Abstract In the work the andrographolide (AG)-solid dispersions (SDs) were prepared by the spray-drying method, using polyethylene glycol 8000 (PEG8000), Poloxamer188, polyvinylpyrrolidone K30 (PVPK30), Soluplus® as carrier materials. The effect of different polymers as carrier materials on the properties of the AG-SDs were studied. The results showed obvious differences in intermolecular interaction, thermal stability, drug state, powder properties, dissolution behavior, and so on of AG-SDs prepared using different polymers as carrier materials. AG-PEG8000-SD was a partial-crystalline and partial-amorphous powder with smaller surface area and pore volume, but it was easy to wetting and did not swell in contact with dissolved medium. AG-Soluplus®-SD was completely amorphous powder with larger specific surface area and pore volume, but it swelled in contact with water. Therefore, the dissolution profile of AG in AG-PEG8000-SD was similar to that in AG-Soluplus®-SD. Soluplus® and PEG8000 were suitable polymers to design AG-SDs, considering both physicochemical properties and dissolution behaviors. The results of this reseach showed that when selecting carrier materials for SD, we should not only consider the state of drugs in SD and the powder properties of SD, but also consider whether there is swelling when the carrier materials are in contact with the dissolution medium.

In this paper, the interaction behavior of p-sulfonated calix[n]arene (SCnA) with tramadol hydrochloride was investigated by fluorescence spectra, ¹H NMR spectra, and theoretical calculations in aqueous solution. At the optimized conditions, the fluorescence intensity of tramadol hydrochloride showed positive correlation to the concentration of SCnA, which led to a validated, simple, and sensitive fluorescence quenching method for the determination of tramadol hydrochloride was established for the first time. Moreover, the interaction based on SCnA superstructure provided has promising potential for therapeutic monitoring and pharmacokinetics and clinical application

A new ionic liquid (IL) based micro-extraction method was developed for the spectrophotometry and spectrofluorometry determination of curcumin in curry products. ILs can effectively extract curcumin from aqueous solution which were used instead of large-scale organic solvents to reduce environmental pollution and production cost. Results show that the fluorescence of curcumin is considerably enhanced in 1-hexyl-3-methylimidazolium hexafluorophosphate ([Hmim][PF6]). Under optimized conditions, the absorbance of curcumin is proportional to the concentration of curcumin in the range of 18.4 ng/mL to 494 ng/mL, and the detection limit is 6.1 ng/mL. In addition, the fluorescence intensity of curcumin is proportional to the concentration of curcumin in the range of 0.050 ng/mL to 120.1 ng/mL, and the detection limit is 0.002 ng/mL. Therefore, an efficient spectrophotometry and spectrofluorometry method for the determination of curcumin was established, and the actual concentration in curry products was satisfactorily determined. The content of curcumin in curry sauce were 14.10±0.40 and 14.32±0.37 mg/g when using the spectrophotometry and spectrofluorometry, the content of curcumin in curry powder were 2.50±1.73 and 2.75±1.40 mg/g when using the spectrophotometry and spectrofluorometry.

Chitinase plays a positive role in the pathogenicity of Bacillus thuringiensis to insect pests. We used touchdown PCR to clone the chitinase (Schi) gene from Bacillus thuringiensis serovar sotto (Bt sotto) chromosomal DNA. Our DNA sequencing analysis revealed that the Bt sotto Schi gene consists of an open reading frame (ORF) of 2067 nucleotides with codes for the chitinase precursor. We also found that the putative promoter consensus sequences (the -35 and -10 regions) of the Bt soto Schi gene are identical to those of the chiA71 gene from Bt Pakistani, the chiA74 gene from Bt kenyae and the ichi gene from Bt israelensis. The Schi chitinase precursor is 688 amino acids long with an estimated molecular mass of 75.75 kDa and a theoretical isoelectric point of 5.74, and contains four domains, which are, in sequence, a signal peptide, an N-terminal catalytic domain, a fibronectin type III like domain and a C-terminal chitin-binding domain. Sequence comparison and the evolutionary relationship of the Bt sotto Schi chitinase to other chitinase and chitinase-like proteins are also discussed.