Development and verification of pre-column derivatization reverse phase-high performance liquid chromatography for determination of Glycine and Histidine content in recombinant proteins / 中国生物制品学杂志

@#Objective To develop and verify a pre-column derivatization reverse phase-high performance liquid chromatography(RP-HPLC) method for determination of Glycine and Histidine content in recombinant proteins.Methods AccQ Tag-C 18(3.9 mm × 150 mm,4 μm) column was used as chromatographic column,6-aminoquinolyl-N-hydroxysccinimidyl carbamate(AQC) was used as pre-column derivatization reagent,while α-aminobutyric acid as internal standard.AccQTag Eluent A solution,acetonitrile solution and high-purity water were used as mobile phases.The UV detection wavelength was 248 nm,injection volume was 10 μL,flow rate was 1.0 mL/min,and column temperature was 37 ℃.The contents of Glycine and Histidine in samples were determined by the internal standard method,and the specificity,linearity,detection limit,quantitative limit,precision,accuracy and stability of the method were verified.Results The developed method effectively separated Glycine,Histidine and internal standard α-aminobutyric acid with high specificity.The standard curves of Glycine in the range of 2.25～11.25 μg/mL and Histidine in the range of 72.85～364.24 μg/mL showed good linearity,each correlation coefficient(R~2) 0.99.The detection limits were 2.25 μg/mL for Glycine and 18.21 μg/mL for Histidine.The quantitative limits were 4.69 μg/mL for Glycine and 32.86 μg/mL for Histidine.The relative standard deviation(RSD) of 6 replicates with the same concentration of Glycine and Histidine were 4.6% and 5.0%,and the RSD of recovery rate in intermediate precision test was 6.9% and 2.0%,respectively.The content of Glycine was close to the quantitative limit,and the average recoveries of high,medium and low concentrations of samples were within 75.9%～111.7%;The recoveries of Histidine ranged from 88.9% to 97.3%.The RSD of Glycine content and Histidine content was 7.7% and 3.3% respectively at 0,12,18,24,30 and 48 h in the same sample.Conclusion The pre-column derivatization RP-HPLC method has accurate and reliable results with high precision,which might be used for quality control of Glycine and Histidine content in recombinant proteins.

Development and validation of reverse phase-high performance liquid chromatography for determination of residual N-hydroxy succinimide content in semaglutide / 中国生物制品学杂志

@#Abstract： Objective To develop and validate a reverse phase⁃high performance liquid chromatography（RP⁃HPLC） method for determination of residual N⁃hydroxy succinimide（NHS）content in semaglutide. Methods A RP⁃HPLC method was developed based on the screening of chromatographic column and optimization of mobile phase（phosphate concentration and the ratio of acetonitrile），validated for specificity，suitability，accuracy，reproducibility and stability， and determined for linear range，limit of quantitation（LOQ）and limit of detection（LOD）. The NHS contents in three batches of semaglutide were determined by the developed method. Results The optimal condition for RP⁃HPLC was as follows：CAPCELL PAK ADME column（4. 6 mm × 150 mm，3 μm）was adopted，serving 0. 05 mol／L potassium dihy⁃ drogen phosphate solution⁃acetonitrile（98∶2）as mobile phase A，and 70% acetonitrile as mobile phase B with gradient elution（0 min，0% B；10 min，0% B；19 min，90% B；19. 1 min，0% B；25 min，0% B）at a flow rate of 0. 8 mL／min. The detection wave length was set at 260 nm，while the column temperature was 30 ℃. The developed method showed good specificity and systemic suitability，of which the linear range was 0. 2 ~ 3. 0 μg／mL（R2 = 1. 000 0），while the LOD and LOQ were 4. 8 and 9. 6 ng respectively. The RSD of recovery rates of NHS samples at three concentrations was 0. 58%， indicating a high accuracy. The RSD of NHS contents in six test samples was 0. 16%，indicating a high reproducibility. The RSD of peak areas of NHS after storage at room temperature for 0，4，8，12，16，20 and 24 h was 0. 34%，indicating a high stability. No NHS was detected in three batches of semaglutide by the developed method. Conclusion The developed RP⁃HPLC method is simple and sensitive，which may be used for the determination of NHS content in semaglutide.

Identification of RNAi hypoallergic bread wheat lines for wheat-dependent exercise-induced anaphylaxis patients.

Wheat-dependent exercise-induced anaphylaxis (WDEIA) is one of the most severe forms of wheat allergy. It occurs in patients when they exercise after ingesting wheat-containing foods. Nowadays, the only possible alternative for WDEIA patients is to avoid such foods. This study investigated the potential of six RNA of interference (RNAi) wheat lines with low-prolamin content as alternatives for WDEIA patients. For that purpose, a high performance-liquid chromatography (HPLC) analysis was performed to evaluate differences in gluten protein fractions among these lines. Next, western blots were conducted to measure the immunoglobulin E (IgE) reactivity to wheat proteins in sera from five WDEIA patients. Additionally, monoclonal antibodies (moAb) recognition sites and the IgE binding sites were searched in all peptides identified by LC-MS/MS after protein digestion. The results showed a 61.4%-81.2% reduction in the gliadin content of the RNAi lines, accompanied by an increase in their high-molecular weight (HMW) glutenin content compared to the wild type bread wheat line (WT). In all cases, the reduction in gliadin content correlated with a decrease in IgE reactivity observed in the sera of WDEIA patients, highlighting the E82 and H320 lines. These two RNAi lines exhibited a ≤90% reduction in IgE reactivity. This reduction could be attributed to an absence of IgE binding sites associated with α- and ω5-gliadins, which were present in the WT. Overall, these lines offer a potential alternative for foodstuff for individuals with WDEIA.

Application of Natural Deep Eutectic Solvents in the Extraction of Quercetin from Vegetables.

Quercetin is a phytochemical with disease prevention and health promotion activities that has attracted significant research attention. In this study, choline chloride and betaine-based natural deep eutectic solvents were prepared using a heating method. Their physical and chemical properties were also tested. Then, they were applied to extract quercetin from onion and broccoli with ultrasonic-assisted solid liquid method coupled with HPLC. Three factors (temperature, amount, and time) were considered for the optimization of the extraction assays. In the optimal conditions, the extraction recoveries were 88.91-98.99%, 88.45-99.01%, and 89.56-98.74% for quercetin, isorhamnetin, and kaempferol. Tailor-made natural deep eutectic solvents could be applied as sustainable and safe extraction media for biochemical applications.

[Impurity profile of macitentan in tablet dosage form using a stability-indicating high performance liquid chromatography method and forced degradation study].

Macitentan (MAC) is a pulmonary arterial hypertension (PAH) drug marketed as a tablet and often has stability issues in the final dosage form. Quantitative determination of MAC and its associated impurities in tablet dosage form has not been previously reported. This study quantified impurities present in Macitentan tablets using a binary solvent-based gradient elution method using reversed phase-high performance liquid chromatography. The developed method was validated per International Conference on Harmonization (ICH) guidelines and the drug product was subjected to forced degradation studies to evaluate stability. The developed method efficiently separated the drug and impurities (48 min) without interference from solvents, excipients, or other impurities. The developed method met all guidelines in all characteristics with recoveries ranging from 85%-115%, linearity with r2 ≥ 0.9966, and substantial robustness. The stability-indicating nature of the method was evaluated using stressed conditions (hydrolysis:1 N HCl at 80℃/15 min; 1 N NaOH at 25℃/45 min; humidity stress (90% relative humidity) at 25℃ for 24 h, oxidation:at 6% (v/v) H2O2, 80℃/15 min, thermolysis:at 105℃/16 h and photolysis:UV light at 200 Wh/m2; Fluorescent light at 1.2 million luxh). Forced degradation experiments showed that the developed method was effective for impurity profiling. All stressed samples were assayed and mass balance was>96%. Forced degradation results indicated that MAC tablets were sensitive to hydrolysis (acid and alkali) and thermal conditions. The developed method is suitable for both assay and impurity determination, which is applicable to the pharmaceutical industry.

Comparative Analysis of Protein Quantification Methods for the Rapid Determination of Protein Loading in Liposomal Formulations.

Advances in manufacturing processes provide the ability for the high throughput production of liposomes containing a range of moieties, from small molecules to large biologicals (including proteins and nucleic acids for prophylactic and therapeutic applications). Whilst rapid quantification methods for small molecules are generally well established, the ability to rapidly quantify liposomal entrapment of proteins is limited. Indeed, most standard protein quantification techniques (including the BCA assay and Reverse phase-high performance liquid chromatography (RP-HPLC)) measure protein encapsulation indirectly, by measuring the amount of non-incorporated drug, and subtracting from the initial amount of protein added. However, this can give inaccurate and misrepresentative results. To address this, we have developed a range of methods to directly quantify protein entrapment within liposomes. The encapsulation efficiency within neutral, anionic and cationic liposome formulations was determined by three techniques; BCA assay, RP-HPLC and HPLC coupled to an evaporative light scattering detector, (HPLC-ELSD). All three methods are reliable for the quantification of protein, with linear responses and correlation coefficients of 0.99, and LOQ for all three methods being less than 10 µg/mL. Here within, we provide three methods for the rapid and robust quantification of protein loading within liposomal (and other bilayer) vesicle systems.

Metabolite characterization of powdered fruits and leaves from Adansonia digitata L. (baobab): A multi-methodological approach.

The metabolite profiling of extracts from Adansonia digitata L. (baobab) fruit pulp and leaf, and the quantification of their major components, was conducted by means of reverse-phase, high-performance liquid chromatography with photodiode array detection, coupled to electrospray ion-trap mass spectrometry (RP-HPLC-PDA-ESI-MS/MS) and high field nuclear magnetic resonance (NMR) spectroscopy. Water-soluble metabolites from chemical classes including sugars, amino acids, organic acids, and phenolic compounds, were identified, in addition to metabolites soluble in organic solvents such as triacylglycerides, sterols, and fatty acids, and most of these were quantified. The profiling of the primary and secondary metabolites of baobab fruit and leaves addresses the limited knowledge of the chemical composition of baobab, and helps support and explain the growing evidence on its nutritional and biological properties, and provide suggestions about the possible uses of baobab fruit and leaves by food, pharmaceutical and cosmetic industries.

Identification and characterization of flavor precursor peptide from beef enzymatic hydrolysate by Maillard reaction.

In this study, beef enzymatic hydrolysate was fractionated by sequential UF/GFC/RP-HPLC. RP-HPLC fractions were subjected to Maillard reaction with xylose. The FD/TD factors of the MRPs were prominent. Sensory evaluation showed that F-3 exhibited intense meaty taste; the kokumi intensity, umami-enhancing capacity in F-4; the umami-enhancing capacity in F-5; the umami intensity and umami-enhancing capacity in F-6. All these were strong in F-7 and F-8. The RP-HPLC fractions were subsequently analyzed by ESI-Q-TOF MS/MS. Of the 21 peptides identified, Leu(Ile)-X, Val-X, Phe-X, and Cys-containing peptides were the major ones. Six peptides (Leu-Cys, Glu-Cys-Gly, Cys-Gly-Val, Val-Met, Phe-Glu, and Phe-Gln) were synthesized and included in the Maillard reaction with xylose. FD factors of MRPs of all these synthesized peptides were significantly greater than those of fraction F-7. The stronger Maillard reactivity demonstrated by the synthesized peptides proves that this work is correct.

Reverse phase high-performance liquid chromatography (RP-HPLC) system for analysis of vitamin D3 soft capsules with soybean oil matrix / 复旦学报（医学版）

Objective To develop a method for the determination and impurity analysis of vitamin D3 soft capsules with soybean oil matrix in reverse phase high performance liquid chromatography (RP-HPLC) system.Methods RP-HPLC system had Agilent Zorbax Eclipse XDB-C18 column (4.6 mm × 250 mm,5 ttm) with detection wavelength of 265 nm,column temperature of 25 ℃ and flow rate of 1 mL/min.Retention behaviors of vitamin D3 and its 3 isomers were studied by altering the mobile phase.Firstly,acetonitrile was mixed with different proportions of methanol,water and ethanol as the mobile phase to investigate the effects of these 4 mobile phase components on the retention behavior of vitamin D3 and its 3 main related substances (isomers) on a C18 column.Then,a suitable mobile phase was selected for content determination and impurity analysis according to the retention behavior study.Results The recovery was only 80.55％-84.37％ with 100％ acetonitrile as the mobile phase.The addition of ethanol in acetonitrile was found to make remarkably significant improvement.Recovery rate was achieved between 98.07 ％ and 103.23 ％ with V (acetonitrile) ∶V (ethanol) =90∶10 as the mobile phase,while improving pealk shape.The method showed good linearity [(0.52-5.2) x 10-4 t mol/L,R2＞0.999] and fine density (RSD＜2.32％) which can be used for determination.For impurities profile,it could be achieved using V (acetonitrile):V (water) =95:5 as the mobile phase which can obviate interference from soybean oil matrix.Conclusions The method established in this experiment can easily and accurately determine the content and impurity analysis of vitamin D3 soft capsules with soybean oil matrix in a RP-HPLC system.

Process for production and purification of Lethal Toxin Neutralizing Factor (LTNF) from E. coli and its economic analysis.

BACKGROUND: Purification of peptides offers unique challenges with respect to obtaining the desired process yield and selectivity. Lethal Toxin Neutralizing Factor (LTNF) is a peptide that is known to neutralize snake venom in mice when the peptide is preincubated with the venom prior to intravenous injection. A process for producing highly purified recombinant LTNF has been developed. The process has been modelled in SuperPro designer using laboratory data for a plant capable of producing 10 Kg of purified rLTNF. Economic analysis has been performed for manufacturing 3 ton of purified rLTNF. RESULTS: The process developed produces peptide in the form of concatemer that has been specifically designed to accumulate as insoluble inclusion bodies (IB) during expression in E. coli. A cation exchange chromatography step has been developed to capture the rLTNF concatemer at 140 g/L dynamic binding capacity. Further, the purified concatemer is cleaved completely into monomeric rLTNF using alpha-chymotrypsin enzyme. Finally, a reversed phase high performance liquid chromatography has been designed to purify rLTNF with a recovery of more than 90% and purity greater than 98%. The overall process recovery is 78±2% resulting in 3.36 g of purified product per batch. Techno-economic evaluation of the process has been performed to demonstrate its economic feasibility against currently marketed antivenom products. CONCLUSIONS: The developed process is able to produce purified rLTNF with 78±2% recovery. The study shows that recombinant technology can be used to produce rLTNF cost effectively and shows potential as a substitute for currently available antivenoms against snakebite.

Determination of urazamide in pharmaceutical preparation with room temperature ionic liquid.

A high performance liquid chromatographic method was developed and validated for the determination of urazamide in pharmaceutical preparation with novel green aqueous mobile phase modified with room temperature ionic liquids (RTILs). 1-Ethyl-3-methyl-imidazolium tetrafluoroborate ([EMIM][BF4]) was selected as a mobile phase additive to improve retention and avoid baseline disturbances at t0. Various mobile phase parameters such as cation moiety, chaotropic anion moiety, pH and concentration of RTILs were optimized to determine urazamide at the proper retention time. The assay was validated according to International Conference on Harmonization guidelines. The linearity of the calibration curve was good (r2 > 0.999). Intra-day precision varied between 0.50 and 1.23%. Relative standard deviations of inter-day precision ranged between 1.07 and 1.66%. Recoveries in tablets ranged between 99.7 and 101.2% and it was successfully applied to determine urazamide in pharmaceutical preparations.

Extraction of polyphenols in Himanthalia elongata and determination by high performance liquid chromatography with diode array detector prior to its potential use against oxidative stress.

Several studies have demonstrated the antioxidant capacity of seaweeds, which can be used for the development of biopharmaceuticals with extensive medical application. Antioxidant therapies appear to attenuate the organic deterioration originated by an excessive oxidative stress, which could prevent the harmful effects of various injuries such as ischemia-reperfusion (I/R) among others. Marine brown seaweeds play a significant role, as they are the only organisms on earth producing phlorotannins, which are polyphenols that exhibit important biological activity. To ensure obtaining an extract with the greatest antioxidant activity, some variables that affect the extraction of polyphenols are optimized, including seaweed amount, type of solvent, and time and temperature of extraction. Subsequently, the total phenolic content (TPC) and the antioxidant activity have been determined. The optimized condition was obtained for 6g of seaweed, ethanol: water proportion of 60:40 and 2h/60°C, achieving 548.33mg AG/100g seaweed and 76% of antioxidant activity. The characterization of the extracted polyphenols was made by HPLC/DAD. 11 polyphenols were identified in the extract: Phloroglucinol, Gallic Acid, Catechin, Rutin, Gentisic Acid, Chlorogenic Acid, Caffeic Acid, Coumaric, Ferulic, Myricetin and Quercetin.

Offline solid-phase extraction for preconcentration of pharmaceuticals and personal care products in environmental water and their simultaneous determination using the reversed phase high-performance liquid chromatography method.

The present study reports a precise and simple offline solid-phase extraction (SPE) coupled with reversed-phase high-performance liquid chromatography (RP-HPLC) method for the simultaneous determination of five representative and commonly present pharmaceuticals and personal care products (PPCPs), a new class of emerging pollutants in the aquatic environment. The target list of analytes including ciprofloxacin, acetaminophen, caffeine benzophenone and irgasan were separated by a simple HPLC method. The column used was a reversed-phase C18 column, and the mobile phase was 1 % acetic acid and methanol (20:80 v/v) under isocratic conditions, at a flow rate of 1 mL min(-1). The analytes were separated and detected within 15 min using the photodiode array detector (PDA). The linearity of the calibration curves were obtained with correlation coefficients 0.98-0.99.The limit of detection (LOD), limit of quantification (LOQ), precision, accuracy and ruggedness demonstrated the reproducibility, specificity and sensitivity of the developed method. Prior to the analysis, the SPE was performed using a C18 cartridge to preconcentrate the targeted analytes from the environmental water samples. The developed method was applied to evaluate and fingerprint PPCPs in sewage collected from a residential engineering college campus, polluted water bodies such as Nag river and Pili river and the influent and effluent samples from a sewage treatment plant (STP) situated at Nagpur city, in the peak summer season. This method is useful for estimation of pollutants present in microquantities in the surface water bodies and treated sewage as compared to nanolevel pollutants detected by mass spectrometry (MS) detectors.

Validation of a high performance liquid chromatography method for the stabilization of epigallocatechin gallate.

Epigallocatechin gallate (EGCG) is a green tea catechin with potential health benefits, such as anti-oxidant, anti-carcinogenic and anti-inflammatory effects. In general, EGCG is highly susceptible to degradation, therefore presenting stability problems. The present paper was focused on the study of EGCG stability in HEPES (N-2-hydroxyethylpiperazine-N'-2-ethanesulfonic acid) medium regarding the pH dependency, storage temperature and in the presence of ascorbic acid a reducing agent. The evaluation of EGCG in HEPES buffer has demonstrated that this molecule is not able of maintaining its physicochemical properties and potential beneficial effects, since it is partially or completely degraded, depending on the EGCG concentration. The storage temperature of EGCG most suitable to maintain its structure was shown to be the lower values (4 or -20 °C). The pH 3.5 was able to provide greater stability than pH 7.4. However, the presence of a reducing agent (i.e., ascorbic acid) was shown to provide greater protection against degradation of EGCG. A validation method based on RP-HPLC with UV-vis detection was carried out for two media: water and a biocompatible physiological medium composed of Transcutol®P, ethanol and ascorbic acid. The quantification of EGCG for purposes, using pure EGCG, requires a validated HPLC method which could be possible to apply in pharmacokinetic and pharmacodynamics studies.

Reverse-phase HPLC analysis and purification of small molecules.

Reversed phase high-performance liquid chromatography (HPLC) is utilized for the separation of molecules due to their polarity in order to quantify, identify, and/or purify various samples such as those from serum, human and animal tissues, drugs, and foods. The following protocols are for extracting carotenoids from samples and subsequent HPLC analysis. If you are interested in another compound for HPLC analysis, Sigma-Aldrich® has a wonderful online resource for multiple adaptations to the HPLC protocol for the analysis of hundreds of compounds (see References).

Concurrent Estimation of Clopidogrel Bisulfate and Aspirin in Tablets by Validated RP-HPLC Method.

A simple, rapid, precise RP-HPLC method was developed for simultaneous estimation of aspirin and clopidogrel bisulphate in tablet dosage form used in the treatment of cardiovascular diseases. To achieve the maximum resolution, acetonitrile:50 mM potassium dihydrogen phosphate buffer:methanol, solution pH adjusted to 3, in the ratio 50:30:20; v/v was selected as mobile phase. This mixture was found to be appropriate allowing good separation of both the components at a flow rate of 1.5 ml/min and detection wavelength 240 nm. In these conditions clopidogrel bisulfate and aspirin were eluated at the 7.47 and 2.2 min. The linearity was found in the concentration range 1.5-7.5 and 3.5-15.0 µg/ml, respectively. All the analytical validation parameters were determined and found with in the limit as per ICH guideline, which indicates the validity of method.