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@#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.
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@#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.
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Objective: The present study was undertaken to develop and validate an RP-HPLC method for the combination of imiquimod and salicylic acid Methods: The method was carried out on Nucleodur C18 (250 mm × 4.6 mm I.D., 5 ????m) using low-pressure gradient elution mode. The mobile phase was used as 30M potassium dihydrogen phosphate and acetonitrile (45:55) pH 6.5 adjusted using ortho-phosphoric acid. The concentration of solvents was 1-20 µg/ml and the volume of injection was 20 mcl with the flow rate of 1.0 ml/min. The absorption maxima of salicylic acid and imiquimod were found 234 nm and 226 nm, respectively. Results: The method was validated and showed the linearity greater than 0.99% and with precision (RSD%<1). The limit of detection (LOD) and limit of quantification (LOQ) of salicylic acid was found to be 0.09756 µg/ml and 0.2956 µg/ml, respectively, and imiquimod was found to be 0.044031 µg/ml and 0.13334 µg/ml, respectively. Conclusion: The method developed in the present study was found to be sensitive, specific, and can be applied for the simultaneous estimation of imiquimod and salicylic acid.
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Objective: The objective of the present work was to establish a simple, precise, accurate and robust method for simultaneous estimation of gallic acid, curcumin and piperine from the marketed ayurvedic formulation by liquid chromatography. Methods: The separation was carried out on Hemochrom C18 Column (250 mm × 4.6 mm ID, 5 µm pore size) with a mobile phase methanol: acetonitrile: water (pH 3.2adjusted by using orthophosphate acid) in the ratio 70:20:10v/v by isocratic elution modeat 25 °C and the flow rate was setat0.8 ml/min. The analysis was carried out atisoabsorptive wavelength of 295 nm. Results: The retention time of gallic acid, curcumin and piperine was found to be 3.3(±0.2), 4.7 (±0.2) and 5.6 (±0.2) min, respectively. The linearity range for gallic acid, curcumin and piperine was found to be 10-70 μg/ml, 20-80 µg/ml and 2-14 µg/ml, respectively with the coefficient of linear regression greater than 0.99 for all markers. Mean percent recoveries for gallic acid, curcumin, and piperine were found within the limit of acceptance (99-100%). The percent relative standard deviation (%RSD) for precision and robustness was found less than 2%, which indicates the method is precise and robust. The developed method applied for quantification of these markers from the marketed ayurvedic formulation of Dekofcyn tablet. Conclusion: The developed method was found to be simple, rapid, precise and reproducible for standardization of Dekofcyn tablet and can be useful for other formulations containing these three markers.
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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.
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Objective To find the efficient modification groups of anti-proteinase hydrolyzation in polypeptide by investigat-ing and comparing the relation between the functional groups and their ability to inhibit proteinase hydrolyzation. Methods Reverse phase-high performance liquid chromatography(RP-HPLC)method was developed to investigate in vitro metabolisms of new drug LXT101 and its structural modified analogs LZN series and LMP series in pancreatin system. All the separations of peptide drugs and their digested fragments were monitored at 225 nm. Results The good linear range was 4.0-400 μg/ml(r>0.9990)for new drug LXT101 and its structural modified analogs,i.e.,LZN series and LMP series. The recoveries of all peptide drugs ranged from 95.0%to 98.7%in pancreatin systems. The relative standard derivations(RSD)of intra-day and inter-day were less than 1.5%and 2.5%,re-spectively. The revealed order of digested half-life of the peptide drugs was LZN series>LMP series>LXT101. Conclusion The study of different sites and different functional groups on the lifetime indicates that the half-lives of peptides are prolonged by introducing the functional groups in the suitable sites of peptide,which feature as proteinase inhibitors,such as carbamoyl(Cbm),acetyl(Ac),para-amino-phenylalanine(Aph)or para-uramido-phenylalanine(Uph),which work as either proton donor or acceptor. Our results can pro-vide some useful and valuable information on structural design of peptide drug with long lifetime and high activity.
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Cetuximab (CTX) is a potent chimeric mouse/human monoclonal antibody (mAb) approved worldwide for treatment of metastatic colorectal cancer. Among the various biological and physical analyses per-formed for full study on this biopharmaceutic, the determination of the concentration preparations throughout manufacturing and subsequent handling in hospital is particularly relevant. In the present work, the study and validation of a method for quantifying intact CTX by reverse-phase high-perfor-mance liquid chromatography with diode array detection ((RP)HPLC/DAD) is presented. With that end, we checked the performance of a chromatographic method for quantifying CTX and conducted a study to validate the method as stability-indicating in accordance with the International Conference on Harmo-nization guidelines (ICH) for biotechnological drugs; therefore, we evaluated linearity, accuracy, preci-sion, detection and quantification limits, robustness and system suitability. The specificity of the method and the robustness of the mAb formulation against external stress factors were estimated by compre-hensive chromatographic analysis by subjecting CTX to several informative stress conditions. As de-monstrated, the method is rapid, accurate, and reproducible for CTX quantification. It was also suc-cessfully used to quantify CTX in a long-term stability study performed under hospital conditions.
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Objective: To investigate the changes of matrine concentration in rat local skin with time after transdermal administration of matrine transfersomes, and to evaluate the transdermal delivery properties. Methods: The matrine transfersomes were applied non-occlusively onto rat skin in vivo with abdominal hair removal, and the concentration of drugs in microdialysate of skin was detected by microdialysis and reverse phase high performance liquid chromatography. Furthermore, the concentration-time curves of matrine in microdialysates of skin were compared among marine transfersomes, liposomes, and deoxysodium cholate solution. Results: After the transfersomes were given to rats, the maximum peak time (tmax) of matrine skin concentration appeared at (4.200 ± 0.447) h. The maximum skin concentration (Cmax) was (0.927 ± 0.251) μg/mL and area under the curve (AUC0-8) was (5.033 ± 1.526) μg·h·mL-1, which were much higher than those of the liposomes and the solution (containing 0.8% sodium deoxycholate, P < 0.05), while tmax shortened much more than that of them. Conclusion: In vivo skin microdialysis could be used to assess the transdermal delivery properties of matrine transfersomes. And matrine transfersomes have the good transdermal permeability and efficacy.
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A RP HPLC method for estimation of sildenafil citrate (SC) in tablet dosage form and seminal fluid was developed and validated. Best resolution was obtained with column Waters Spherisorb® C18 bonded silica, (5 μm, 4.6 x 250 mm) at 230 nm with retention time of 5.01 min. The mobile phase used was TEA (0.2%) pH adjusted at 3 with OPA and ACN (60:40) with flow rate of 1.0 mL/min. The method for estimation of sildenafil citrate in tablet dosage form was found to be linear, accurate, precise, sensitive and selective. Whereas the bioanalytical estimation of SC in seminal fluid was found to be in the range of 100 ng/mL to 10μg/mL. Method was found to be highly sensitive as LOD and LOQ were found to 0.3 μg/ml and 0.9μg/ml. The repeatability and reproducibility were within the range i.e. less than 2%.The accuracy of the method was 99.3%. The percentage purity was calculated for market formulation was 102.8%. The internal standard used for bioanalytical methods was Diclofenac sodium. The drug was extracted from seminal fluid by protein precipitation using ACN as precipitating agent. The linearity range was from 100.0ng/mL to 2.0μg/mL. The LOD and LOQ were found to 0.03μg/mL and 0.1μg/mL. The repeatability and reproducibility were within the range i.e. % RSD less than 15%. The accuracy of the method was 90.36%.and the extraction efficiency was found to be 98.25%. The stability of drug was found to be within the range i.e. less the 15%.
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Objective To fractionate phosphoproteome of mouse liver by two-dimensional (2D) liquid phase chromatography fractionation. Methods Phosphoproteins were extracted from lysates of normal mice livers by phosphate metal affinity chromatography (PMAC) resin. The phosphoproteins were exchanged by start buffer and separated by chromatofocusing in the first dimension. Then the fractions between pH 8.5 and pH 4.0 were separated by non-porous silica (NPS) reverse-phase high performance liquid chromatography (RP-HPLC). Finally, the UV maps were converted into gel-like maps by ProteoVue software. Results Phosphoproteins of mouse liver were successfully extracted and fractionated by two dimensional liquid phase chromatographic fractionation after concentration and desalt. Then pI/UV map of mouse liver phosphoproteome was successfully set-up. There are 16 fractions between pH 8.5 and pH 4.0 after chromatofocusing in the first dimension and the UV maps of each fraction were converted into pI/UV gel-like maps. Conclusions Combination of technique of phosphoproteins enrichment and 2-D liquid phase chromatographic fractionation is an effective approach to research phosphoproteome and the key base for further identification and investigation of phosphoproteins.