, constant encourgement, blessings, everlasting love and personal sacrifice at every stage of my studies. - DESAI LALJI J.

Allopurinol is poorly water soluble drug used in treatment of gout. Rapid onset of action of allopurinol drug in treatment of gout is required. Solubility is rate limiting step for this drug. To enhance the solubility here solid dispersion and crystal engineering approach was selected and applied. The solubility and dissolution rate of allopurinol can be enhanced by the use of SDs of allopurinol with PVPK30. The solubilization effect of PVPK30, reduction of particle aggregation of the drug, absence of crystallinity, and alteration of the surface properties of the drug particles might be responsible for the enhanced solubility and dissolution rate of allopurinol from its SD. From FTIR spectroscopy, it was concluded that there was no well defined interaction between allopurinol and PVPK30, since no new peaks or shift of peaks could be observed. The absence of an endothermic peak of allopurinol in the DSC thermo grams of SDs with PVPK30showed the conversion of allopurinol from crystalline to amorphous state. It can be concluded that the preparation SDs of allopurinol with Polymer PVPK30 with ratio (1:2) provides a promising way to enhance its solubility and dissolution.

A selective, rapid and sensitive reverse phase ultra- performance liquid chromatography method was developed for the quantitative determination of fexofenadine in human plasma. With carbamazepine as internal standard, sample pretreatment involved a one-step extraction with ethyl acetate from 980 l plasma. The sample was analyzed using 10mM KH2PO4 buffer pH 2.5 and acetonitrile (70:30 v/v) as mobile phase. Chromatographic separation was achieved on an ACQUITY UPLC BEH (C-18) column using isocratic elution. The peak was detected using UV-PDA detector set at 210 nm and the total time for chromatographic separation was 10 min. Linear calibration curves were obtained in the concentration range of 30.09-1805.39 ng/ml with a lower limit of quantification of 30.09 ng/ml. The inter and intra- day precision (RSD) values were below 15% and accuracy (RE) was from 1.55 to 5.51 % at all QC levels. Developed method was found to be accurate, precise, selective and rapid for estimation of fexofenadine in plasma and can be used for pharmacokinetic and bioequivalence studies.

Immunomodulation using medicinal plants can provide an alternative to conventional chemotherapy for a variety of diseases especially when host defense mechanism has to be acquired under the conditions of impaired immune responsiveness. The objective of the present study was to investigate the immunomodulatory potential of aqueous extract of Trapa bispinosa (TBAE) in immunodeficient experimental animals by studying humoral immunity response, delayed type hypersensitivity reaction, macrophase phagocytosis and percent change in neutrophil counts. Further to evaluate antistress activity, wistar rats were subjected to forced swimming endurance test and chronic cold restraint stress. The result of present study suggests that ethanolic fraction of TBAE could stimulate the cellular and humoral response in animals. The anti-stress and adaptogenic activity exhibited by its ethanol fraction in the study further suggests that its ethanolic fraction may useful in the treatment of several disorders caused by stress by its immunostimulating and immunomodulating properties and also enhancing the homeostasis mechanism.