[Determination of misoprostol in workplace air by high performance liquid chromatography].

Objective: To establish a high performance liquid chromatography method for the determination of misoprostol in workplace air. Methods: From February to August 2021, the misoprostol in the workplace air was collected by glass fiber filter membrane, and theeluent was separated by C18 liquid chromatography column, determined by UV detector, and quantified by external standard method. Results: The quantitative lower limit of misoprostol determination method was 0.05 µg/ml, and the lowest quantitative concentration was 1.4 µg/m(3) (calculated by collecting 75 L air sample). The concentration of misoprostol has a good linear relationship between 0.05 to 10.00 µg/ml. The relative coefficient was 0.9998. The regression equation of the standard working curve was y=495759x-45257. The range of average recovery rates were from 95.5% to 102.8%. The intra-assay precision of the method was 1.2%-4.6%, and the inter-assay precision was 2.0%-5.9%. The samples could be stored stably for 7 days at 4 ℃. Conclusion: The high performance liquid chromatography method for the determination of misoprostol has high sensitivity, good specificity and simple procedure of sample pretreatment. It is suitable for the detection of misoprostol in the workplace air.

Optimization and verification of size exclusion chromatography-high performance liquid chromatography for determination of recombinant human growth hormone-Fc immunofusion protein polymer / 中国生物制品学杂志

@#Objective To optimize and verify the size exclusion chromatography-high performance liquid chromatography(SEC-HPLC) method for the determination of recombinant human growth hormone(rhGH)-Fc immunofusion protein polymer.Methods The multimer content of rhGH-Fc immunofusion protein was detected by SEC-HPLC.The detection conditions(salt concentration,mobile phase pH,flow rate,column temperature and column model) were optimized to observe the separation effect of the target proteins and polymers.The system suitability,specificity,linearity and range,precision,accuracy and limit of quantification of the method were verified.Results The optimized method was to use TSK-gel G2000SW_(x1)column(5 μm,7.8 mm × 300 mm),mobile phase of 50 mmol/L phosphate buffer(pH 6.80),detection wavelength of280 nm,injection volume of 100 μL,flow rate of 0.6 mL/min and column temperature of 45 ℃.The resolution of rhGHFc immunofusion protein and polymer,the theoretical plate number and the tailing factor all met the requirements;the peak time of rhGH-Fc immunofusion protein was the same as that of the control,while the peak time of GH national standard was different from that of the control,and the protein buffer showed no peak;the concentration of rhGH-Fc immunofusion protein was in the range of 0.307～1.842 mg/mL with good linear correlation between the peak area integral value and the injection volume(R~2=0.999 4);the RSD of peak area and purity in repeatability verification were 0.7% and 0.1%,respectively;the RSD of intermediate precision verification was 0.8%;the average recovery rate of accuracy verification was 99.1% with the RSD of 1.9%;the limit of quantification was 6 μg/mL.Conclusion The optimized SEC-HPLC method was used to detect the content of polymer in rhGH-Fc immunofusion protein with improved accuracy,and the column efficiency and separation were in accordance with the relevant requirements of Chinese Pharmacopoeia(Volume Ⅳ,2020edition),which could be used for the detection of polymer content in samples.

Determination of misoprostol in workplace air by high performance liquid chromatography / 中华劳动卫生职业病杂志

Objective: To establish a high performance liquid chromatography method for the determination of misoprostol in workplace air. Methods: From February to August 2021, the misoprostol in the workplace air was collected by glass fiber filter membrane, and theeluent was separated by C18 liquid chromatography column, determined by UV detector, and quantified by external standard method. Results: The quantitative lower limit of misoprostol determination method was 0.05 μg/ml, and the lowest quantitative concentration was 1.4 μg/m(3) (calculated by collecting 75 L air sample). The concentration of misoprostol has a good linear relationship between 0.05 to 10.00 μg/ml. The relative coefficient was 0.9998. The regression equation of the standard working curve was y=495759x-45257. The range of average recovery rates were from 95.5% to 102.8%. The intra-assay precision of the method was 1.2%-4.6%, and the inter-assay precision was 2.0%-5.9%. The samples could be stored stably for 7 days at 4 ℃. Conclusion: The high performance liquid chromatography method for the determination of misoprostol has high sensitivity, good specificity and simple procedure of sample pretreatment. It is suitable for the detection of misoprostol in the workplace air.

[Study on determination of 2-thioxothiazolidine-4-carboxylic Acid in urine by high performance liquid chromatography].

Objective: To establish a high performance liquid chromatography method for the determination of 2-thioxothiazolidine-4-carboxylic acid (TTCA) in urine. Methods: After acidification with hydrochloric acid, TTCA in urine was first extracted by ethyl acetate with excessive sodium chloride, then gradient separated by a symmetry C18 column and then detected by a diode array detector. The quantification was based on a working curve of external standard method. Results: The linear relationship of TTCA in urine was good in the range of 0.03-10.00 mg/L, and the correlation coefficient was 0.9999. The detection limit and minimum quantitative concentration of TTCA in urine were 0.008 mg/L and 0.027 mg/L. The intra-assay precision of the method was 0.9%-1.4%, the inter-assay precision was 1.3%-3.5%, and the average recovery was 85.0%-92.7% while the concentrations of TTCA in urine was 0.8, 2.0 and 8.0 mg/L, respectively (n=6) . Conclusion: The gradient elution high performance liquid chromatography method has simple operation and high sensitivity, and it is suitable for the determination of TTCA on a low level in urine for occupational workers exposure to carbon disulfide.

Study on determination of 2-thioxothiazolidine-4-carboxylic Acid in urine by high performance liquid chromatography / 中华劳动卫生职业病杂志

Objective: To establish a high performance liquid chromatography method for the determination of 2-thioxothiazolidine-4-carboxylic acid (TTCA) in urine. Methods: After acidification with hydrochloric acid, TTCA in urine was first extracted by ethyl acetate with excessive sodium chloride, then gradient separated by a symmetry C18 column and then detected by a diode array detector. The quantification was based on a working curve of external standard method. Results: The linear relationship of TTCA in urine was good in the range of 0.03-10.00 mg/L, and the correlation coefficient was 0.9999. The detection limit and minimum quantitative concentration of TTCA in urine were 0.008 mg/L and 0.027 mg/L. The intra-assay precision of the method was 0.9%-1.4%, the inter-assay precision was 1.3%-3.5%, and the average recovery was 85.0%-92.7% while the concentrations of TTCA in urine was 0.8, 2.0 and 8.0 mg/L, respectively (n=6) . Conclusion: The gradient elution high performance liquid chromatography method has simple operation and high sensitivity, and it is suitable for the determination of TTCA on a low level in urine for occupational workers exposure to carbon disulfide.

[Distribution and metabolism of toxicants in rats with phenol burn].

Objective: To study the distribution and metabolism of toxicants in rats after phenol burn. Methods: In February 2019, SPF-grade healthy SD male rats were transdermally exposed to 6 mg/kg phenol to create a 5% body surface burn model of rats. High performance liquid chromatography was used to determine phenol content in rat plasma and kidney tissues after 0.25, 0.75, 2, 4, 8, 16, and 32 h, respectively. The kinetic parameters of phenol were calculated by DAS 2.0 software, and the kidney targeting of phenol was evaluated. Results: The area under the blood concentration-time curve at 0-8 h (AUC(0-8)) of the rat after phenol burn was (28.741±6.485) µg/ml·h, and the area under the blood concentration-time curve from 0 to infinite time (AUC(0-∞)) was (30.354±6.424) µg/ml·h, half-life (t(1/2)) was (2.111±0.632) h, peak concentration (C(max)) was (16.287±4.870) µg/ml, mean residence time (MRT) was (1.854±0.148) h. The target efficiency (DTE) of rat kidney was 2.91. Conclusion: Phenol burn rats have fast percutaneous absorption, rapid elimination of phenol, and have high clearance rate, short MRT, and weak substance accumulation. Phenol has relatively obvious selectivity to the kidneys.

Stability Determination of an Extemporaneously Compounded Ambrisentan Suspension by High Performance Liquid Chromatography Analysis.

OBJECTIVE: Ambrisentan, an endothelin receptor antagonist FDA-approved for the treatment of pulmonary arterial hypertension in adult patients, lacks an acceptable pediatric dosage form. The objective of this investigation was to determine the stability of an extemporaneously compounded ambrisentan suspension. METHODS: Ambrisentan suspension was compounded to a concentration of 1 mg/mL using commercially available suspending agents. The suspension was then evenly split into 2 plastic amber prescription bottles. One bottle was stored at room temperature and under continuous fluorescent light while the other bottle was stored under refrigeration and protection from light. A fast and selective reversed-phase high-performance liquid chromatography (HPLC) method was developed and validated for the analysis of ambrisentan. HPLC analysis was performed on samples withdrawn from the stock bottles at predetermined time intervals, up to 90 days. RESULTS: The developed HPLC method enabled the elution and detection of ambrisentan peak at 4.4 minutes. HPLC analysis revealed that all samples from both storage conditions retained >90% potency throughout the study timeframe. There were no signs of any ambrisentan breakdown products on HPLC analysis. Color and odor of the final product was also consistent throughout the 90-day storage period. CONCLUSION: Ambrisentan suspension, compounded to 1 mg/mL, is stable at room temperature or under refrigeration for up to 90 days.

Identification of the active ingredients from Guangtongxiao decoction in rat bile based on ultra-performance liquid chromatography/Synapt G2 quadrupole time-of-flight tandem mass spectrometry.

OBJECTIVE: To identify the active ingredients and metabolites in rat bile after Guangtongxiao decoction (GTX) had been administered via the rectal route. METHODS: Drug-containing bile samples were collected via a catheter in the bile duct and could be used 5 h after rectal administration. The main active components and their metabolites in rat bile following rectal administration of GTX were identified and analyzed using ultra-high-performance liquid chromatography-quadrupole time-of-flight mass spectrometry. RESULTS: Positive and negative modes were applied to analyze and identify the chemical ingredients in the bioactive fractions of GTX. Eight peaks were identified by comparison with the standard compounds: berberine hydrochloride, dehydrocorydaline, tetrahydropalmatine, corydaline, magnoflorine, magnolol, obacunone and albiflorin. Furthermore, 60 metabolites were detected in rat bile based on mass-fragmentation behaviors, and 21 metabolites were reported for the first time. CONCLUSION: Our findings provide a solid basis for further pharmacologic and pharmacokinetic studies of GTX.

Acetylcholinesterase Inhibitors among Zingiber officinale Terpenes-Extraction Conditions and Thin Layer Chromatography-Based Bioautography Studies.

Although numerous studies have been conducted on ginger extracts and fractions, the data on the pharmacological activity of single constituents of Zingiber officinale are still insufficient. To assess the antidementia properties of the plant, a thin layer chromatography (TLC)-based bioautography acetylcholinesterase inhibitory assay was performed on the Zingiber officinale diethyl ether extract. It led to the recognition of three active inhibitors among volatile constituents of the plant: ar-curcumene (A), α-sesquiphellandrene (B) and a-zingiberene (C). The identification of the components was possible thanks to the application of a TLC-HPLC-MS interface analysis of active zones and the GC-MS qualitative analysis of the tested samples. Based on the obtained results, the influence of several extraction techniques (hydrodistillation-HD, pressurized liquid extraction or accelerated solvent extraction-ASE, shaking maceration-SM, supercritical fluid extraction-SFE, and ultrasound-assisted extraction-UAE) on the recovery of the active metabolites from plant material was assessed to deliver enriched extracts. As a result, HD and SFE, were found to be the most efficient methods to recover the volatile components and the concentrations of A, B, and C reached 0.51 ± 0.025, 0.77 ± 0.045, and 1.67 ± 0.11 percent, respectively. Only HD and SFE were found to recover monoterpene hydrocarbons from the plant matrix. The remaining techniques provided extracts rich in more complex constituents, like sesquiterpenes.

Monitoring removal of hole-hole homodimer by analytical hydrophobic interaction chromatography in purifying a bispecific antibody.

Despite the use of knobs-into-holes (KiH) strategy to promote heterodimerization in recombinant production of bispecific antibody (bsAb), homodimer (especially the hole-hole homodimer) can still be generated in small amount. This by-product needs to be removed by downstream process. However, as homodimer and the target bsAb are usually very close in size, these two species may not be readily differentiated using size-exclusion chromatography-high performance liquid chromatography (SEC-HPLC). Thus, method other than SEC-HPLC needs to be developed to monitor removal of this by-product. Here, through a case study we demonstrate that analytical hydrophobic interaction chromatography (HIC) is a powerful tool for quantitatively monitoring removal of hole-hole homodimer in bsAb purification.

Pharmacokinetic Study of Letrozole Polymorphs in Rats / 医药导报

Objective To study the gastrointestinal absorption process of three letrozole polymorphs in rats, and evaluate the different pharmacokinetics parameters of different polymorphs. Methods A total of 18 SD rats were given the different letrozole polymorphs. Then the high-performance liquid chromatographic method was used for the determination of plasma concentration of letrozole in these SD rats.Finally the pharmacokinetic parameters among the different polymorphs were calculated. Results Cmax of letrozole crystal form I, crystal form II and crystal form III were (9.247± 4.612) ,(23.387± 9.049) and (15.682±1.589) mg·L-1, respectively, and AUC0→t were(198.115±47.014) ,(476.641±125.467) and (271.817±41.068) mg·L-1·h,respectively. Conclusion The different crystal forms of letrozole result in different plasma concentration in SD rats. Crystal form II may be its preponderant polymorphs which deserves further research and development.

Simultaneous Determination of Five Components in Fufang Heishen Oral Liquid by Dual-wavelength HPLC / 医药导报

Objective To establish a method that could detect 5 components of Fufang Heishen oral liquid simultaneously. Methods The component was performed by high performance liquid chromatography ( HPLC) equipped with Agilent Hypersil ODS (4.6 mm×250 mm,5 μm).The mobile phase consisted of acetonitrile-0.1% Phosphoric acid with gradient elution.The flow rate was 1.0 mL·min-1with the 210 nm and 270 nm detection wavelength,20 μL injection volume and 30 ℃column temperature. Results A good linear relationship was observed with the range of 7.12-85.44 mg·L-1for Harpagide (r＝0.999 9),2.50-30.00 mg·L-1for Harpagoside(r＝0.999 8),25.35-304.20 mg·L-1for Cinnamic acid(r＝0.999 7),0.73-8.70 mg·L-1for Tectoridin(r＝0.999 7)and 1.20-14.40 mg·L-1for Irisflorentin(r＝0.999 8).The average recovery of each detected component of Fufang Heishen Oral Liquid was 98.8%,102.7%,98.8%,99.3%,99.9% the RSD were 1.23%,2.89%, 2.60%,1.44%,2.84%(n＝6). Conclusion The method is simple,rapid and accurate and can be used to detect the content of Harpagide,Harpagoside,Cinnamic acid,Tectoridin and Irisflorentin of Fufang Heishen Oral Liquid.

Determination of Nigeglanoside in Seeds of Nigella glandulifera by HPLC / 医药导报

Objective To establish a method for the determination of nigeglanoside in seeds of Nigella glandulifera. Methods The content of nigeglanoside was determined by HPLC.The separation was performed on a C18column ( YMC-Pack ODS-A,250 mm×4.6 mm,5 μm) with a gradient elution system of acetonitrile and 0.017 5 mol·L-1acetic acid solution at the flow rate of 1.0 mL·min-1.The detection wavelength was set at 290 nm,and column temperature was 30 ℃. Results The linear range of nigeglanoside was 0.01-0.30 mg·mL-1(R2＝0.9991).The RSDs of precision,stability and repeatability were all less than 2%.The average recovery was 96.66% (RSD＝1.25%,n＝6). Conclusion The method is accurate and reproducible. It is effective in controlling the quality of seeds of Nigella glandulifera .

Quality Standard of Yinqiao Xiaozhen Mixture / 医药导报

Objective To establish a quality standard of yinqiao xiaozhen mixture. Methods Preparation of Forsyth-ia,Arctium lappa L.,and Honeysuckle were identified by TLC method.The concentration of baicalin in yinqiao xiaozhen mixture was determined by HPLC method. Results The qualitative identification method can detect Forsythia,Arctium lappa L.,and Honeysuckle.TLC spots were clear.TLC method has strong specificity.The linear range of baicalin was 0.122 5-1.531 2 μg,r=0.999 9,the average sample recovery rate was 99.42%,RSD was 2.19%,respectively. Conclusion The method is simple,ac-curate and repeatable,which can be used for quality control of Qinqiao xiaozhen mixture.

Simultaneous Determination of Benzoic Acid and Salicylic Acid in Compound Benzoic Acid Embrocation by High Performance Liquid Chromatography / 医药导报

Objective To develope a high performance liquid chromatography ( HPLC) method for simultaneous determination of benzoic acid and salicylic acid in compound benzoic acid embrocation. Methods An Alltima C18 column (150 mm×4.6 mm,5 μm) was used for the separation, with methanol-0.1％ phosphoric acid (50:50) as the mobile phase at the flow rate of 1.0 mL?min-1 .The detection wavelength was set at 236 nm.The column temperature was 35 ℃ . Results The good linearity was obtained with the correlation coefficient (r) of 1.0000 for benzoic acid and salicylic acid;the precisions and stability were satisfactory, and the relative standard deviations (RSDs) were less than 0.3％.The average recoveries (n= 9) were 100.15％ and 99.85％ for benzoic acid and salicylic acid, respectively. Conclusion The established method is accurate, simple and rapid, and can be utilized for the simultaneous determination of benzoic acid and salicylic acid in compound benzoic acid embrocation.

Percutaneous Absorption of Mupirocin Ointment in Vitro / 医药导报

Objective To compare the percutaneous absorption of experimentally prepared mupirocin ointment and commercially sold mupirocin ointment, and to study the dynamics mode of transdermal absorption of mupirocin ointment. Methods Inerstil ODS-SP column (4.6 mm× 150 mm,5 μm) was used with a mixture of 0.1 mol·L-1 sodium dihydrogen phosphate buffer solution (pH value was adjusted to 6.3 by 0.1 mol·L-1 sodium hydroxide solution) and acetonitrile (75:25) as a mobile phase by HPLC.The detection wavelength was set at 230 nm.The flow rate was 1.0 mL·min-1 .Improved Franz type diffusion cells were used for in vitro permeation studies and excised Obama Suckling pig skins in vitro were used as the transdermal barrier.The concentration of the receptor solution was determined by HPLC to investigate its cumulative permeation quantities at different time and the two sets of ointment were compared. Results The average recovery rate of hydrophilic medium was 99.4％,and RSD was 1.2％(n= 9).The average recovery rate of lipophilic medium was 99.0％,and RSD was 1.3％(n= 9).There was no significant difference of the concentration between two ointment within 12 h.The osmotic release of the drug of the sample and the reference preparation, which were in hydrophilic medium, was similar to that of the Zero equation, and roughly Higuchi equation in the lipophilic medium. Conclusion The results showed that the release behavior of mupirocin ointment followed Zero equation in the hydrophilic medium,and Higchi equation in the lipophilic medium.

Quality Standards of Salt Eucommia Dispensing Granules / 医药导报

Objective To establish the quality standards for salt eucommia dispensing granules. Methods The extractives were obtained by alcohol extraction method. HPLC was applied for the determination of pinoresinol diglucoside in dispensing granules. HPLC fingerprints were established by the contrast of Agilent 1260 HPLC, Waters HPLC and various chromatogram column. Results Pinoresinol diglucoside showed a good linear relationship ( Y = 2. 9594X + 3. 2825,R2 =0.9999) at 102.8-2056.0 mg?L-1 with average recovery of 99.85％ (RSD = 0.31％,n = 9). Conclusion The method is easy-operated and accurate,which has a good specificity for the quality control of common salt eucommia dispensing granules.

Determination of 10-Hydroxyl Carbamazepine in Human Serum by High Performance Liquid Chromatography / 医药导报

Objective To establish a method for the determination of 10-hydroxyl carbamazepine (MHD),which is an activity metabolite of oxcarbazepine in human serum. Methods Serum samples were detected by high performance liquid chromatography (HPLC) after being processed by methanol protein deposition.The chromatographic column was Agilent TC-C18 (4.6 mm × 250 mm, 5 μm), with the mobile phase of acetonitrile-10 mmol ? L-1 KH2 PO4 ( 33 : 67) at a flow rate of 1.0 mL?min-1 .The detection wavelength was 230 nm,and phenacetin was used as an internal standard. Results The average recovery range of low,middle and high (1.0,10.0,60.0 μg?mL-1 ) concentrations for MHD was from 100.3％ to 106.0％.The RSD of intra-day and inter-day was ≤5.8％ (n= 5) and ≤7.4％ (n= 5),respectively.The limit detection of analysis method was 0.1 μg?mL-1 .Regression equation was Y = 0.1308X+ 0.0679 ( r = 0.9966,n = 5). Serum samples remained stable at room temperature,freezing and freeze thawing condition. Conclusion This method is sensitive,accurate,simple and quick,and can be used for monitoring the oxcarbazepine metabolites MHD in serum for clinical and pharmacokinetic study.

Determination of 18β-isomer in Magnesium Isoglycyrrhizinate by HPLC / 医药导报

Objective To establish a HPLC method for determination of 18β-isomer in magnesium isoglycyrrhizinate. Methods The determination was performed by Agilent Extend-C18 column ( 4. 6 mm × 250 mm, 5 μm ) . Mobile phase consisted of 0. 1 mol·L-1 potassium dihydrogen phosphate buffer solution ( adjusted to pH 7. 0 with potassium hydroxide )-acetonitrile (80︰20) at the flow rate of 1.0 mL·min-1. The column temperature was 30 ℃, and the detection wavelength was set at 250 nm. Results The resolution of magnesium isoglycyrrhizinate and 18β-isomer was greater than 2.0. The linear range of them was 0.41-2.46μg·mL-1( r=0.9998) , the detection limit was 0.21 ng, and the average recovery were 100.2%,99.1%, 110.2%,RSD were 0.9%,0.1%,0.2%(n=3). Conclusion The method is simple and accurate, and can be used for determination of 18β-isomer in magnesium isoglycyrrhizinate.

Preliminary Study on Serum Pharmacochemistry of Gentiana rhodantha / 医药导报

Objective To explore the bioactive constituents of Gentiana rhodantha for its serum pharmacochemistry research.Methods The blood migrating constituents of Gentiana rhodantha were determined by comparing the HPLC fingerprints of the aqueous extracts,drug contained serum and blank serum.Results Twenty compounds were detected in drug contained serum,four among which were original constituents of Gentiana rhodantha,the rest might be metabolites of the original ingredients.Conclusion These twenty constituents absorbed in blood could be the bioactive components of Gentiana rhodantha.Further studies will be useful to clarify the bioactive constituents and action mechanisms of Gentiana rhodantha.