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  • Author or Editor: W. Ali x
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A validated, sensitive, and highly selective stability-indicating high-performance thin-layer chromatographic (HPTLC) method has been adopted for the quantitative determination of pyridostigmine bromide in the presence of its alkaline-induced degradation product and in pharmaceutical formulations. 3-hydroxy-N-methyl pyridinium bromide (3-OH NMP) is the metabolite, impurity, and alkaline-induced degradation product of pyridostigmine bromide (PB). Pyridostigmine bromide and its alkaline-induced degradation product were separated on silica gel HPTLC F254 plates using methanol–ethyl acetate–triethyl amine–glacial acetic acid (9:1:0.5:0.05 by volume) as the developing system followed by scanning of the separated bands at 270 nm over a concentration range of 2–10 μg band−1 with mean percentage recoveries of 99.84% (SD 1.384). The proposed method was successfully applied to the analysis of pyridostigmine bromide both in bulk powder and in pharmaceutical formulation without interference from other dosage form additives. The results obtained by the proposed method were statistically compared with those obtained by the reported HPLC method with no significant difference regarding both accuracy and precision, indicating the ability of the proposed method to be reliable and suitable for routine analysis of a drug product.

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Higher plant population and nitrogen management is an adopted approach for improving crop productivity from limited land resources. Moreover, higher plant density and nitrogen regimes may increase the risk of stalk lodging, which is a consequence of complex interplant competition of individual organs. Here, we aimed to investigate the dynamic change in morphology, chemical compositions and lignin promoting enzymes of the second basal inter-nodes altering lodging risk controlled by planting density and nitrogen levels. A field trial was conducted at the Mengcheng research station (33°9′44″N, 116°32′56″E), Huaibei plain, Anhui province, China. A randomized complete block design was adopted, in which four plant densities, i.e., 180, 240, 300, and 360 × 104 ha−1 and four N levels, i.e., 0, 180, 240, and 300 kg ha−1 were studied. The two popular wheat varieties AnNong0711 and YanNong19 were cultivated. Results revealed that the culm lodging resistance (CLRI) index of the second basal internodes was positively and significantly correlated with light interception, lignin and cellulose content. The lignin and cellulose contents were significantly and positive correlated to light interception. The increased planting density and nitrogen levels declined the lignin and its related enzymes activities. The variety AnNong0711 showed more resistive response to lodging compared to YanNong19. Overall our study found that increased planting densities and nitrogen regimes resulted in poor physical strength and enzymatic activity which enhanced lodging risk in wheat varieties. The current study demonstrated that stem bending strength of the basal internode was significantly positive correlated to grains per spike. The thousand grain weight and grain yield had a positive and significant relationship with stem bending strength of the basal internode. The results suggested that the variety YanNong19 produces higher grain yield (9298 kg ha−1) at density 240 × 104 plants ha−1, and 180 kg ha−1 nitrogen, while AnNong0711 produced higher grain yield (10178.86 kg ha−1) at density 240 × 104 plants ha−1 and with 240 kg ha−1 nitrogen. Moreover, this combination of nitrogen and planting density enhanced the grain yield with better lodging resistance.

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