To establish a stable and reliable gas chromatography-tandem mass spectrometry method for the determination of N-nitrosodimethylamine (NDMA) in metformin hydrochloride sustained-release tablets, and to optimize extraction conditions by investigating the effects of isopropyl alcohol and thioglycerin on the stability of the tested solution.

Separation was achieved on AB-InoWax capillary column (30 m×0.25 mm×0.25 μm) with polyethylene glycol as the stationary phase. Electron ion(EI) source and multiple reaction monitoring (MRM) mode were used. Quantitative determination was performed by both external standard and internal standard.

The addition of thioglycerin could significantly improve the stability of the test solution. NDMA showed good linearity within the concentration range of 0.25-50 ng·mL^-1(r>0.999). The detection limit of the method was 0.1 ng·g^-1 and the quantification limit of the method was 0.2 ng·g^-1. The average recoveries (n=9) were 97.3% and 94.9% while using external standard and internal standard, respectively. Precision, repeatability and stability were good with RSD less than 8%. Ninety batches of metformin hydrochloride sustained release tablets were tested. NDMA content in all detected samples were all less than 30% of the acceptable limit set by the National Medical Products Administration and FDA.

This method shows satisfactory sensibility, specificity, accuracy, stability and durability, which is suitable for quantitative analysis of NDMA in metformin hydrochloride sustained-release tablets, providing technical support for the quality and safety of related products.

To establish a chromatogram-effect correlated quality evaluation system for the antibacterial activity of Flos Lonicerae extract by data analysis of components.

The best liquid chromatographic conditions were optimized by investigating the conditions of mobile phase, wavelength and flow rate, and the quantitative fingerprint of 50 batches of Flos Lonicerae extract was established. The best antibacterial concentration of the extract was obtained by microdilution method, and the antibacterial rates of 50 batches of samples were determined. Similarity analysis, cluster analysis, principal component analysis, grey correlation analysis and mathematical model establishment by support vector machine were used to analyze the quantitative fingerprints and antibacterial rates of 50 batches of samples.

Eighteen common peaks were selected from the 50 quantitative fingerprints of Flos Lonicerae extract, and the similarities were between 0.608-1. Six chemical components were identified (peak 4: neochlorogenic acid, peak 8: chlorogenic acid, peak 9: cryptochlorogenic acid, peak 16: isochlorogenic acid B, peak 17: isochlorogenic acid A and peak 18: isochlorogenic acid C). The average antibacterial rates of 50 batches of extracts were between 3.93%-70.50%. The results of principal component analysis and cluster analysis were highly consistent, and the results of grey correlation analysis showed that all components were positively correlated with antibacterial effect. The relative deviations between the predicted data of the mathematical model and the experimental data were all below 2%.

The HPLC conditions of Flos Lonicerae extract are stable and reliable, and the quality evaluation system of antibacterial activity of Flos Lonicerae extract established can evaluate its quality based on antibacterial rate.

To establish a simple and practical microbiological counting method suitable for sheet drug packaging materials by comparing the results of four sampling methods.

The samples of artificial contamination of sheet drug packaging materials were prepared by standard strain adding method. The surface microorganisms were collected by wiping method prescribed by national drug packaging container (material) standard, as well as by self-designed washing method, direct inoculation method and contact dish method. The corresponding recovery rate was calculated. The results of 4 sampling methods were analyzed by one way analysis of variance (ANOVA).

From high to low, the recovery rate was as follows: contact dish method, direct inoculation method, wiping method and washing method. There were significant differences in the recovery rates of contact dish method, wiping method and washing method (P<0.05). The recovery rate of contact dish method was slightly higher than that of direct inoculation method, but there was no significant difference between them (P>0.05). There was no significant difference in the recoveries of medicinal film, aluminum foil and hard sheet among the four methods (P>0.05).

The contact dish method is simple, sensitive and accurate, and can be used for the examination of the microbial limit counting method of sheet drug packaging materials.

To establish an amino solid-phase extraction-HPLC method for the determination of three related substances in eldecalcitol soft capsules.

The eldecalcitol soft capsules were extracted by an amino solid-phase extraction method, followed by eluting with ethyl acetate: n-hexane and anhydrous ethanol. The residue was then dissolved with acetonitrile and water after vacuum evaporation. An ODS column (250 mm×4.6 mm, 5 μm) was used. Water-acetonitrile with gradient elution was employed. The flow rate was 1.0 mL·min^-1, the injection volume was 50 μL, and the detection wavelength was set at 265 nm.

Interference from blank excipients was eliminated with pretreatment. Baseline separation and good selectivity of eldecalcitol and other impurities was achieved. The stability of the test and reference solution was investigated at 4 ℃. The area change percentage of the impurities in the test solution were 98.6%-102.3% at 24 h. The area change percentage of the impurities in the reference solution were 101.2%, 96.9%, 98.5% and 96.2% at 24 h, respectively. The quantitation limits of eldecalcitol, trans impurity, pre-eldecalcitol and tachy impurity were 0.107 μg·mL^-1, 0.102 μg·mL^-1, 0.128 μg·mL^-1 and 0.063 μg·mL^-1, respectively. The detection limits were 0.054 μg·mL^-1, 0.051 μg·mL^-1, 0.064 μg·mL^-1, 0.031 μg·mL^-1, respectively. The linear ranges of 4 components were 0.1-6.3 μg·mL^-, 0.1-1.2 μg·mL^-, 0.1-5.6 μg·mL^-and 0.1-1.1 μg·mL^-1, respectively. The correlation coefficients（n=5） were 0.999 9, 1.000, 1.000 and 0.999 4, respectively. The average recoveries （n=6）of tachy impurity, pre-eldecalcitol and trans impurity were 106.6%, 88.6% and 102.8% with RSDs of 6.7%, 3.1% and 2.1%, respectively. In the three batches of samples, no impurities were detected except pre-eldecalcitol. The contents of pre-eldecalcitol were 5.0%, 5.0% and 5.1%, respectively.

The method is simple to operate, economical and practical with high safety, strong specificity, good repeatability and high accuracy. The method provides a reliable basis for the study of drug quality such as eldecalcitol soft capsules and drugs with similar oily substrate.

To establish an HPLC characteristic chromatogram for Hyssopus cuspidatu Boriss. and control quality and identity authentication for the herb.

The HPLC method was used, and the mobile phases were acetonitrile (A) and 0.1% aqueous phosphoric acid (B) in gradient elution(0-15 min, 10% A; 15-30 min, 10% A→15% A; 30-40 min, 15% A→18% A; 40-60 min, 18% A→23% A; 60-70 min, 23% A→55% A; 70-85 min, 55% A→60% A; 85-85.1 min, 60% A→10% A; 85.1-90 min, 10% A). The column temperature was 30 ℃, the flow rate was 1.0 mL·min^-1, the detection wavelength was 330 nm and the injection volume was 20 μL. Fifteen batches of Hyssopus cuspidatu Boriss. and its adulterants, notably Cynanchum officinale, were analyzed to construct characteristic chromatogram. The authenticity and quality of Hyssopus cuspidatu Boriss. were assessed through principal component analysis(PCA), cluster analysis, and similarity analysis.

Analysis of the characteristic chromatogram of ten Hyssopus cuspidatu Boriss. batches revealed fifteen distinct peaks, with six compounds identified as isodendrobioside, molluscoside, rosmarinic acid, salvianolic acid, geranylgeranyl, and trichothecenes. Cluster analysis segregated the Hyssopus cuspidatu Boriss. samples into three distinct groups, primarily influenced by geographical (latitude and longitude) and environmental (climate) factors. PCA results indicated that four principal components accounted for 92.914% of the variance. The similarities for the ten batches of Hyssopus cuspidatu Boriss. ranged from 0.896 to 0.997, with no significant difference observed between the wild and cultivated varieties in terms of overall HPLC profile and relative peak content. The overall profiles of the HPLC characteristic chromatogram and the contents of the main components of the Hyssopus cuspidatu Boriss. and the Nepeta bracteata Benth. were significantly different.

The HPLC characteristic chromatogram method developed in this study is reproducible, stable, and practical for the quality control and authentication of Hyssopus cuspidatu Boriss. Moreover, it offers a reliable analytical technique for the quality evaluation and authentication of this herb, providing substantial data support.

To optimize the content determination method of morphine sulfate suppositories, which had high toxicity of extraction solvent and poor specificity and generality of chromatographic conditions.

The optimization of the preparation method for the test solution was to prepare the test solution by ice bath freezing and n-heptane extraction, and to compare the content determination results of the test solution prepared by the United States Pharmacopeia method (extracted with trichloromethane). The optimization of chromatographic conditions for content determination was based on the comprehensive comparison of United States Pharmacopeia, British Pharmacopeia and YBH specification. Symmetry C₁₈ column (150 mm×4.6 mm, 5 μm) was finally used. The mobile phase was 0.01 mol·L^-1 potassium dihydrogen phosphate solution containing 0.202% sodium heptane sulfonate (containing 0.1% triethylamine, adjusted to pH 2.5 with phosphoric acid) -methanol (70∶30). The flow rate was 1.0 mL·min^-1. The column temperature was 30 ℃. The detection wavelength was 284 nm. The injection volume was 20 μL.

The content measured by ice bath freezing method was relatively low, while the content measured by n-heptane extraction and trichloromethane extraction was basically consistent, indicating that n-heptane could be used as extraction solvent instead of halogenated alkane. The linear range of morphine sulfate was 2.12-105.94 μg·mL^-1(r=0.999 9), and the LOQ was 10.60 ng. The RSD values of system precision, repeatability, intermediate precision and stability were all less than 2%. The average recoveries were 98.6%-99.6% and RSD was 0.21%-0.66%. After forced degradation, the main peak of the tested solution could be separated from the degraded impurities, with good specificity. By changing the flow rate, column temperature, pH value, mobile phase ratio and column brand, the main peak could be well separated from each impurity peak, with good robustness.

This study optimized the determination method for morphine sulfate suppositories. The preparation of the test solution used n-heptane instead of the highly toxic haloalkane, and meanwhile improved the chromatographic conditions, enhanced the environmental protection, specificity and applicability of the method. It can be used for the content determination of morphine sulfate suppositories.

To establish a liquid chromatography mass spectrometry (LC-MS) method for the detection of nepasaikosaponin K in Bupleurum marginatum var. stenophyllum, which could be used to quickly identify whether Bupleurum marginatum var. stenophyllum was substituted for Bupleurum or was mixed with Bupleurum. At the same time, nepasaikosaponin K was detected in 16 batches of Bupleurum marginatum var. stenophyllum and 157 batches of bupleurum decoction pieces.

Ultra-high performance liquid chromatography (UPLC) coupled with triple quadruple mass spectrometry (QqQ MS) was used to detect nepasaikosaponin K in Bupleurum and Bupleurum marginatum var. stenophyllum. Determination was carried out with the application of a Phenomenex Kinetex C₁₈ (2.1 mm×100 mm, 1.7 μm) column at temperature of 25 ℃. The mobile phase was composed of acetonitrile(A) and water(B) with gradient elution(0-5 min 15% A→25% A; 5-0 min, 25% A→30% A; 30-35 min, 30% A→90% A; 35-36 min, 90% A→15% A; 36-40 min, 15% A) at a flow rate of 0.3 mL·min^-1. The electrospray ionization(ESI^-) source was performed in multiple reaction monitoring (MRM) mode of the transitions of m/z 943.5→797.3, m/z 943.5→635.3, and m/z 943.5→781.3.

The contents of nepasaikosaponin K detected in 16 batches of Bupleurum marginatum var. stenophyllum were much higher than minimum requirements. Nepasaikosaponin K was detected in 8 out of 157 batches of Bupleurum.

The established method is verified by methodology to be specific, so as to develop a supplementary test method for the components of Bupleurum and Bupleurum marginatum var. stenophyllum. to improve the quality control standard and authentic identification investigation, and to effectively control the quality of Bupleurum decoction pieces and guarantee its clinical efficacy.

The early warning of new psychoactive substance iso-propoxate (homologue of etomidate) was carried out through sewage drug monitoring technology, and quantitative research was conducted to provide technical support for management and law enforcement.

The abnormal results were obtained by quantitative analysis of multiple reaction monitoring (MRM) mode using online solid phase extraction-ultra high performance liquid chromatography tandem mass spectrometry (SPE-UPLC-MS/MS), and the basic information of abnormal substance was determined by precursor ion scanning mode. The qualitative determination was carried out using parallel reaction monitoring (PRM) mode by ultra high performance liquid chromatography quadrupole-orbitrap high resolution mass spectrometry (UPLC-Q exactive HRMS) after the directional synthesis of the compound. Quantitative study was then conducted by commercial reference products. The correlation analysis was carried out by SPSS 27.

The abnormal substance was determined to be iso-propoxate. The optimized MRM parameters could be distinguished from its isomers by specific ion abundance ratio. The correlation analysis of quantitative results showed that it was similar to etomidate and ketamine abuse areas.

In the process of sewage drug monitoring, it is necessary to pay attention to the proportional relationship between prototype and metabolite. It is important to summarize the characteristic fragments and characteristic neutral loss information of specific types of compounds, carry out screening non-targeted detection for key samples in key areas in the monitoring process, and analyze potential substances using high-resolution mass spectrometry and other methods, so as to fully leveraging the early warning role of sewage drug monitoring.

To design and screen specific primers for efficient amplification and identification of Arnebiae Radix from market based on the concept of nested PCR.

Nested primers was designed using the software of Primer Premier 5 based on the ITS sequence of Arnebia euchroma and the ITS2 sequence of non-pharmacopoeial Arnebiae Radix. The amplification efficiency of genomic DNA by ITS2 universal primers PCR and nested PCR was compared. The genomic DNA of Arnebiae Radix was amplified directly by nested primers and was detected by agarose gel electrophoresis. The specific primers designed for Arnebiae Radix based on the fragment length and variation sites’ coverage of the amplified product was evaluated.

A total of 11 primers were selected for synthesis after the primers were designed by Primer Premier 5 software. The amplification efficiency of nested PCR was superior to ITS2 universal primers PCR in genomic DNA of Arnebiae Radix. The results of nested primers directly amplified genomic DNA of Arnebiae Radix by agarose gel electrophoresis were better than those of ITS2 primers，and showed a single band. Four pairs of primers，AE-9S/AE-2A，AE-4S/AE-10A，AE-12S/10A，AE-29S/AE-29A，were determined to be suitable for the identification of Arnebiae Radix.

On the basis of DNA barcode identification and nested PCR technology，4 pairs of specific primers are identified which can be used to effectively distinguish Arnebia euchroma from the mainstreamed non-pharmacopoeial Arnebiae Radix in the medicinal materials market，providing reference for the subsequent research and development of identification methods for Arnebiae Radix and other traditional Chinese medicines.