OBJECTIVE To establish an ultra performance liquid chromatography-tandem mass spectrometry(UPLC-MS/MS)method for determination of dexmedetomidine(DEX)in plasma of beagle dogs and evaluate the pharmacokinetics and sedation after nasal,buccal and sublingual mucosal admin-istration.METHODS A UPLC-MS/MS method was established and validated for dertermination of DEX in plasma of beagle dogs.DEX was administered to the nasal cavity,buccal and sublingual mucous membranes of beagle dogs,respectively.Blood samples were collected at different time points.The plasma concentration of DEX was measured by the established UPLC-MS/MS method.Pharmacokinetic parameters were fitted by Phoenix software and the sedative effect at different mucous membrane sites was evaluated in conjunction with behavioral and Ramsay scores.RESULTS The linearity of DEX was fine within the range of 0.05-100 μg·L-1(r>0.999),which was validated methodologically to meet the requirements of quantitative detection.The plasma concentration of the drug peaked the fastest with nasal administration.Tmax was 0.25 h,Cmax(4.43±1.19)μg·L-1,and the AUC0-6h was(8.92±2.07)μg·h·L-1,compared with 0.92 and 1 h,(2.87±0.69),(2.70±0.41)μg·L-1,and(7.99±1.77),(7.01±2.09)μg·h·L-1 with buccal and sublingual administration.Nasal administration had the fastest onset at 7 min,with a Ramsay score of 4,and sedation lasted for 36 min,compared with 33 and 35 min,and 38 and 37 min for buccal and sublingual administration.CONCLUSION The proposed method is sensitive,reliable and applicable to quantitative analysis of DEX in plasma of beagle dogs.Administration of DEX to the nasal cavity mucosa has a faster onset and a better sedative effect than to the buccal and sublingual mucosa.

Objective To explore the protective effect of 7,8-dihydroxyflavone(7,8-DHF)on the retina of diabetic rats and its mechanism.Methods A total of 18 SPF-grade male Sprague-Dawley(SD)rats were selected and randomly divided into three groups:the normal group,the model group,and the experimental group,with six rats in each group.Rats in the normal group were fed with a normal diet,while those in the remaining two groups were fed with a high-fat emulsion through oral gavage continuously for 2 weeks to establish a diabetes model.Rats in the experimental group were provided with 7,8-DHF(5 mg?kg-1)by continuous intraperitoneal injection,while those in the normal and model groups were provided with an equal volume of normal saline.The rats in all groups received intervention once a day for 2 weeks.The changes in the body mass and fasting blood glucose(FBG)were observed before and after modeling.Besides,the changes in the retina of rats in each group were observed by fundus fluorescence angiography(FFA)after 2 weeks.Moreo-ver,the changes and apoptosis of retinal neuronal cells were detected by hematoxylin and eosin(HE)staining,CD31 im-munofluorescence,and terminal deoxynucleotidyl transferase dUTP nick end labeling(TUNEL)assays.Results After 2 weeks of continuous intervention,compared with the normal group,the body mass of rats in the model and experimental groups decreased(both P＜0.05),and the FBG increased significantly(both P＜0.05);compared with the model group,the experimental group showed an increase in the body mass(P＜0.05)and a decrease in the FBG(P＜0.05).The fundus photography and FFA of rats in the three groups did not reveal any fundus features of diabetic retinopathy.The HE staining results showed that the retina of rats in the normal and experimental groups was structurally intact,with neatly arranged cells and uniform thickness;the retinal structure of rats in the model group remained clear.However,the thickness of the inner layers of the retina of rats in the model group was thinner compared with the normal and experimental groups,exhibi-ting significant differences(both P＜0.05).The CD31 immunofluorescence assay results indicated that the CD31 immuno-fluorescence intensity values of rats in the three groups were roughly comparable,without significant differences(all P＞0.05).The TUNEL assay results suggested that the apoptosis of retinal neurons increased in rats in the model group com-pared with the normal group,exhibiting significant differences(P＜0.001);compared with the model group,the apoptosis of retinal neurons of rats in the experimental group decreased significantly,displaying significant differences(P＜0.001).Conclusion The apoptosis of retinal neurons in diabetic rats may precede vascular endothelial cell injury.7,8-DHF can improve the body mass,decrease the blood glucose level,and protect the retinal neurons in diabetic rats.

Hot melt extrusion(HME)technology employs thermodynamic and kinetic principles to mix pharmaceutical polymers with crystalline drugs at high temperatures and extrude them,embedding drug molecules within the polymer matrix to form solid dispersions.Due to its solvent-free nature,capability for one-step processing,and support for continuous operation,HME has garnered significant attention in the pharmaceutical industry in recent years.This article introduced the basic principles and development history of HME technology and its marketed drugs.It reviewed the research progress of HME technology in improving drug solubility,masking taste,controlled release,targeted release,oral dispersible films,implant formulations,semi-solid formulations,and 3D printed formulations.Additionally,the article summarized the advantages and limitations of HME technology and provided an outlook on its future development.

In recent years, potato scab caused by Streptomyces scabies is aggravating year by year, becoming an industrial problem urgently to be resolved. Screening antagonistic bacteria with good inhibitory effect and wide adaptability is the main measure to realize effective prevention and control of the disease. This study screened three strains of antagonistic bacteria DXT2-4, T2-1 and 21-14 with good inhibitory effect on S. scabies by using plate standoff test, and identified them as Bacillus altitudinis, Bacillus safensis and Bacillus pumilus, respectively, based on morphological characteristics, physiological and biochemical properties, and 16S rRNA gene sequences. DXT2-4, T2-1 and 21-14 showed the pot control efficacy of 68.83%, 48.57%, and 57.14%, respectively. The field control efficacy of the three strains was 59.48%, 34.58% and 51.75% in Hulun Buir, Inner Mongolia Autonomous Region and 55.14%, 36.05%, and 49.05% in Huizhou, Guangdong. The three strains could grow normally in the media with pH 1.0-13.0 and with 1%-11% NaCl, and they had inhibitory effects on Rhizoctonia solani, Verticillium dahliae, Alternaria solani, and Fusarium oxysporum. The indole-3-acetic acid yields of DXT2-4, T2-1, and 21-14 were 2.23, 1.11, and 1.67 mg/L, respectively. DXT2-4 and 21-14 demonstrated strong abilities to solubilize phosphorus. The optimal carbon source, nitrogen source, and inorganic salt for fermentation of strain DXT2-4 were 2% molasses+2% corn starch, 2% soybean meal, and 0.3% MgSO₄·7H₂O, respectively. These findings suggest the three strains of bacteria can efficiently inhibit the growth of S. scabies and have strong environmental adaptability. Particularly, DXT2-4 has the best effects of inhibiting the disease and promoting plant growth, showing a high development value and broad application prospects, this is of great significance for promoting sustainable potato production and ensuring the environmentally sound utilization of resources.
Streptomyces/metabolism* ; Fermentation ; Plant Diseases/prevention & control* ; Solanum tuberosum/growth & development* ; Bacillus/growth & development* ; Antibiosis

Objective To explore the protective effect of 7,8-dihydroxyflavone(7,8-DHF)on the retina of diabetic rats and its mechanism.Methods A total of 18 SPF-grade male Sprague-Dawley(SD)rats were selected and randomly divided into three groups:the normal group,the model group,and the experimental group,with six rats in each group.Rats in the normal group were fed with a normal diet,while those in the remaining two groups were fed with a high-fat emulsion through oral gavage continuously for 2 weeks to establish a diabetes model.Rats in the experimental group were provided with 7,8-DHF(5 mg?kg-1)by continuous intraperitoneal injection,while those in the normal and model groups were provided with an equal volume of normal saline.The rats in all groups received intervention once a day for 2 weeks.The changes in the body mass and fasting blood glucose(FBG)were observed before and after modeling.Besides,the changes in the retina of rats in each group were observed by fundus fluorescence angiography(FFA)after 2 weeks.Moreo-ver,the changes and apoptosis of retinal neuronal cells were detected by hematoxylin and eosin(HE)staining,CD31 im-munofluorescence,and terminal deoxynucleotidyl transferase dUTP nick end labeling(TUNEL)assays.Results After 2 weeks of continuous intervention,compared with the normal group,the body mass of rats in the model and experimental groups decreased(both P＜0.05),and the FBG increased significantly(both P＜0.05);compared with the model group,the experimental group showed an increase in the body mass(P＜0.05)and a decrease in the FBG(P＜0.05).The fundus photography and FFA of rats in the three groups did not reveal any fundus features of diabetic retinopathy.The HE staining results showed that the retina of rats in the normal and experimental groups was structurally intact,with neatly arranged cells and uniform thickness;the retinal structure of rats in the model group remained clear.However,the thickness of the inner layers of the retina of rats in the model group was thinner compared with the normal and experimental groups,exhibi-ting significant differences(both P＜0.05).The CD31 immunofluorescence assay results indicated that the CD31 immuno-fluorescence intensity values of rats in the three groups were roughly comparable,without significant differences(all P＞0.05).The TUNEL assay results suggested that the apoptosis of retinal neurons increased in rats in the model group com-pared with the normal group,exhibiting significant differences(P＜0.001);compared with the model group,the apoptosis of retinal neurons of rats in the experimental group decreased significantly,displaying significant differences(P＜0.001).Conclusion The apoptosis of retinal neurons in diabetic rats may precede vascular endothelial cell injury.7,8-DHF can improve the body mass,decrease the blood glucose level,and protect the retinal neurons in diabetic rats.

OBJECTIVE To establish an ultra performance liquid chromatography-tandem mass spectrometry(UPLC-MS/MS)method for determination of dexmedetomidine(DEX)in plasma of beagle dogs and evaluate the pharmacokinetics and sedation after nasal,buccal and sublingual mucosal admin-istration.METHODS A UPLC-MS/MS method was established and validated for dertermination of DEX in plasma of beagle dogs.DEX was administered to the nasal cavity,buccal and sublingual mucous membranes of beagle dogs,respectively.Blood samples were collected at different time points.The plasma concentration of DEX was measured by the established UPLC-MS/MS method.Pharmacokinetic parameters were fitted by Phoenix software and the sedative effect at different mucous membrane sites was evaluated in conjunction with behavioral and Ramsay scores.RESULTS The linearity of DEX was fine within the range of 0.05-100 μg·L-1(r>0.999),which was validated methodologically to meet the requirements of quantitative detection.The plasma concentration of the drug peaked the fastest with nasal administration.Tmax was 0.25 h,Cmax(4.43±1.19)μg·L-1,and the AUC0-6h was(8.92±2.07)μg·h·L-1,compared with 0.92 and 1 h,(2.87±0.69),(2.70±0.41)μg·L-1,and(7.99±1.77),(7.01±2.09)μg·h·L-1 with buccal and sublingual administration.Nasal administration had the fastest onset at 7 min,with a Ramsay score of 4,and sedation lasted for 36 min,compared with 33 and 35 min,and 38 and 37 min for buccal and sublingual administration.CONCLUSION The proposed method is sensitive,reliable and applicable to quantitative analysis of DEX in plasma of beagle dogs.Administration of DEX to the nasal cavity mucosa has a faster onset and a better sedative effect than to the buccal and sublingual mucosa.

Hot melt extrusion(HME)technology employs thermodynamic and kinetic principles to mix pharmaceutical polymers with crystalline drugs at high temperatures and extrude them,embedding drug molecules within the polymer matrix to form solid dispersions.Due to its solvent-free nature,capability for one-step processing,and support for continuous operation,HME has garnered significant attention in the pharmaceutical industry in recent years.This article introduced the basic principles and development history of HME technology and its marketed drugs.It reviewed the research progress of HME technology in improving drug solubility,masking taste,controlled release,targeted release,oral dispersible films,implant formulations,semi-solid formulations,and 3D printed formulations.Additionally,the article summarized the advantages and limitations of HME technology and provided an outlook on its future development.

ObjectiveBased on the traditional quality evaluation methods summarized in previous dynasties， this paper systematically contrasted cultivated Astragali Radix（CA） and wild-simulated Astragali Radix（WA） from the aspects of character， microstructure and chemical composition by modern technological means. MethodThe collected CA and WA were compared in characters and microscopic characteristics in cross section， and comparative analysis were performed on the contents of cellulose， extracts， carbohydrate， total flavonoids， total saponins， etc. Then ultra-high performance liquid chromatography-quadrupole-time-of-flight mass spectrometer（UPLC-Q-TOF-MS） and desorption electrospray ionization mass spectrometry imaging（DESI-MSI） were used to comparatively analyze the secondary metabolites and their spatial distributions in the xylem and phloem of CA and WA. ResultIn terms of characters， the characters and sectional features of WA was consistent with the characteristics of high-quality Astragali Radix， while the CA was quite different from the traditional high-quality Astragali Radix. In terms of microscopy， the phellem layer of CA was thin， and the section fissures were mostly distributed through the cambium in a long strip shape without obvious growth ring characteristics. The cork layer of WA was thick， and the cracks in the section were distributed in the center of the xylem and the outer edge of the phloem in an irregular cavity shape. The cambium was tight without cracks， and had obvious characteristics of a growth ring. In terms of chemical composition， the contents of water-soluble extract， 80% ethanol extract and sucrose of CA was significantly higher than those of WA， while the contents of total saponins， lignin and hemicellulose were significantly lower than those of WA. And the contents of 100% ethanol extract， total polysaccharides and total flavonoids in both of them were generally similar， but slightly higher in WA. The contents of 2 kinds of monoacyl-substituted flavonoid glycosides in the xylem of WA was significantly higher than those of CA， while the contents of 2 kinds of flavonoid aglycones and one flavonoid glycoside were on the contrary. The contents of 7 saponins in phloem of WA were significantly higher than those of CA. ConclusionThere are significant differences between CA and WA in characters， microstructure and chemical components， in which CA has a fast growth rate and a short planting period， and the primary metabolites such as water-soluble extracts and sucrose are more enriched， which is the reason for its firm texture and sweetness being significantly higher than those of WA. However， the contents of lignin， hemicellulose and some secondary metabolites in WA are significantly higher than those in the CA， which are close to the traditional description of characters and quality. Based on the results of this study， it is suggested to strengthen the production of WA， improve the supply capacity of WA， and gradually upgrade the current standard. It is recommended to increase the contents of monoacyl-substituted flavonoid glycosides， total saponins and other indicators that can characterize different production methods， so as to guide the high-quality production of Astragali Radix.