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Background: Xanthan gum (XG) is a natural polymer with numerous uses. But its poor tableting and release charact1eristics reduce its usage as a tablet matrix former. Hence, the aim of the study is to improve the quality of XG by blending it with a successful semisynthetic polymer, hypromellose (HPMC). Methods: Extended release (ER) tablets were made using wet granulation technique using XG and HPMC blend. The blend was optimised using Central composite design. Prepared tablets were evaluated for in vitro tableting characteristics and drug release. In vivo absorption studies are carried out in New Zealand white rabbits. Results: Under optimal conditions, the ideal combination of factors was observed in the range of X1: 2.75-4.25 %w/w and X2: 10-20% w/w. At these finest concentrations, the predictable responses, the drug release at 4th hr was 36.31-40.34%, 20th hr was 82.21-91.43% and the hardness of the tablet was 6.6-8.5 kg/Cm2. The drug release of the optimized batch (RANERT 14) showed 90.9% similarity with the standard commercial ER tablets. Further, in vivo pharmacokinetic testing of the same batch showed, bioavailability (88.0 ±2.5%), mean residence time (16.1± 2.85 h) and biological half-life (11.47 ±0.42 h) against pure drug (BA: 65.0 4%; MRT: 5.1± 2.85 h; t1/2: 2.6151 ± 0.54 h). Conclusion: Comparable drug release profiles with the commercial tablets and enhanced pharmacokinetic profile made this combination as successful in achieving extended-release for a period of 24 hr by overcoming the drawbacks associated with XG. [ABSTRACT FROM AUTHOR]

Zeaxanthin is an important natural pigment which has found commercial application in food and nutritional supplements. Its potential widespread use requires an easy and effective extraction methodology for obtaining higher yields. Extraction from Chlorella sp. under optimized conditions demonstrated a marked reduction in extraction time (13.48 min) compared with a control experiment (30 min). The extraction conditions such as solvent/cell dry weight (CDW) ratio, power, pulse, time and their combinations were optimized using response surface methodology (RSM). Almost all the variables were shown significantly ( p -value <0.05) affect the carotenoid yield. Significant interaction ( p -value <0.05) was observed with a substantial effect on zeaxanthin yield for solvent/CDW ratio and power, as well as power and time, whereas the β-carotene control exhibited significant interaction between solvent/CDW ratio and pulse, as well as between pulse and time. The R 2 -value approached unity in both models, demonstrating their accuracy. Data obtained from these interactions were used to construct 3D response plots. Solvent/CDW ratio of 67.38 µl mg −1 , power 27.82% (total power 500 W), pulse length of 19.7 s and time 13.48 min were found to be the optimized conditions for zeaxanthin (11.2 mg g −1 ) and β-carotene (4.98 mg g −1 ) extraction. [ABSTRACT FROM AUTHOR]

• NH 4 +/NO 3 − and K+ for hydroponically-grown radish were researched. • CCD and RSM methods were applied to model. • Influence of NH 4 +/NO 3 − and K+ on plants were discussed based on models. • Better nutrient solution for specific hydroponically-grown radish was found. Central composite design and response surface methodology were applied to model bulb fresh weight, bulb dry weight, and whole-plant dry weight, based on ammonium/nitrate and potassium in nutrient solution for hydroponically grown radish between November and December in New Zealand. Three high-precision second-order models were developed. The R2 values were more than 0.90, Pre R2 values were reasonable, and Adeq Precision values were more than 10. The contributions of the two factors to the response variables were studied, and optimal nutrition was discussed using these models. Both factors affected the three response variables significantly and nonlinearly (all p values < 0.05). Ammonium/nitrate played a more important role than potassium in bulb fresh weight (p = 0.00 versus p = 0.01). The negative or positive influence of one factor on bulb fresh weight and whole-plant dry weight depended on the concentration of ammonium/nitrate and potassium. Nutrient solutions with ammonium/nitrate 4:11 (0.36) and potassium 5.6 mM, and with ammonium/nitrate 5:10 (0.50) and potassium 6.0 mM were both better than those of Hoagland and Anrnon for hydroponically Summer-grown radish in New Zealand. [ABSTRACT FROM AUTHOR]