High-performance Liquid Chromatography-ultraviolet Method Research Articles

High-performance liquid chromatography (HPLC) as a means of assessing the presence of uric acid in archeological human remains: Challenges and future directions.

This research aimed to replicate the Swinson, D., Snaith, J., Buckberry, J., & Brickley, M. (2010). High performance liquid chromatography (HPLC) in the investigation of gout in paleopathology. International Journal of Osteoarchaeology, 20, 135-143. https://doi.org/10.1002/oa.1009 method for detecting uric acid in archeological human remains to investigate gout in past populations and to improve the original High Performance Liquid Chromatography-ultraviolet (HPLC-UV) method by using HPLC-mass spectrometry (HPLC-MS), a more sensitive, compound-specific detection method. We used reference samples of uric acid to create a dilution series to assess the limits of quantification and detection. Samples from individuals with and without gout lesions were taken from foot bones and ribs from the English cemeteries of Tanyard, Hickleton, Gloucester, and Lincoln. We could not replicate the results of Swinson and colleagues using HPLC-UV. Tests using a dilution series of uric acid showed HPLC-MS was approximately 100× more sensitive than HPLC-UV, with the additional benefit of being compound specific. A newly developed hydrophilic interaction chromatography (HILIC) method improved retention characteristics. Fourteen samples from eight individuals, five with skeletal lesions consistent with gout, were analyzed with the final method. None showed evidence of uric acid despite the newly developed method's improved sensitivity and specificity. The lack of detectable uric acid extracted from these samples suggests that (1) urate crystals were not present in any of the bone samples, regardless of gout status; (2) urate crystals did not survive these specific archeological conditions; or (3) the concentration of uric acid in our bone extracts was low, and thus larger samples would be required.

Simultaneous high-performance liquid chromatography analysis of anthraquinones in sicklepod sprouts with α-glucosidase inhibitory activity.

Sicklepod [Cassia obtusifolia L. syn Senna obtusifolia (L.) H.S. Irwin & Barneby, Fabaceae] sprouts are promising ingredients with health-promoting benefits. Notwithstanding, the pharmacologically active compounds in sicklepod sprouts have not been studied or analysed in detail. This study aimed to isolate and structurally identify phytochemicals showing α-glucosidase inhibitory activity in sicklepod sprouts and simultaneously quantify the compounds in the sprouts to determine the optimal cultivation method and germination time to maximise active compounds. A simultaneous high-performance liquid chromatography-ultraviolet (HPLC-UV) method with high sensitivity and accuracy was developed and used to analyse time-dependent changes in anthraquinone content during sicklepod germination. Thirteen anthraquinones were isolated and identified, of which six-chrysoobtusin, emodin, 1-O-methyl-2-methoxychrysophanol, 7-O-methylobtusin, chrysophanol, and physcion-showed moderate α-glucosidase inhibitory activity. The maximum content of anthraquinones in a sprout was observed on Day 5 under both light and dark conditions. The findings of this study revealed that sicklepod sprouts which are promising functional food materials contain a variety of anthraquinones.

Development and Validation of a New High-Performance Liquid Chromatography-Ultraviolet Assay for Quantification of Mitoxantrone in Plasma of BALB/c-nu Mice.

The concentration of mitoxantrone in the blood of mice was determined by a high-performance liquid chromatography-ultraviolet method with aloe-emodin as the internal standard. The separation was performed on a Hypersil BDS2 column (4.6 × 250mm, 5μm) as the analytical column, the mobile Phase A was acetonitrile, and B was 20-mM potassium dihydrogen phosphate (adding 1% triethylamine and adjusting the pH to 2.8 with phosphoric acid) and 4.6-mM sodium octyl sulfonate. The flow rate was 1.0mL·min-1, the detection wavelength was 243nm, the column temperature is 25 ± 5°C and the injection amount was 20μL. Finally, the linear range of mitoxantrone was 5-200μg·mL-1, and the correlation coefficient was r = 0.9999. The recovery rate of the method was 91.93-105.5%, and the extraction recovery rate was 91.45-105.5%. The intraday precision and interday precision were <3.29% (limit of detection = 0.3μg·mL-1). The HPLC method established in this paper was simple, rapid, sensitive and accurate, and can be used to determine the content of mitoxantrone in mouse plasma after tail vein injection.

Optimization and validation of high-performance liquid chromatography using modified QuEChERS to determine anthelmintic drugs in mutton.

The aim of this study was to rapidly determine the presence of anthelmintic drugs in sheep meat using the optimized high-performance liquid chromatography-ultraviolet (HPLC-UV) method with modified QuEChERS (quick, easy, cheap, effective, rugged, safe) technology. Fifty fresh sheep meat samples from different slaughterhouses were collected. A double extraction procedure (QuEChERS/HPLC-UV technology) was used to extract the target analytes. A multilevel calibration curve from 1 to 1000 g/kg was used to establish instrument linearity for rafoxanide, albendazole, and closantel, whereas 0.1-100 μg/kg was used for ivermectin, levamisole, and oxyclozanide to find the lowest concentration, maximum residue limit (MRL), and occupied range for targeted analytes. The concentration levels were used to investigate the linearity, whereas several certified reference materials were applied to determine accuracy. The process was linear for all combinations, from the limit of quantification (LOQ) to the maximum concentration. The LOQ was established at 0.5μg/kg for ivermectin, levamisole, and oxyclozanide and 10μg/kg for rafoxanide, albendazole, and closantel. Recovery values were 70%-120%, and repeatability/reproducibility stated in relative standard deviation was obtained at less than 20%. QuEChERS method revealed that most meat samples contained anthelmintic drug residues, of which the majority exceeded the MRLs. Thus, the drugs should be used correctly in animals to avoid residues in food for human consumption.

Eco-friendly micellar HPLC approach for simultaneous estimation of combination therapy for hidradenitis suppurativa: Applications to spiked human plasma and different dosage forms.

This study introduces a new method for analyzing rifampicin, moxifloxacin, and metronidazole using a green micellar High Performance Liquid Chromatography-Ultraviolet method in bulk drugs, different commercial formulations, and spiked human plasma. The combined therapy of these three broad-spectrum antibiotics is used to cure refractory hidradenitis suppurativa (HS), an inflammatory condition affecting the skin. The sustainable separation was attained on a reversed-phase C18 Kinetex® column maintained at ambient temperature in less than 5 min. The mobile phase comprises 0.1 M sodium dodecyl sulfate (SDS) in water, pH 3.5, adjusted using o-phosphoric acid, and 10% n-butanol. The flow rate was 1 mL/min, with 10 μL injection volume and UV detection at 230 nm. The impact of three key significant variables, SDS concentration, n-butanol percentage, and the mobile phase pH, on suitability parameters was studied. ICH and FDA guidelines were committed to when validating the technique. The results showed linear calibration graphs with high precision and accuracy, in both pure and spiked plasma. The method is efficient, easy to use, and has a high sample throughput, making it suitable for routine analysis in the quality control department and therapeutic monitoring. It is also evaluated as a green-and-white substitute for traditional reported methods.

A Simple HPLC-UV Method for Ivosidenib Determination in Human Plasma.

Ivosidenib is used for the treatment of acute myeloid leukemia (AML) with isocitrate dehydrogenase 1 (IDH1) mutations. However, increased blood concentrations of ivosidenib are associated with a risk of a prolonged QT interval in patients with AML. Therapeutic drug monitoring in patients with AML with IDH1 mutation offers the potential to improve treatment efficacy while minimizing toxicity. In this study, we developed an efficient high-performance liquid chromatography-ultraviolet (HPLC-UV) method for the quantification of ivosidenib in plasma. Human plasma samples (50μL) were processed by protein precipitation using acetonitrile, followed by chromatographic separation on a reversed-phase column with an isocratic mobile phase of 0.5% KH₂PO₄ (pH4.5) and acetonitrile (45:55, v/v) at a flow rate of 1.0mL/min, with ultraviolet detection at 245nm. Calibration curves were linear over the range of 0.25-20μg/mL with a coefficient of determination (r2) of 0.99999. Intra-day and inter-day precision were 1.20-8.04% and 0.69-4.20%, respectively. The assay accuracy was -2.00% to 1.93% and recovery was >91.2%. These findings support the effectiveness of the newly developed HPLC-UV method for the quantification of ivosidenib in human plasma. This simple and cost-effective method is expected to expand ivosidenib monitoring in laboratories lacking LC-MS/MS instruments.

Association Study of Esomeprazole Pharmacokinetics and CYP2C19 Gene Polymorphisms.

To investigate the association between esomeprazole pharmacokinetics and CYP2C19 gene polymorphisms in a cohort of 95 healthy Chinese participants. A cohort of 95 participants was assembled and stratified into 2 distinct groups, receiving either 20 or 40mg of esomeprazole through oral administration. The subjects encompassed 17 poor metabolizers, 47 intermediate metabolizers, and 31 rapid metabolizers, and their genotypes were ascertained using the polymerase chain reaction-restriction fragment length polymorphism technique. Esomeprazole plasma concentrations were quantified employing a high-performance liquid chromatography-ultraviolet method. Pharmacokinetic parameters were computed via Phoenix WinNonlin 6.1 software, while SPSS 26.0 facilitated statistical analysis to contrast the pharmacokinetics and the CYP2C19 genotypes. In the aftermath of administering 20 or 40mg esomeprazole, marked differences were discerned between terminal elimination half-life, maximum concentration/dose, and area under the plasma concentration-time curve from time zero to infinity/dose of esomeprazole (P<.05), with the exception of time to maximum concentration. The findings of this investigation signify a significant association between esomeprazole metabolism and CYP2C19 gene polymorphisms. There were no unprecedented adverse events documented subsequent to the administration of 20 and 40mg esomeprazole dosages. Esomeprazole has manifested promising safety and tolerability profiles in pertinent clinical trials.

Development of a simple high-performance liquid chromatography-ultraviolet method for sotorasib quantification in human plasma: Implications for therapeutic drug monitoring.

Sotorasib, an oral small-molecule inhibitor, reportedly exerts promising activity against Kirsten rat sarcoma viral oncogene homolog (KRAS)-mutant tumors. However, the currently administered dose may fail to represent the optimal dose based on the therapeutic efficacy. Herein, we developed a simple and sensitive method using high-performance liquid chromatography with ultraviolet (HPLC-UV) to measure the sotorasib concentration in human plasma. The sotorasib calibration curve exhibited linearity across the concentration range of 0.10-20.0 μg/mL (r2 = 0.9999). The coefficients of intra- and inter-day validation ranged between 0.79-9.75% and 3.01-6.13%, respectively. The assay accuracy ranged between -3.14 and 5.18%, with > 98.5% recovery. Subsequently, we applied the developed method to estimate sotorasib concentrations in a patient with KRAS G12C-mutated non-small cell lung cancer. We anticipate that our HPLC-UV method will be valuable for assessing the safety and efficacy of sotorasib in larger patient cohorts.

HPLC-UV profiles of Cynanchum auricutalaum, Cynanchum bungei and Cynanchum wilfordii and relationships of their antioxidant activities

The method for simultaneous determination of the two types of principal components, C21- steroids and acetophenones, in Cynanchum bungei, C. auriculatum and C. wilfordii by high-performance liquid chromatography-ultraviolet (HPLC-UV) was developed for the first time. Under the optimized conditions, good linearities (R2≥0.999) were obtained for all analytes, and relative standard deviations (RSDs) of HPLC-UV method validation ranged from 0.01-1.62%. The results of DPPH (1,1-diphenyl 2-picryl hydrazyl) and ABTS (2,2-azobis-3ethylbenzthiazoline-6-sulfonic acid) free radical scavenging assays indicated that the three species had a significant antioxidant activity, with the half maximal effective concentration (EC50) range of 64.56-593.38 μg/mL. Combined with bivariate analysis, the fingerprint-activity relationship of the offline antioxidant activity of the three species with their fingerprints peak was studied, and the results revealed a dose-effect relationship between acetophenones and antioxidant activity. This study provides a theoretical basis for the correct identification and application of the antioxidant activities of C. auriculatum, C. wilfordii and C. bungei.

Qualitative and quantitative study of constituents in Lysionoti Herba based on UHPLC-Q-Exactive Orbitrap HRMS and HPLC-UV

Ultra-high performance liquid chromatography-quadrupole-Exactive Orbitrap high resolution mass spectrometry(UHPLC-Q-Exactive Orbitrap HRMS) was employed to systematically analyze the chemical constituents in Lysionoti Herba, and high perfor-mance liquid chromatography-ultraviolet(HPLC-UV) to determine the content of main compounds. A Synergi~(TM) Hydro-RP 100 Å colu-mn(2 mm×100 mm, 2.5 μm) was used for gradient elution with acetonitrile-0.1% aqueous formic acid as the mobile phase at a flow rate of 0.2 mL·min~(-1) and a column temperature of 40 ℃. MS and MS/MS were conducted with electrospray ionization(ESI) in both positive and negative modes. The chemical components in Lysionoti Herba were identified by comparison with the retention time and mass spectra of reference compounds and the relevant mass spectral data reported in MS databases and relevant literature. Furthermore, the content of five constituents(neochlorogenic acid, chlorogenic acid, forsythoside B, acteoside, and nevadensin) in different Lysiono-ti Herba samples was simultaneously determined by HPLC-UV at the wavelength of 330 nm. A total of 84 compounds were identified in Lysionoti Herba, including 27 flavonoids, 20 phenylethanoid glycosides, 5 amino acids, 18 organic acids, 1 alkaloid, 6 nucleosides, and 7 others. The content of neochlorogenic acid, chlorogenic acid, forsythoside B, acteoside, and nevadensin showed good linear relationship(r&gt;0.999) with the peak area within certain concentration ranges, which were 3.22-102.90, 12.84-410.82, 31.63-1 012.01, 25.00-800.11, and 4.08-130.51 μg·mL~(-1), respectively. The instrument precision, method repeatability, and solution stability all met requirement, and the average recovery rate was 97.31%-100.2%, with RSD ranging from 0.95% to 2.4%. The content of the five components varied among different Lysionoti Herba samples collected from different regions of Guizhou, and the average content of forsythoside B was the highest. The established qualitative method can rapidly and efficiently identify the chemical components of Lysionoti Herba, and the developed HPLC-UV method can simultaneously determine the content of five components in a simple, ra-pid, and accurate manner, providing a scientific basis for the quality evaluation of Lysionoti Herba.

Caffeine content and acidity levels of some non-alcoholic water-based beverages sold in Banda zone, Kampala, Uganda

Background:The consumption of has gained attention due to its ability to promote acute benefits such as improved attention, cognitive performance, reduction of fatigue, increased wakefulness, and analgesia. However, the result of caffeine consumption is a concern, it is important to inform consumers about the caffeine content and acidity levels of all non-alcoholic water-based beverages.Methods:The samples were sonicated and subjected to analysis by high-performance liquid chromatography-ultraviolet method and pH meter method for acidity content. Results: The highest concentration of caffeine was found in energy drink, ED; with 64.01±0.07 mg/L as compared to soft drinks, SD1; 20.20±0.02 mg/L, SD2; 23.14±0.08 mg/L, and SD3; 29.88±0.02 mg/L. All obtained concentrations were below the permissible levels for caffeine (200 mg/L) intake by the United States Food and Drug Administration. The study also showed that all the non-alcoholic beverages were acidic except bottled water in the sequence BW &lt; ED &lt; SD. The categorical range was bottled water; BW2; 8.01±0.03, BW1; 7.5±0.10, BW3; 7.5±0.11, BW4 6.85±1.38, and Energy drink; ED; 3.17±0.01, and finally, soft drinks; SD2; 2.82±0.02, SD1; 2.61±0.02, and SD3; 2.59±0.05. Conclusions: The results obtained in this study provide satisfactory information on the caffeine and acidity contents of the commonly consumed non-alcoholic water-based beverages in Banda, Kampala-Uganda. This in the future could pose serious health risks, since some individuals consume multiple servings of the drinks in a short time, which could result in intoxication/overdose.Keywords: caffeine, soft drinks, energy drinks, public health, Banda

Simple high-performance liquid chromatography-ultraviolet method for simultaneous separation and detection of 14 bisphenol pollutants in building materials.

A high-performance liquid chromatography-ultraviolet method was developed for rapidly and simultaneously analyzing novel and typical bisphenols in building materials, including bisphenol S, diphenolic acid, bisphenol F, bisphenol E, bisphenol A, bisphenol B, bisphenol AF, bisphenol AP, bisphenol C, bisphenol FL, bisphenol Z, bisphenol BP, bisphenol M, and bisphenol P. By using a Kromasil 100-5 C18 column, these bisphenols were completely separated in 40min via gradually increasing the concentration of methanol in the mobile phase from 45 to 80% during the elution process. In particular, this method achieved the synchronous analysis of bisphenol S, diphenolic acid, bisphenol FL, bisphenol BP, and bisphenol M through HPLC, which were difficult to separate and had to be identified and detected through mass spectrometry. The limits of detection of the method ranged from 0.002 to 0.040mg/L for these 14 bisphenols, with a precision of less than 4.9% (n=7, c=0.05mg/L). The analytical results for five types of building materials (phenolic, epoxy, polycarbonate, polyester, and polysulfone resins) indicated that the proposed method is appropriated for the rapid measurement of bisphenols in real samples.

Therapeutic Drug Monitoring in Oncohematological Patients: A Fast and Accurate HPLC-UV Method for the Quantification of Nilotinib in Human Plasma and Its Clinical Application

Nilotinib, a second-generation tyrosine kinase inhibitor, has demonstrated clinical activity in chronic myeloid leukemia. As an exposure-response relationship has been observed for nilotinib, its therapeutic drug monitoring could be a valuable tool in clinical practice. Therefore, the aim of this study was to develop and validate a selective and precise high performance liquid chromatography-ultraviolet method for the measurement of nilotinib in plasma from patients with cancer. After protein precipitation extraction with acetonitrile, nilotinib and rilpivirine were separated using isocratic elution on a Tracer Excel 120 ODS C18 column using a mobile phase consisting of a mixture of potassium dihydrogen phosphate-buffered solution (pH 5.5; 0.037 M)-methanol-acetonitrile (45:45:10, v/v/v), pumped at a flow rate of 1.7 mL·min-1. A wavelength of 254 nm was selected for the quantification of the analyte and the internal standard (IS). The technique was validated following the guidelines for the validation of analytical methods of regulatory agencies (Food and Drug Administration (FDA) and the European Medicines Agency (EMA)). Linearity was established in a concentration range between 125 and 7000 ng/mL. The detection limit was 90 ng/mL, and the lower limit of quantification was 125 ng/mL. For all concentrations in the calibration curve, the intraday and interday coefficients of variation were less than 4.1%. Median recovery of nilotinib from plasma was ≥65.1% (±21.4%). The method described is sensitive, selective, reproducible, and rapid, and can be used for the accurate determination of nilotinib in human plasma for pharmacokinetics studies and for therapeutic drug monitoring (TDM) of nilotinib in routine clinical practice.

High-Performance Liquid Chromatography for Ultra-Simple Determination of Plasma Voriconazole Concentration.

Voriconazole is an antifungal drug used to treat invasive aspergillosis. Voriconazole exhibits nonlinear behavior and considerable individual variability in its pharmacokinetic profile. Invasive aspergillosis has a poor prognosis, and failure of treatment owing to low voriconazole blood levels is undesirable. Thus, therapeutic drug monitoring (TDM) of voriconazole is recommended. However, plasma voriconazole concentration is rarely measured in hospitals, and the TDM of voriconazole is not widely practiced in Japan. We aimed to develop an ultra-simple method to measure plasma voriconazole concentration. Ten microliters of plasma sample was extracted, and proteins were precipitated using methanol extraction. Voriconazole and ketoconazole (internal standard) were separated using high-performance liquid chromatography. A calibration curve was prepared, which was linear over plasma voriconazole concentrations of 0.125–12.5 µg/mL, with a coefficient of determination of 0.9999. The intra-day and inter-day validation coefficients were 0.9–2.2% and 1.3–6.1%, respectively. The assay accuracy was −4.2% to 1.6%, and recovery was >97.8%. Our ultra-simple, sensitive, and inexpensive high-performance liquid chromatography ultraviolet method to determine plasma voriconazole concentration will help improve the voriconazole TDM implementation rate and contribute to effective and safe voriconazole use.

Inosine monophosphate dehydrogenase activity and mycophenolate pharmacokinetics in children with nephrotic syndrome treated with mycophenolate mofetil

Some studies have shown that the area under the concentration-time curve (AUC) of mycophenolic acid (MPA) should be higher for children with nephrotic syndrome (NS) than after renal transplantation. The pharmacodynamic aspect of MPA, the activity of inosine monophosphate dehydrogenase (IMPDH), has not been studied in children with NS. The study included 21 children (4-16 years old) with NS treated with mycophenolate mofetil. MPA and its glucuronide plasma concentrations were determined using validated high-performance liquid chromatography-ultraviolet (HPLC-UV). The separate HPLC-UV method was applied for IMPDH activity determination. The variability was expressed by the coefficient of variation (CV). IMPDH activity and MPA concentration (Ctrough ) before the morning dose amounted to 29.95 μmol s-1 mol-1 adenosine monophosphate (AMP) (range, 6.71-98.60 μmol s-1 mol-1 AMP) and 1.72 μg/mL (range, 0.39-4.34 μg/mL), respectively, whereas the area under the effect-time curve from 0 to 4h and MPA AUC0-4 were 130.36 μmol s-1 mol-1 AMP × h (range, 23.58-306.57 μmol s-1 mol-1 AMP × h) and 24.63 μg h/mL (range, 12.21-67.48 μg h/mL), respectively. IMPDH activity decreased concomitantly with MPA concentration increase, however, the variability of the pharmacodynamic parameters was greater than of the pharmacokinetics. The median degree of maximum IMPDH inhibition was 61%. MPA Ctrough and predicted AUC were lower than in our previous study. Only a few MPA pharmacokinetic parameters correlated with the pharmacodynamics. IMPDH activity did not correlate with the children's age and did not differ between boys and girls. MPA clearance was the highest in younger children (median, 10.54 L/m2 /h) and cholesterol correlated negatively with the children's age (r=-0.659, P=0.003). IMPDH minimum activity and the degree of maximum IMPDH inhibition were similar to those obtained in renal transplant recipients. IMPDH activity does not undergo developmental or gender-specific regulation in children with NS. MPA underexposure might be more frequent in younger children, especially with high cholesterol and triglycerides levels because of high MPA clearance.

Development of a double monitoring system for the determination of Cr(VI) in different water matrices by HPLC-UV and digital image-based colorimetric detection method with the help of a metal sieve-linked double syringe system in complexation.

This study reports a cheap, efficient, sensitive, and simple double monitoring analytical method for trace determination of Cr(VI), which is toxic and harmful even at very low concentrations. A metal sieve-linked double syringe (MSLDS) system was used to help the formation of chromium complex (Cr-diphenyl carbazide, DPC) subsequently determined by high-performance liquid chromatography-ultraviolet (HPLC-UV) and digital image-based colorimetry (DIC) systems. The metal complex was eluted through a Phenomenex-Aqua C18 with a mobile phase comprising of 50mM ammonium formate solution (pH 4.0):acetonitrile (78:22, v/v) and detected by the UV detector at the wavelength of 581nm. Under their optimum conditions, the HPLC-UV and DIC systems exhibited good linearity in ranges of 10-500µg L-1 and 100-1000µg L-1, respectively. The percent relative standard deviations (RSD%s) calculated for the lowest concentrations of both systems fell below 10%, and this confirmed good repeatability for replicate measurements. The accuracy of the proposed methods was evaluated by performing spike recovery experiments on wastewater, river water, and tap water samples. The calculated recovery results were in the range of 81.5-105.5% for HPLC-UV system and 93.8-111.1% for the DIC system. These results indicate that the proposed methods are suitable for routine Cr(VI) determination in terms of their rapidness, simplicity, good repeatability, and low cost.

Assessment of Pharmacokinetic Parameters of Daidzein-Containing Nanosuspension and Nanoemulsion Formulations After Oral Administration to Rats

Daidzein has several biological effects such as antioxidation, anti-inflammation, chemoprevention, and anticancer effects.The aim of this study was to evaluate the impact of nano-formulations (nanoemulsion-NE and nanosuspension-NS) prepared to increase the oral bioavailability of daidzein, a poorly water-soluble isoflavone, on the pharmacokinetic parameters of daidzein in rats. A high-performance liquid chromatography-ultraviolet (HPLC-UV) method was successfully developed for daidzein analysis in rat plasma.The pharmacokinetics studies of the nano-sized formulations, compared to coarse daidzein suspension, were carried out in the rats by a single oral dose at 10 mg/kg (n=6/group). Area under the plasma concentration-time curve from time zero to extrapolation to time infinity (AUC0-∞), maximum plasma concentration (Cmax), time to reach maximum plasma concentration (tmax), andelimination half life (t1/2)values for coarse daidzein suspension, daidzein-NS, and daidzein-NE were estimated by a non-compartmental analysis. The AUC values of daidzein-NE and daidzein-NS were approximately 2.62 and 2.65 times higher than that of coarse daidzein suspension, respectively (p<0.05). Relative bioavailability (Frel) (%) values of daidzein following oral administration of nanosuspension or nanoemulsion formulations were about 265.6% and 262.3%, respectively. It revealed that nanoscale size is an important factor to overcome any dissolution rate barriers to oral bioavailability of the low water-soluble compound. Nanoemulsion and nanosuspension formulations are beneficial dosage forms to increase the oral bioavailability of Biopharmaceutical Classification System (BCS) Class II and Class IV compounds.

Assessment and quantification of homovanillic acid and vanillylmandelic acid in rodent urine samples using a validated high-performance liquid chromatography-ultraviolet method

Objective: The purpose of this study was to establish a validated analytical method for estimating the biogenic amine metabolites vanillylmandelic acid (VMA) and homovanillic acid (HVA) simultaneously using the high-performance liquid chromatography-ultraviolet (HPLC-UV) method. Materials and Methods: For the analysis of VMA and HVA in artificial urine samples, an HPLC method was devised and validated. The chromatographic separation was achieved on Kromasil C8, 5 μm (125 mm × 4.6 mm) column at an ambient temperature of 25°C, with mobile phase combination of acetonitrile: 0.1% orthophosphoric acid in ratio of 30:70 v/v at a flow rate 0.5 mL/min using Agilent HPLC system. For the separation of these two metabolites, different mobile phases were used on a trial and error basis. In terms of linearity, accuracy, repeatability, precision, and robustness, the developed technique was validated according to ICH guidelines. Results: A high-resolution HPLC method was devised for the separation of VMA and HVA. VMA and HVA were found to be linear over the concentration range of 10 to 35 μg/mL, with coefficients of determination (r2) of 0.955 and 0.963 for both metabolites, respectively. VMA and HVA had detection limits of 1.7 and 1.8 μg/mL, respectively, and quantification limits of 5.2 and 5.3 μg/mL. The results showed a low value of % relative standard deviation for repeatability, intra- and inter-day precision, and robustness studies. Conclusion: A validated HPLC-UV method was developed for estimating VMA and HVA in urine samples.

Pharmacokinetics and tissue distribution characteristics of the novel photosensitizer 32-(4-methoxyphenyl)-152-aspartyl-chlorin e6

二氢卟吩类衍生物32-(4-甲氧基苯基)-152-天冬氨酸-二氢卟吩e6(DYSP-C34)是从程海湖螺旋藻中提取并合成的新型光敏剂。研究DYSP-C34在生物体内的药代动力学及组织分布过程对光动力疗法(PDT)的有效性和安全性至关重要。该文运用高效液相色谱-紫外(HPLC-UV)检测技术,建立了大鼠血浆中DYSP-C34的检测方法。采用沉淀蛋白-液液萃取法处理血浆和组织样品,采用Unitary C18色谱柱(250 mm×4.6 mm, 5 μm)分离,流动相为甲醇-5 mmol/L四丁基磷酸氢铵缓冲盐溶液(70:30, v/v),流速为1.0 mL/min,进样量为20 μL,检测波长为400 nm,柱温为40 ℃。实验结果表明,大鼠血浆药物质量浓度在1~200 μg/mL范围内线性良好,判定系数(r2)为0.9941。在低、中、高(8、40、120 μg/mL)3个添加水平下的提取回收率分别为74.39%、69.71%和65.89%,日内和日间相对标准偏差(RSD)均在5%以内。运用此方法测定静脉注射DYSP-C34(16 mg/kg)后大鼠血浆中以及荷瘤小鼠组织中的药物浓度,采用DAS 2.0计算出药物半衰期t1/2z为6.98 h,药-时曲线下面积AUC(0-∞)为1025.01 h·mg/L,平均驻留时间MRT(0-∞)为9.19 h。DYSP-C34在荷瘤小鼠体内的分布结果显示,DYSP-C34可以在肿瘤组织中蓄积,并具有一定的滞留作用。综上,该文建立了大鼠血浆中DYSP-C34的HPLC-UV测定方法,并进行了方法学验证,此方法简便、快速,结果准确。阐明了DYSP-C34在静脉给药方式下大鼠体内药代动力学和荷瘤小鼠组织中的分布特征,对临床合理用药和药效学研究具有重要意义。

STATISTICALLY OPTIMIZED AND BOX-BEHNKEN DESIGN ASSISTED METHOD DEVELOPMENT AND VALIDATION OF AN ANTIPSYCHOTIC MEDICATION OLANZAPINE AND ITS RELATED IMPURITIES BY REVERSE-PHASE HPLC-UV SPECTROSCOPY

Objective: Statistically designed and Box-Behnken design (BBD) assisted reversed-phase high-performance liquid chromatography-ultraviolet (HPLC-UV) method was developed and validated for the identification of an antipsychotic medication Olanzapine and its organic impurities in pure drug along with forced degradation studies.&#x0D; Methods: The present developed method employed BBD optimized chromatographic conditions comprising of an Inertsil ODS 3V analytical column with dimension 250 mm x 4.6 mm and particle size 5µ. The isocratic mobile phase was used as a mixture of monobasic sodium phosphate buffer (0.01 M, pH 6), methanol and acetonitrile in the proportion of 40/30/30, v/v. The mobile phase flow rate and UV λmax was 1 ml/min and 260 nm, respectively. The method was optimized by Box-Behnken design using design expert software, comprising of three factors for Olanzapine for instance flow rate (A), mobile phase composition (B) and pH (C) while resolution between Olanzapine related compound A and Olanzapine related compound B (Y1) and tailing of Olanzapine (Y2) were taken as a response.&#x0D; Results: Application of BBD yielded statistically designed method with excellent quality parameters achieved in terms of linearity with the coefficient of correlation (R2&gt;0.9999), limit of detection (LOD, 0.0023-0.16 µg/ml), the limit of quantification (LOQ, 0.007-0.39 µg/ml), accuracy (99-100%) and precision ((2%, relative standard deviation (%RSD) were evaluated as per latest available procedures.&#x0D; Conclusion: Forced degradation conditions were carried out, demonstrated that the optimized method was stable and no any interfering peaks eluting at the similar retention time of the studied compounds. The method was found to be stable, easy, rugged and robust, could be applied for the similar types of the pure drug.