Determination of Solubility and Thermophysical Properties of Tetracycline Hydrochloride and Ciprofloxacin Antibiotics in Different Solvents System.

In this research article, we have described to establish a comparison between the solubility of the hydrochloride and non-hydrochlorideforms of ciprofloxacin and tetracycline in relevant solvents. For that purpose the solubility ofciprofloxacin and tetracycline were measured in water, methanol, propanol,and acetone, in the temperature range between 293.20 and 323.20 K for ciprofloxacin and between 288.20and 303.20 K for tetracycline. The solubility of the hydrochloride form in water is about 2 orders of magnitude higherthan those of the respective base forms. In acetone, we see the opposite effect. For methanol and propanolthe influence of the hydrochloride group of the antibiotic on the solubility in the alcohol is much smaller thanfor water and acetone. The experimental data was correlated with good results using two different activitycoefficient models, NRTL and UNIQUAC, with UNIQUAC giving better results, particularly for ciprofloxacin.The performance of COSMO-RS model to describe the studied systems was also evaluated.The dependence of these properties with temperature are shown. Theresults are interpreted in terms of solute-solvent interaction.

Characterization of seeds of selected wild species of rice (Oryza) stored under high temperature and humidity conditions.

Wild progenitors of rice (Oryza) are an invaluable resource for restoring genetic diversity and incorporating useful traits back into cultivars. Studies were conducted to characterize the biochemical changes, including SDS-PAGE banding pattern of storage proteins in seeds of six wild species (Oryza alta, O. grandiglumis, O. meridionalis, O. nivara, O. officinalis and O. rhizomatis) of rice stored under high temperature (45oC) and humidity (~100%) for 15 days, which facilitated accelerated deterioration. Under the treated conditions, seeds of different wild rice species showed decrease in per cent germination and concentrations of protein and starch, but increase in conductivity of leachate and content of sugar. The SDS-PAGE analysis of seed proteins showed that not only the total number of bands, but also their intensity in terms of thickness differed for each species under storage. The total number of bands ranged from 11 to 22, but none of the species showed all the bands. Similarity index for protein bands between the control and treated seeds was observed to be least in O. rhizomatis and O. alta, while the indices were 0.7 and 0.625 for O. officinalis and O. nivara, respectively. This study clearly showed that seed deterioration led to distinctive biochemical changes, including the presence or absence as well as altered levels of intensity of proteins. Hence, SDS-PAGE protein banding pattern can be used effectively to characterize deterioration of seeds of different wild species of rice.