No abstract

At the ICRISAT soil chemistry laboratory, a sulfuric acidselenium (Se) digestion method has been used for several years for determination of nitrogen (N) and phosphorus (P) in a single plant digest. The method is simple and was evaluated for determining N, P, potassium (K), Calcium (Ca), and magnesium (Mg) in plant samples using a single digest. Finely ground plant materials of pigeonpea (Cajanus cajan L.) and rice (Oryza sativa L.) plant samples were digested at 3708C. Digestion completed in about 2.5 h when the digests were clear and colorless. Results with plant samples having a wide range in elemental concentrations, showed that there was an excellent agreement in the values of various elements determined by the proposed digestion procedure and the routinely used Kjeldahl and triacid acid

Objective: The objective of the present study was to develop and characterize an optimal stable nanosponges of Gliclazide (GLZ) by using the emulsion solvent diffusion method and aimed to increase its bioavailability and release the drug in sustained and controlled manner. Methods: The GLZ nanosponge was prepared by emulsion solvent diffusion method using different drug-polymer ratios (1:1 to 1:5) Eudragit S100 is used as a polymer. Differential scanning calorimetry (DSC) and Fourier transform infrared spectroscopy (FTIR) estimated the compatibility of GLZ with polymer. All formulations evaluated for production yield, entrapment efficiency, in vitro drug release, scanning electron microscopy (SEM) and stability studies. Results: The DSC and FTIR Studies revealed that no interaction between drug and polymer. The Production yield of all batches in the range of 73.8±0.30 to 85.6±0.32. Batch F3 showed the highest production yield, the entrapment efficiency of batch F3 70.6±0.77. The average particle size ranges from 303±2.36 to 680±2.50 nm. By the end of 10th hour F3 formulation shown highest drug release was found to be 94.40±1.12%. The release kinetics of the optimized formulation shows zero-order drug release. The stability study indicates no significant change in the in vitro dissolution profile of optimized formulation. Conclusion: The results of various evaluation parameters, revealed that GLZ nanosponges would be possible alternative delivery systems to conventional formulation to improve its bioavailability, the emulsion solvent diffusion method is best method for preparation of nanosponges and release the drug in sustained and controlled manner.

Deficiency of sulfur (S) is becoming widespread in the rainfed systems of India, and there is increasing need for diagnosing the deficiency. Calcium chloride and Ca phosphate are commonly used for extracting available S in soils. Because of cost and the ease of availability locally, we prefer using Ca chloride as an extractant over Ca phosphate, for extracting available S. However, there is paucity of data on the comparative evaluation of the two extractants to extract available S, especially in soils having a wide range in natural pH (from acidic to alkaline range). It is recognized that soil pH plays a dominant role in the adsorption–desorption and extractability of sulfate‐S in soils. We compared the extraction of S by Ca chloride and Ca phosphate in 86 Indian soils having a wide range in pH (4.5 to 10.6). Sulfur in the extracts was determined by ICP‐AES. Considering all the 86 soil samples tested, there was an excellent agreement between the values of extractable S determined by using the two extractants (r = 0.96, p < 0.001). However, the correlation coefficient (r) between the values of extractable S by the two reagents, although highly significant, varied among the groups of soil samples according to the range in soil pH. The highest correlation coefficient (r = 0.99, p < 0.0001, n = 17) was found for soils with pH in the alkaline range (8.5–10.6), and the lowest correlation coefficient (r = 0.71, p < 0.0001, n = 58) was obtained with a set of soil samples with pH in the acidic range (4.5–6.5). For soil samples having pH in the near‐neutral range (6.7–7.3), an excellent agreement was observed (r = 0.93, p < 0.0001, n =11) between the extractable‐S values obtained by the two extractants. While Ca phosphate extracted higher amount of S compared to Ca chloride in soil samples with pH in the acidic range, the two extractants were equally effective for soil samples with pH in the neutral or alkaline range. Our results suggest that for most of the soils in the semiarid tropical regions, which have pH in the neutral to alkaline range, Ca chloride can replace Ca phosphate as an extractant for removing available S in such soils.

Boron (B) deficiency frequency is increasing in rainfed systems and hence the need to diagnose the deficiency. Colorimetric methods are still widely used in soil testing laboratories in India for measuring B. Little information is available on the comparative evaluation of the colorimetric and inductively coupled plasma (ICP) methods for determining extractable B in soils. We describe results on the comparative evaluation of these methods for measuring extractable B in 57 soil samples with pH ranging from 5.0 to 9.5. There was a significant correlation between B values determined by the two methods and the correlation coefficient was higher for soil samples with pH in the neutral to alkaline range. Interaction between soil samples and methods (ICP or colorimetric) was significant except for soil samples in the pH range of 8.0 to 9.5. Precision for B determination was greater with the ICP than with the colorimetric method.