RSD Percentage Research Articles

Development of Novel Cobalt Tungstate Anchored on MCM-41 for Sensitive Detection of Dopamine in Human Urine Samples

In this study, MCM-41/CoWO4 nanocomposite has been used for electrochemical detection of dopamine neurotransmitters. The cobalt tungstate nanoparticles (CoWO4) were synthesized through facile hydrothermal method and MCM-41/CoWO4 nanocomposite was prepared by ultrasonication method. The as-synthesized MCM-41/CoWO4 nanocomposite was characterized by X-ray diffraction, scanning electron microscopy, energy-dispersive X-ray spectroscopy, and Raman techniques. The electrochemical performance of the nanocomposite was examined using electrochemical impedance spectroscopy, cyclic voltammetry, and differential pulse voltammetry studies. The GCE/MCM-41/CoWO4 electrode exhibited a linear range, better sensitivity, and limit of detection (LOD) of 10–170 μM, 0.3361 μA μM−1 cm−2 and 7.2 nm, respectively. Moreover, the GCE/MCM-41/CoWO4 electrode demonstrated good repeatability, reproducibility, and stability. In addition to that, the real sample analysis was conducted using human urine with excellent recovery and RSD percentage.

Development and Validation of RP-HPLC Analysis Method for Determination of Total Alkaloid Content of Soursop (Annona muricata L.) Leaf Extract

Soursop leaves contain alkaloids that have pharmacological effects. This study aims determine the total alkaloid content of soursop leaf ethanol extract using a validated HPLC method. Extraction was carried out by soxhletation followed by liquid-liquid extraction using chloroform. Optimizing HPLC conditions on the mobile phase, flow rate, concentration, and wavelength, further testing the validation of the analytical method. Optimizing HPLC conditions obtained optimal results at concentration of 500 ppm with a flow rate of 1.0 mL/min using acetonitrile: methanol: water (80:5:15) at wavelength of 272 nm. These results have met the validation requirements of analytical methods including System Suitability Test (UKS), selectivity, linearity with y = 2.01914x –219,97226, correlation coefficient value (r) = 0.9995, and Vx0 value 0.11201%. The limit of detection and quantization were 8,78525 ppm and 29,28418 ppm, respectively. The RSD percentage of the precision test is 1.0453%, and the accuracy test is obtained from the recovery of 98-102%. The result of determining the total alkaloid content sample was 0.0862 ± 0.004 % (%w/w) of the entire alkaloid content (TALC) triple replication. This research concludes that the analytical method using the HPLC system for determining the total alkaloid content of the ethanolic extract of soursop leaves is validate

VALIDASI METODE ANALISIS SENYAWA ETIL p-METOKSISINAMAT DALAM PLASMA DARAH TIKUS PUTIH JANTAN GALUR WISTAR MENGGUNAKAN KROMATOGRAFI CAIR KINERJA TINGGI

Ethyl p-methoxycinnamate (EPMC) isolated from the rhizome of kencur (Kaempferia galanga L) is being developed at STFI. Validation of EPMC analysis in blood plasma using High-Performance Liquid Chromatography (HPLC) needs to be conducted to perform in vivo EPMC analysis. This study aims to validate the EPMC analysis method in blood plasma using HPLC. The HPLC column used is column C18, with methanol : phosphoric acid 70:30 and 80:20 mobile phases, a flow rate of 1.0 mL/min, and a maximum wavelength of 310 nm. The blood plasma used was the blood plasma of white male rats of the Wistar strain. EPMC was added to blood plasma and analyzed using HPLC. Parameter validation used is system suitability test, linearity, accuracy, precision, limit of detection (LOD), and limit of quantification (LOQ). The results showed that the optimum mobile phase for analyzing EPMS in plasma was methanol : phosphoric acid with a ratio of 70:30. Based on the validation, the linear regression was 0.998. In the accuracy test, the average value range for the percent recovery is 98% - 102%. In the precision test, the average value of the RSD percentage was 4.10% - 68.83%. The LOD value is 2.747 g/mL, and the LOQ value is 9.158 g/mL. Based on this research, it can be concluded that EPMC in blood plasma can be analyzed using KKKT with column C18 and mobile phase methanol : phosphoric acid 70:30.

Development and validation of UV chromatographic method for quantification of copper and copper nanoparticles in different matrices and pharmaceutical products

Background The applications of Cu and CuNPs based on the earth-abundant and inexpensive Cu metal have generated a great deal of interest in recent years, including medical applications. A novel, specific, precise, accurate and sensitive reverse-phase high-performance liquid chromatography (RP-HPLC) method with UV detection has been developed and validated to quantify copper (Cu) and copper nanoparticles (CuNPs) in different biological matrices and pharmaceutical products. Methods The developed method has been validated for linearity, precision, sensitivity, specificity and accuracy. Cu concentration was detected in pharmaceutical products without an extraction process. Moreover, liver, serum and muscle tissues were used as biological matrices. High Cu recovery in biological samples was afforded by using citric acid as a green chelating agent, exact extraction time and pH adjustment. Cu pharmaceutical and biological samples were eluted by acetonitrile: ammonium acetate (50 mM) with 0.5 mg/ml EDTA (30:70 v:v) as an isocratic mobile phase. EDTA reacted with Cu ions forming a Cu-EDTA coloured complex, separated through the C18 column and detected by UV at 310 nm. Results The developed method was specific with a short retention time of 4.95 min. It achieved high recovery from 100.3% to 109.9% in pharmaceutical samples and 96.8–105.7% in biological samples. The precision RSD percentage was less than two. The method was sensitive by achieving low detection limits (DL) and quantification limits (QL). Conclusion The validated method was efficient and economical for detecting Cu and CuNPs by readily available chemicals as EDTA and Citric acid with C18 column, which present the best results on RP-HPLC.

ZnO@SiO2/rGO core/shell nanocomposite: A superior sensitive, selective and reproducible performance for 1-propanol gas sensor at room temperature

In this research, the Staudenmaier method adopted to synthesize the reduced graphene oxide to be used in the ZnO@SiO2/rGO nanocomposite preparation by sol-gel assisted hydrothermal method. SEM images showed the formation of graphene oxide layers with a thickness of about 41 ± 1 nm as well as the formation of spherical ZnO@SiO2 nanoparticles with an average diameter of 32 ± 1 nm on graphene plates. The formation of expected elements in the fabricated nanocomposite, confirmed by the EDS analysis. XRD patterns showed that rGO and ZnO were crystalline and SiO2 was non-crystalline. The FT-IR spectrum of the desired microstructure and the TEM image confirmed the core/shell structure. The application of this nanocomposite as a gas sensor was evaluated. According to the measurements done at the ambient conditions (RH 45%, 29 °C), the sensor sensitivity to 300 ppm of the ethanol, methanol and 1-propanol, were 131.7, 21.8 and 156.8 units, respectively. Although the logarithm of the sensitivity linearly depends on the concentration of the samples in the range of 150–450 ppm, but the maximum R2 of 0.9478 indicates the ability of this sensor to quantitatively measure 1-propanol. The RSD percentage less than five for all samples indicates good reproducibility of the sensor response. Ten months investigation revealed that the appropriate time for repetitive responses of synthesized sensor is about 8 months. The response and recovery times were measured as improved sensor properties. The results showed that the synthesized sensor can be used as a quantitative and qualitative measurement of 1-propanol. Finally the sensing mechanism was discussed based on electronic transmissions.

Analytical method development and validation for the estimation of Furosemide an anti-diuretic in Furosemide injection diluted with normal saline in presence of impurities by RP-HPLC

This study was aimed to establish a simple, accurate, precise, robust and rapid reverse phase high performance liquid chromatographic method for the estimation of Furosemide in Furosemide injection diluted with normal saline and it was validated as per the parameters mentioned in the ICH guidelines such as system suitability, linearity, accuracy, precision, specificity, ruggedness and robustness and solution stability. The optimized chromatographic HPLC analysis was performed on Waters e2695 system equipped with Inertsil ODS-3V C18 column (250 cm x 150 mm; 5 um particle size), with a mixture of 1% glacial acetic acid and acetonitrile in the ratio of 50%:50% v/v as the mobile phase, at the flow rate of 1.0 mL/min. The detection was performed at the wavelength of 272 nm and the retention time of Furosemide was found to be 7.03 min. The calibration plot gave linear relationship over the concentration range of 10-120 ug/mL with correlation coefficient of r2 = 0.9998. The percentage purity of Furosemide in the given formulation was found to be 103.56 +/- 0.6546. The amount of Furosemide in the given formulation for intraday and interday was found to be 102.45 +/- 0.2291 and 102.67 +/- 0.4041, respectively. The accuracy of the proposed method was determined by recovery studies and was found to be in the range of 100.14% to 101.01%. This indicates that there is no inteference was observed due to excipients used in formulation. The percentage of RSD was found to be less than 2 for all the parameters. All the impurities peak were separated well and no inteference were found with the retention time of Furosemide. The results of robustness, ruggedness and solution stability were found to be within the acceptance limit. Hence, the developed method was found to be simple, linear, accurate, precise, robust, rapid method for the analysis of Furosemide in Furosemide injection diluted with normal saline. In addition, the main feature of the developed method is lower run time with less solvent consumption.

Synthesis of three-dimensional nickel ferrite nanospheres decorated activated graphite nanoplatelets for electrochemical detection of vortioxetine with pharmacokinetic insights in human volunteers.

An innovative electrochemical nanoprobe was developed for determination of vortioxetine (VORT), a serotonergic antidepressant drug, for the first time. The fabrication of thenanoprobe isbased on decoration of aglassy carbon electrode with three-dimensional nickel ferrite nanospheres modified activated graphite nanoplatelets (3D NiFe2O4 NS/AGNP/GCE). The morphological characterization of the nanoprobe was carried out via scanning electron microscope (SEM), transmission electron microscope (TEM), Fourier transform infrared spectroscopy (FT-IR), Raman spectroscopy, energy dispersive X-ray spectroscopy (EDS), N2-adsorption-desorption isotherm, and powder X-ray spectroscopy (PXRD). In addition, the electrochemical behavior of the nanoprobe was described usingcyclic voltammetry (CV), differential pulse voltammetry(DPV), and electrochemical impedance spectroscopy (EIS). A well-defined and irreversible peak at 0.82V was seen at the surface of 3D NiFe2O4 NS/AGNP/GCE. The proposed nanoprobe exhibited outstanding electro-catalytic activity towards VORT oxidation. Under the optimized conditions, the anodic oxidation currents were linearly proportional to VORT concentration at the working range 1.8-90nM with aLOD of 0.55nM. The nanoprobe was used to determine VORT in pharmaceutical tablets and human plasma samples. Satisfactory recoveries and RSD percentages were obtained in the range 103.8-107.7% (RSD% = 2.7-3.1%) and 101.4-105.3% (RSD % = 2.8-3.4%) for tablets and plasma samples, respectively. Moreover, the method was used to monitor VORT during apharmacokinetic study in human volunteers with satisfactory results. The 3D NiFe2O4 NS/AGNP/GCE shows excellent sensitivity, reproducibility, and selectivity towards VORT detection. The proposed electrode could be utilized as simple, rapid, and inexpensive sensing tool for routine analysis and during pharmacokinetic/pharmacodynamic investigations. Graphical abstract.

Monitoring of toxic heavy metals contamination in commonly used Chinese materia medica

Monitoring of toxic heavy metals (THMs) contamination, including lead (Pb), arsenic (As), cadmium (Cd), and mercury (Hg), for the quality control in Chinese materia medica (CMM) is critical for ensuring safe medication use in the pharmaceutical industry. A validated inductively coupled plasma–mass spectrometry method was used to determine THMs content in 1887 samples for 27 selected types of commonly used CMM. The correlation coefficient of the calibration curves for four THMs was higher than 0.995, indicating that the linearity is fine. The recovery rate was ranged in 82.6–105.4% for four THMs. The percentage of RSD in inter-day and intra-day precision test for four THMs was all lower than 10%. The limit of quantitation in test solution for Pb, As, Cd and Hg was 0.212, 0.500, 0.038, 0.044 μg/L, indicating that this validated ICP-MS method exhibited excellent sensitivity. Among these THMs, Pb and Cd are the most abundant contaminants in 27 selected types of CMM. In diverse permissible limits (PL) established by different countries/organizations, Cinnamomi ramulus and Eucommiae cortex usually exceeded the PL of 0.3 μg/g for Cd and occasionally exceeded the PL of 5.0 μg/g for Pb. Chuanxiong rhizome seldom exceeded the PL of 1.0 μg/g for Cd. Eucommiae cortex, Raphani semen, Atractylodis macrocephalae rhizoma and Bupleuri radix occasionally exceeded the PL of 0.3 μg/g for Cd. In conclusion, we hope to raise awareness of THMs contamination in commonly used CMM that affects safe medication use among farmers, manufacturer, and consumers.

Validated stability Spectrophotometric process for estimation vancomycin antibiotic degradation behavior in pharmaceutical kinds

Objective: To estimate the dissolution behavior of the antibiotic vancomycin hydrochloride in pharmaceutical formulations, a novel, quick as well as innovative stabilization implying spectrophotometric process has been created and certified. Using the spectrophotometric process to calculate the constant acid dissociation (Ka). Material and methods: The process focused on the observed drug oxidation by a documented excess of Ceric ammonium nitrate in hydrochloride acid solution as well as corresponding identification of unreacted oxidant by combining it with methylene blue respectively. The oxidant reacted correlates to the substance of the compound. As well as wave length absorbance calculation 588 nm. This approach follows Beer-Lambert plot regression showed remarkable concentration range 1-50 ppm associations. It was a coefficient of correlation of 0.9982. Calculated the limits of molar absorptivity 6.9117× 104 (L . mol-1. cm-1) , sandal sensitivity 0.02 µg. cm-2, identification 0.410 ppm, as well as quantification 0.731 ppm. The method's precision and accuracy was established and checked. Results: The stoichiometric proportions were analyzed for the aforementioned product. This measured the growing conditions of reaction as well as other analytical variables. The technique has decent repeatability with little than two percent relative standard deviation (RSD percentage). Conclusion: The impact of the material typically often used in such medications as excipients was examined. The suggested technique have been implemented in pharmaceutical products to assess such drugs. The findings showed that the technique is as reliable and repeatable as the approved technique.

Validation of forced degradation and stability indicating studies of Tamoxifen in nanoformulation using spectroscopic technique

The ultimate goal was to establish a simple, precise, reliable and stable UV method to estimate Tamoxifen in bulk and nanoformulations i.e. NLCs and SLNs. The optimal conditions for the drug evaluation have been identified. Tamoxifen has been subject to force degradation in various conditions. The λmax of Tamoxifen citrate in methanol was found to be 278 nm. The approach demonstrated high accuracy over the range of 2–20 μg/ml with a coefficient of correlation value of 0.999 with linearity curve. The limit of quantification and detection were found to be 1.871 and 0.617 μg/ml, respectively. The method’s accuracy was checked and found to be within the range of 101–104%. The lower RSD percentage values are suggestive of the method’s reliability and reproducibility. The reliability of the system has been evaluated as intraday and interday changes. Ruggedness was studied with the help of two researchers and in the two different laboratories. The sample solution was stable at low temperature. According to degradation studies, drug is highly degraded via oxidative stress. Entrapment efficiency of tamoxifen was found to be higher in NLCs (87.3%) as compared to SLNs (81.2%). The above methodology was a rapid tool for regular quality control testing of Tamoxifen in the bulk and nanoformulations.

A Simple Method for the Screening and Measurement of Phenols in Dendrobium chrysotoxum by a Miniature Mass Detector Using a Matrix Solid-Phase Dispersion Method.

The present study aims at building a miniature mass method for the simultaneous determination of 12 phenols including the subtypes of bibenzyl, phenanthrene, and fluorenone, which was used to evaluate the quality of Dendrobium chrysotoxum. Through the full scan mode, new compounds were elucidated. The new compounds were quantified by carrying out the analysis of the ratio of the standard solution areas to new compound areas versus analyte concentration. The limit of detection (LOD) and limit of quantification (LOQ) for phenols were 0.5 µg/mL–1 µg/mL and 1 µg/mL–2 µg/mL, respectively. Average recoveries of phenols were ranged from 83.2% to 97.5%. Reproducibility represented by the RSD percentage was from 2.3% to 8.7%. The average content of the four analytes, erianin, chrysotobibenzyl, confusarin, and moscatilin, were more than 200 mg/kg, and the content of bibenzyl compounds was found to be the highest in Dendrobium chrysotoxum. Among these bibenzyl compounds, erianin was determined as the typical chemical marker from Dendrobium chrysotoxum. The newly established UPLC with a miniature mass detector method was found to be an appropriate tool for the quality assessment of Dendrobium chrysotoxum.

Quantification of Trace Elements in Different Dokha and Shisha Tobacco Products using EDXRF.

The present study aims to quantify trace metals in different dokha (medwakh) and shisha tobacco products available in local markets. Recent research has shown that these products have higher amounts of nicotine and tar compared to various other tobacco products. No specific data are available on the concentration of trace elements in dokha (medwakh) and shisha tobacco products in the Middle East and North Africa (MENA) region. Harmful health effects due to the toxicity of these elements in tobacco and its smoke have not been adequately emphasized. Concentrations of trace elements were extensively studied using HORIBA XGT-7200 EDXRF fluorescence absorption spectroscopy. The mean concentrations of aluminum, calcium, chromium, copper, iron, magnesium, manganese, nickel, potassium, strontium and zinc in 13 dokha products in μg/g were 406.92 ± 41.72, 14703.27 ± 271.73, 11.73 ± 2.12, 25.58 ± 2.63, 753.85 ± 14.87, 5306.54 ± 134.94, 82.31 ± 4.55, 25.58 ± 2.50, 2212.12 ± 39.04, 816.92 ± 15.26 and 35.96 ± 2.63, respectively; and those in the three shisha products in μg/g were 244.83 ± 25.11, 8235.77 ± 144.51, 3.40 ± 0.38, 22.77 ± 4.50, 569.13 ± 10.22, 2096.20 ± 130.69, 72.13 ± 7.13, 27.67 ± 5.31, 4467.50 ± 168.06, 320.20 ± 6.03 and 36.40 ± 3.57, respectively. In our study, the quantified trace metal concentrations in dokha and shisha tobacco using the EDXRF method were ten times higher than the LODs. The percentage of RSD was <10%, validating the precision of the method. Tobacco smoking is a major source of consumption of toxic elements, not only in the smoker but also in non-smokers through passive smoking. In dokha (medwakh) and shisha tobacco products, compared with cigarettes, Ni levels were significantly higher, Cr, Cu and Zn levels were higher, and Fe levels were similar, while Al and Mn levels were lower. The dokha and shisha tobacco products have no filters; many toxic metals can quickly enter the lungs and cause different pulmonary diseases and oral infections. Tobacco smoking causes lung and oral cancers, chronic obstructive pulmonary disease and cardiovascular diseases.

Zero valent Fe-reduced graphene oxide quantum dots as a novel magnetic dispersive solid phase microextraction sorbent for extraction of organophosphorus pesticides in real water and fruit juice samples prior to analysis by gas chromatography-mass spectrometry.

A selective and sensitive magnetic dispersive solid-phase microextraction (MDSPME) coupled with gas chromatography-mass spectrometry was developed for extraction and determination of organophosphorus pesticides (Sevin, Fenitrothion, Malathion, Parathion, and Diazinon) in fruit juice and real water samples. Zero valent Fe-reduced graphene oxide quantum dots (rGOQDs@ Fe) as a new and effective sorbent were prepared and applied for extraction of organophosphorus pesticides using MDSPME method. In order to study the performance of this new sorbent, the ability of rGOQDs@ Fe was compared with graphene oxide and magnetic graphene oxide nanocomposite by recovery experiments of the organophosphorus pesticides. Several affecting parameters in the microextraction procedure, including pH of donor phase, donor phase volume, stirring rate, extraction time, and desorption conditions such as the type and volume of solvents and desorption time were thoroughly investigated and optimized. Under the optimal conditions, the method showed a wide linear dynamic range with R-square between 0.9959 and 0.9991. The limit of detections, the intraday and interday relative standard deviations (n = 5) were less than 0.07 ngmL-1, 4.7, and 8.6%, respectively. The method was successfully applied for extraction and determination of organophosphorus pesticides in real water samples (well, river and tap water) and fruit juice samples (apple and grape juice). The obtained relative recoveries were in the range of 82.9%-113.2% with RSD percentages of less than 5.8% for all the real samples.

Method Development Challenges and Regulatory Expectation in Nifedipine

Aim: A novel and accurate high-throughput tandem mass spectroscopic method has been developed and validated for determination of nifedipine, a calcium-channel blocker. Materials &amp; methods: Nifedipine was detected on a triple quadruple tandem mass spectrometer by multiple reactions monitoring mode via ESI source. Results: The selective and sensitive method was linear in the concentration range of 0.501 to 360.100 ng/ml and reported no matrix effect. The percent accuracy of the method was found to be between 99.7 and 102.80%, while percentage of RSD was in range of 1.77 to 4.73%. Conclusion: Validated method was used for bioavailability studies under fasting and fed conditions.

VALIDASI METODE ANALISIS ASAM LEMAK TRANS DALAM MAKANAN BERDASARKAN AOCS OFFICIAL METHOD Ce 1h-05

Cardiovascular disease is related to the high consumption of trans fatty acid. This issue has driven SEAFAST IPB Laboratory to develop a trans fatty acid analysis method for gas chromatography based on AOCS Official Method Ce 1h-05. This research was aimed to validate the method via three steps: preparation step, procedure orientation test, and method validation . During instrument performance testing in the preparation step, linearity, limit of detection (LoD), limit of quantitation (LoQ), range, and precision parameters were validated for FAME 9t-C18:1 and C18:2 isomer mix ed standard solution. During the method validation step, specificity, precision and accuracy parameters were validated for 9t-C18:1 compound attached to food matrix, i.e. doughnut . The instrument validation result of 9t-C18:1 standard solution had fulfilled the criteria of linearity (r 2 =1, requirement r 2 > 0.990) within the range of 0.0020 to 0.1200 mg/mL; precision (RSD) 0.24%; LoD 0.0007 mg/mL and LoQ 0.0020 mg/mL. The instrument validation result for each isomer in C18:2 standard solution also met the criteria of linearity (r 2 = 0.9999, requirement r 2 > 0 . 990) with precision (RSD), LoD and LoQ respectively; 1) 9t,12t- C18:2 : 1 . 40%; 0 . 0033 mg/mL; 0.0100 mg/mL; 2) 9t,12c- C18:2 : 1.89%; 0.0015 mg/mL; 0.0045 mg/mL; 3) 9c,12t- C18:2 : 2.39%; 0 . 0015 mg/mL; 0 . 0044 mg/mL; 4) C18:2 cis: 3 . 39%; 0 . 0006 mg/mL; 0 . 0019 mg/mL. The validation result for 9t-C18:1 in 100 mg fat extract of doughnut suggested that the modified method is validated in term of specificity (Rs = 1 . 2), precision (RSD fatty acid content (mg/g) = 1.78%; RSD percentage of fatty acid content towards total fatty acid = 0.72%) and accuracy ( as percentage of recovery ) 80.54-94.25%.

Development and validation of a cyclodextrin-modified capillary electrophoresis method for the enantiomeric separation of vildagliptin enantiomers.

The enantiomers of vildagliptin, an orally available and selective dipeptidyl-peptidase-4 inhibitor used for the treatment of type II diabetes, have been separated by CD-modified CZE, using uncoated fused-silica capillary. After screening 13 negatively charged CD derivatives as potential chiral selectors, sulfobutyl-ether-α-CD (SBE-α-CD) was selected for the enantioseparation. For the optimization, a factorial analysis study was performed by orthogonal experimental design. Six experimental factors were chosen as variable parameters: temperature, applied voltage, chiral selector and BGE concentrations, pH, and the parameters of the hydrodynamic injection. The optimized system still was not considered final as the second peak (S-enantiomer) migrated too close to the EOF, resulting in a potential inaccuracy during the determination of the chiral impurity. To fine-tune the method "one factor at a time" variation approach was applied. The final method (applying 15°C capillary temperature, 40 mbar × 4 s hydrodynamic injection, 25 kV voltage in 75 mM acetate-Tris buffer [pH 4.75] containing 20 mM SBE-α-CD as chiral selector) was validated according to the ICH guideline. RSD percentage of the resolution value, migration times, and corrected peak areas were below 5% during testing repeatability and intermediate precision. LOD and LOQ values were found to be 2.5 and 7.5 μg/mL, respectively. The method is considered linear in the 7.5-180 μg/mL range for the R-enantiomer. The robustness of the method was justified using Plackett-Burmann statistical experimental design.

Separation of alogliptin enantiomers in cyclodextrin‐modified capillary electrophoresis: A validated method

The single enantiomer drug, alogliptin (Alo, Nesina®) is a novel, orally available and selective dipeptidyl peptidase-4 inhibitor used for the treatment of type II diabetes. Following its pKa determination by CE-pH titration, a validated chiral CE method has been developed to separate Alo enantiomers. Preliminary screening of the native CDs and their ten derivatives revealed that sulfopropylated-γ-CD, sulfopropylated-β-CD and sulfopropylated-γ-CD, sulfobutyl-ether-β-CD (SBE-β-CD) and sulfobutyl-ether-γ-CD enabled enantioresolution. Furthermore, cavity size dependent enantiomer migration order reversal was observed between γ- and β-CD derivatives. To improve enantioseparation, buffer composition and pH, CD concentration, applied voltage, temperature, and injection parameters were optimized for the Alo/ SBE-β-CD system, yielding a resolution of 8.34. RSD percentage of the resolution value, migration times, and corrected peak areas were below 3 and 5% during testing repeatability and intermediate precision. LOD and LOQ values were found to be 2 and 6 μg/mL, respectively, for each enantiomer. Calibration lines ranging from 6 to 250 μg/mL were constructed with r(2) > 0.9997. Robustness could be successfully verified by using the Plackett-Burman statistical experimental design. The optimized system containing 5mM SBE-β-CD in a 25mM acetate buffer at pH 4.75 was found promising to detect 0.1% distomer in the presence of the API.

Variability of microchip capillary electrophoresis with conductivity detection

Microfluidic CE with conductivity detection platforms could have an impact on the future development of smaller, faster and portable devices. However, for the purpose of reliable identification and quantification, there is a need to understand the degree of irreproducibility associated with the analytical technique. In this study, a protocol was developed to remove baseline drift problems sometimes observed in such devices. The protocol, which consisted of pre-conditioning steps prior to analysis, was used to further assess measurement variability from 24 individual microchips fabricated from six separate batches of glass substrate. Results show acceptable RSD percentage for retention time measurements but large variability in their corresponding peak areas (with some microchips having variability of ∼50%). Sources of variability were not related to substrate batch but possibly to a number of factors such as applied voltage fluctuations or variations in microchannel quality, for example surface roughness that will subsequently affect microchannel dimensions.

Analysis of synthetic cannabinoids in herbal blends by means of nano-liquid chromatography

In this study, a rapid and simultaneous separation of 12 synthetic cannabinoids and Δ9-tetrahydrocannabinol (Δ9-THC) in herbal blends was obtained by means of nano-liquid chromatography (nano-LC). The nano-LC experiments were performed in a 100μm i.d. capillary column packed with Cogent® bidentate C18 silica particles for 25.0cm. All compounds were resolved using an isocratic elution mode in less than 30min. A mobile phase containing ACN/MeOH/H2O/formic acid 69/5/25/1 (v/v/v/v) was employed for the chromatographic separation. The developed analytical method was validated in terms of precision, linearity, sensitivity and accuracy. Under optimal nano-LC–UV conditions, the resulting RSD percentages for intra-day and inter-day repeatability, related to retention time and peak area, were below 2.98 and 6.40%, respectively. Limits of detection and quantification were 0.2 and 0.5μg/mL, respectively, for all the studied compounds. Linearity was assessed in the concentration range of interest for all analytes with determination coefficients r2≥0.9975. The method was then applied to the determination of synthetic cannabinoids in herbal blends. Quantitative analyses of the cannabimimetic compounds in six products showed that there was a wide difference in the concentration of the studied compounds among different products. Further, the nano-LC system was coupled with a mass spectrometer measuring the MS and MS–MS spectra to unequivocally identify the cannabinoids present in smoking mixtures.

Development and validation of new RP-HPLC method for the determination of dexrazoxane

A new sensitive, precise, rapid and linear RP-HPLC method was developed and validated for the determination of dexrazoxane in formulations and human serum samples. Good chromatographic separation of dexrazoxane was achieved by using Kromasil C18 column. The system was operated at ambient temperature using a mobile phase consisting of methanol, 5% ortho phosphoric acid, 0.01M ammonium dihydrogen phosphate and tetrahydrofuran, pH 4.2 (10:40:30:20, v/v) isocratically at a flow rate of 1 ml/min. The method showed high sensitivity with good linearity (r2=0.9998) over the tested concentration range of 0.1 to 0.9 mg/ml. Detection was carried out at 272 nm and retention time was 7.005 min. The accuracy, formulation assay and percentage of RSD were 100.03, 97.48 and 0.03184, respectively with tailing factor (1.84). This method can be used for the routine quality control analysis.