Phase Behavior and Membrane Transport of Supersaturated Solutions in Complex Media

Supersaturating delivery systems, as a solubility enhancement strategy for poorly aqueous soluble drugs, are gaining increasing interest due to their ability to generate solution concentration of the drug in excess of its crystalline solubility, which can ultimately lead to an enhancement in oral bioavailability. Highly supersaturated solutions of hydrophobic compounds can undergo liquid-liquid phase separation (LLPS), wherein the concentration of the continuous solution phase is equal to the amorphous solubility and the dispersed phase is composed of excess amorphous drug that exists as nano-sized droplets. LLPS can occur both in vivo and in vitro . It has been suggested that, unlike crystallization, LLPS can be advantageous for oral absorption. Here, absorption across the intestinal membrane can take place from the continuous solution phase while the amorphous nanodroplets can serve as a drug reservoir, dissolving rapidly to replenish drug that has been lost due to absorption. This reservoir effect of the nanodroplets is experimentally demonstrated in this work. Current studies investigating LLPS have focused on the characterization of this phenomenon in simple media, in particular aqueous buffer solutions. However, gastrointestinal fluids are more complex. The variation in pH can impact the extent of supersaturation of ionizable drugs. Additionally, surfactants such as bile salts and phospholipids that are present in biorelevant dissolution media or in the intestinal fluids can also influence supersaturated systems. Amorphous solid dispersions (ASDs) are typically composed of an amorphous drug molecularly mixed with a polymer. However, formulators may also incorporate additives such as surfactants in the ASD to improve its wetting and dissolution. Addition of a surfactant can change the thermodynamics of the system. These surfactants can impact the solubility of the drug, the supersaturation that can be attained in the solution, as well as the crystallization kinetics in both the ASD and the solution generated by its dissolution. Although solubilization of crystalline drugs by pH and surfactants has been widely explored, there is little knowledge about their impact on either amorphous solubility or supersaturated solutions. This research aims to bridge the knowledge gap by studying the impact of pH on supersaturation and providing molecular understanding of the influence of surfactants on solubilization mechanisms of supersaturating systems. As surfactants in the biorelevant media can impact crystallization from supersaturated systems, the impact of biorelevant media composition on crystallization of drugs from supersaturated systems is also a focus of this study. LLPS can also occur due to dissolution of ASDs, leading to formation of nanodroplets. However, mechanisms leading to the formation of nanodroplets are still uncertain. In this research, the mechanism of nanodroplet generation was elucidated using isotope labelling. The understanding of phase behavior of supersaturated systems in complex media obtained through this research can aid in designing robust supersaturating formulations as well as predicting and modelling their in vivo performance

Studies on Primary Productivity of Khaire Reservoir, Raigad District, Maharashtra

Primary productivity study is important for the assessment of productivity of any aquatic systems. The present investigation is carried out to understand the status of primary productivity of Khaire reservoir of Raigad district. Analysis of primary productivity was done by using standard ‘Light and Dark bottle’ method of Boyd (1981) in every last week of the month for a period of two years (February 2014 – January 2016). In reservoir the values of GPP, NPP and CR were ranged from 0.38 to 2.81, 0.19 to 1.90 and 0.18 to 1.44 mg C L-1 hr-1 respectively. The results of the present study revealed that, the primary peak of productivity was observed during pre-monsoon season and the secondary peak was noticed during post-monsoon season. However, during the monsoon season low productivity values were recorded from the reservoir. From this it can be concluded that, Khaire reservoir is productive in nature

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Not AvailableBioassay was doneto find out the toxic effect of Phorate 10G on survival of Catla fingerlings. The moisture and total ash contents of the treated fingerlings increased, whereas crude protein and crude fat content decreased with the concentration and decreased with exposure period of Phorate 10GNot Availabl

Toxic effect of Phorate-10G pesticide on survival of fingerlings of Catla catla (Ham. 1822)

Bioassay was doneto find out the toxic effect of Phorate 10G on survival of Catla fingerlings. The moisture and total ash contents of the treated fingerlings increased, whereas crude protein and crude fat content decreased with the concentration and decreased with exposure period of Phorate 10

Seasonal variations of molluscs of Mirya sandy shore, Ratnagiri

1790-1795A total of 24 molluscan macro-faunal species comprising 21 bivalves and three gastropods, were recorded from the sandy shore Mirya, Ratnagiri. Among the bivalves the genus Donax and Sunetta were most abundantly recorded while the other species such as S. menstrualis, S. meroe, S. truncate, S. effosa and eight unidentified species of genus Sunetta showed patchy distribution. Other genus of bivalves such as Cardium falvum, Mactra corallina, Dosinia prostrata were also recorded which has not shown consistent occurrence throughout the study period. Gastropod Olivia olivia was the most abundant during all the months except in February while the species O. caricularia was recorded only in the month of February. Gastropod, Tibia curta was recorded only once in the month of December. Seasonal variations in molluscs were maximum during the post-monsoon and minimum during the monsoon season