Simultaneous determination of ofloxacin and flavoxate hydrochloride by first-and ratio first-derivative UV spectrophotometry

Two simple, precise, accurate and sensitive UV spectrophotometric methods were developed and validated for the simultaneous determination of ofloxacin (OFX) and flavoxate HCl (FLX) in bulk and pharmaceutical formulations. In one method, first-derivative absorption at 303.6?nm (for OFX at its zero crossing) and 329.8?nm, (for FLX at its zero crossing) was used for the determination of the drugs and the linearity range was found to be 0.5?C70???g?ml^?1 for FLX and 0.5?C30???g?ml^?1 for OFX. In the second method, the ratio derivative spectrophotometry method was developed making use of amplitude in the first derivative of the corresponding ratio spectra at 290?nm (maxima) and 254?nm (minima) to estimate OFX and FLX, respectively. Further, the linearity range was found to be 0.5?C25???g?ml^?1 for OFX and 0.5?C30???g?ml^?1 for FLX. In both the methods, correlation coefficient was found to be more than 0.999. Both methods were validated according to ICH guidelines by assessing the linearity, accuracy, precision, limit of quantification, limit of detection and selectivity. The results demonstrate that both methods are accurate, precise and reproducible (relative standard deviation <2), while being simple, cheap and less time-consuming, and hence can be suitably applied for the simultaneous estimation of OFX and FLX in pharmaceutical formulation and for dissolution studies.     

Development and Validation of Improved Reversed Phase-HPLC Method for Simultaneous Determination of Curcumin, Demethoxycurcumin and Bis-Demethoxycurcumin

Isocratic reversed phase high performance liquid chromatographic (HPLC) method using RP C18 column was developed for simultaneous determination of the curcuminoids. Mobile phase consisted of acetonitrile:0.1% trifluro-acetic acid (50:50) and flow rate was 1.5 mL min⁻¹ and elution was monitored at 420 nm. Validation in selected conditions showed that the chosen method is sensitive, selective, precise and reproducible with linear response of detector for the simultaneous determination of curcumin (C), demethoxycurcumin (DMC) and bis-demethoxycurcumin (BDMC). The limits of detection were 27.99, 31.91 and 21.81 ng mL⁻¹ for C, DMC and BDMC, respectively. Limits of quantitation for C, DMC and BDMC, were 84.84, 96.72 and 66.10 ng mL⁻¹, respectively. Linear range was form 100 to 600 ng mL⁻¹. The mean ± SD percent recoveries of curcuminoids were 99.87 ± 0.34, 100.09 ± 0.48 and 100.10 ± 0.60% of C, DMC and BDMC, respectively. Further, the method was used for quantitation of curcuminoids from turmeric rhizome.     

Single robust RP-HPLC analytical method for quantification of curcuminoids in commercial turmeric products,Ayurvedic medicines,and nanovesicular systems

A single robust reversed-phase high-performance liquid chromatography (RP-HPLC) method was developed and validated as per International Conference on Harmonization guidelines for the accurate quantification of curcuminoids in commercial turmeric products, Ayurvedic medicines, and nanovesicular systems. The proposed chromatographic method was found to be specific, linear (r²?≥?0.999), precise at intra- and inter-day levels (percentage relative standard deviation <2.0%), accurate (percentage recovery 99.14–102.29%), and robust. The limits of detection and quantification were found to be 7.40 and 24.70?ng?mL^?1 for curcumin, 9.24 and 30.80?ng?mL^?1 for demethoxycurcumin, and 6.48 and 21.61?ng?mL^?1 for bisdemethoxycurcumin, respectively. Among different commercial turmeric products and Ayurvedic medicines tested, the contents of curcumin (3.54?±?0.06–25.8?±?0.08?mg?g^?1), demethoxycurcumin (1.28?±?0.02–9.97?±?0.03?mg?g^?1), and bisdemethoxycurcumin (0.50?±?0.01–5.97?±?0.01?mg?g^?1) varied significantly. The developed method was effectively applied to the determination of encapsulation efficiency of curcuminoids (ranged between 84.33?±?3.50 and 96.59?±?2.53%) in the nanovesicular systems. In conclusion, the reported method is suitable for the analysis of curcuminoids in a wide variety of turmeric products and used for the quality control of products that contain curcuminoids.     

Validated TLC-Image Analysis Method for Simultaneous Quantification of Curcuminoids in Curcuma longa

A simple and rapid thin layer chromatographic (TLC)-image analysis method was developed for simultaneous quantification of three curcuminoids; curcumin (CUR), desmethoxycurcumin (DES) and bisdesmethoxycurcumin (BIS), in Curcuma longa (turmeric). Chromatographic separation of the curcuminoids was achieved on silica gel 60 F254 TLC plates, using chloroform–hexane–methanol (1:1:0.1, v/v/v) as the mobile phase. Image analysis of the scanned TLC plate was performed by Photoshop 7.0 to quantify the amount of each curcuminoid. The method was validated and found to be accurate, reliable and convenient for the analysis of CUR, DES and BIS in turmeric.

     

Simultaneous quantification of brexpiprazole and sertraline HCl in synthetic mixture by thin-layer chromatography method

According to the International Council for Harmonisation (ICH) Q2 (R1) guideline, a sensitive, precise, accurate and robust high-performance thin-layer chromatographic (HPTLC) method was developed and validated for the simultaneous quantification of a newer combination of brexpiprazole (BREX) and sertraline HCl (SERT) in bulk and synthetic mixture. Stationary phase selected was pre-coated silica gel aluminum plate 60 F_254, and n-propanol‒hexane‒toluene‒triethylamine (7:2:1:0.1, V/V) was used as developing mobile phase. An appreciable absorbance shows at 254 nm, therefore the common detection wavelength was selected for the simultaneous quantification of BREX and SERT. The method was validated for different parameters: linearity, precision, accuracy, robustness, limit of detection and limit of quantification as per ICH guideline. The correlation coefficients (r²) for BREX and SERT were found to be 0.9940 and 0.9911, respectively. The mean of percentage recoveries for BREX and SERT were found to be 99.40–102.10% and 99.52–101.05%, respectively. The proposed HPTLC method has potential application for the quantification of BREX and SERT simultaneously in bulk and synthetic mixture both qualitatively and quantitatively.

     

Simultaneous Determination of Diclofenac Sodium and Rabeprazole Sodium in Bulk and Pharmaceutical Dosage Form by LC

A simple, selective, rapid, precise and accurate reverse phase high pressure liquid chromatographic method has been developed for the simultaneous estimation of diclofenac sodium and rabeprazole sodium from pharmaceutical formulations. The method was developed using a HiQ SiL C18 (250 mm × 4.6 mm i.d.) column with a mobile phase consisting of methanol:water, (80:20 v/v), at a flow rate of 1.25 mL min⁻¹. Detection was carried out at 284 nm. Indapamide was used as an internal standard. The developed method was validated for linearity, accuracy, precision, limit of detection and limit of quantitation. The proposed method can be used for the estimation of these drugs in combined dosage forms.

     

NP-HPLC method for determining phytonadione and its impurities

A normal-phase high-performance liquid chromatography method has been developed to separate vitamin cis-phytonadione (cis-K1), trans-phytonadione (trans-K1), trans-epoxyphytonadione (trans-EK1), menadione (K3), cyclo-menadione (CK3), hydroperoxy-phytonadione (K1OOH), and other impurities on a Zorbax RX-SIL column, characterized by very pure porous silica, low acidity, and low metal content. A dual-mode gradient elution was applied involving simultaneous changes in flow rate and mobile-phase composition. The present method was sensitive enough to detect trans-EK1 (limit of detection, LOD: 1.8?ng), K3 (LOD: 0.6?ng), CK3 (LOD: 1.2?ng), and K1OOH (LOD: 2.4?ng). A linear relationship between peak area and concentration was found for four compounds with correlation coefficient r exceeding 0.9994. The impurities (trans-EK1, K3, and K1OOH) were measured accurately (recovery rate 80–120%) and precisely (relative standard deviation less than 2%). Preparing samples under yellow light (≥520?nm), the K1OOH in the three commercial batches of K1 was no higher than 0.10% (w/w) and was measured with a reproducibility of 3.1% and with an intermediate precision of 15.8%. After validation, the developed method was applied for analyzing the impurities occurring in the commercial samples of synthetic K1 and proved to be suitable for routine quality control.     

高效液相色谱-串联质谱法分析姜黄中微量的姜黄素类化合物

建立了同时检测中药姜黄中3种微量的姜黄素类化合物的高效液相色谱-电喷雾串联质谱分析方法。姜黄根茎经乙醇超声提取后,无需其他处理可直接进样分析。以Microsorb C18色谱柱(250 mm×4.6 mm,5 μm)分离,乙腈和0.1%甲酸水梯度洗脱,在多反应监测模式(MRM)下对目标成分进行定性分析。利用质谱碎裂规律,分别对每个目标成分同时监测8个母离子/特征子离子对的反应过程,首次从姜黄中发现了3个微量的姜黄素类化合物成分。一次性完成了目标成分的同时定性,方法的检出限为0.2 μg/L。结果表明,该方法具有简便、快速、准确、灵敏度高的优点,适用于中药复杂体系中姜黄素类化合物的分析检测。     

Simultaneous estimation of genistein and daidzein in Pueraria tuberosa (Willd.) DC by validated high-performance thin-layer chromatography (HPTLC) densitometry method

The present study was performed to estimate the concentration of genistein and daidzein in ethanol extract of tubers of Pueraria tuberosa (Indian kudzu or Vidarikanda) and its various fractions (n-hexane, ethyl acetate, n-butanol, and aqueous) by high-performance thin-layer chromatography (HPTLC). The separation of bioactive compounds was performed using mobile phase, toluene:ethyl acetate:acetone:formic acid (20.0:4.0:2.0:1.0) and detected at wavelength 269?nm. The method was validated for linearity, accuracy, precision, limit of detection (LOD), limit of quantification (LOQ), etc. by International Conference on Harmonization guidelines. The calibration range was found to be 100–600?ng/band for both the bioactive compounds. Daidzein was separated with an R_f value of 0.39?±?0.02 and genistein with an R_f value of 0.54?±?0.02. Average recovery was 99.96 and 99.90% for genistein and daidzein, respectively. The LOD and LOQ were 14.786 and 44.805?ng, respectively, for genistein, and 9.607 and 29.114?ng, respectively, for daidzein. Both the phytoconstituents were found in ethanol extract and its ethyl acetate fraction only. The developed HPTLC method was simple, precise, robust, specific, rapid, and cost effective and could be used for quality control analysis and quantification of genistein and daidzein in different herbal formulations containing the plant species.     

Simultaneous densitometric analysis of amlodipine,hydrochlorothiazide, lisinopril,and valsartan by HPTLC in pharmaceutical formulations and human plasma

A simple, accurate, and precise high-performance thin layer chromatographic (HPTLC) method has been developed and validated for the simultaneous quantification of antihypertensive drugs, amlodipine (AML), hydrochlorothiazide (HCTZ), lisinopril (LIS), and valsartan (VAL) in their pharmaceutical formulations and human plasma. Separation of the drugs was performed on aluminum-backed layer of silica gel 60?F₂₅₄ using a mixture of methanol–dichloromethane–glacial acetic acid (9.0:1.0:0.1, v/v/v) as the mobile phase. Densitometric determination of the separated spots was done at 215?nm. The retention factors (R_f) obtained under the optimized conditions were 0.56, 0.75, 0.29, and 0.67 for AML, HCTZ, LIS, and VAL, respectively. Linearity of the method was established in the range of 200–1,500?ng/band for AML, 300–1,500?ng/band for HCTZ, 400–2,000?ng/band for LIS, and 1,000–7,000?ng/band for VAL. The limit of detection/limit of quantitation of the method found were 54.21/164.28, 77.27/234.15, 83.45/252.87, and 156.48/474.19?ng/band for AML, HCTZ, LIS, and VAL, respectively. To determine the drugs in spiked plasma samples, solid phase extraction was performed, which provided highly consistent and quantitative recovery for all four drugs. The method was satisfactorily applied for the analysis of different tablet formulations and proved to be specific and accurate for the quality control of these drugs.     

Simultaneous quantification of 11 isoquinoline alkaloids in Corydalis impatiens (Pall.) Fisch by HPLC

Isoquinoline alkaloids are the primary active ingredients of Corydalis, but an analytical method for quality assessment of the active ingredients in Corydalis impatiens (Pall). Fisch has not been reported. A new, simple, and multiple‐component quantification method was developed for the simultaneous quantification of 11 isoquinoline alkaloids including capnoidine, chelianthifoline, bicuculline, protopine, isoapocavidine, apocavidine, cavidine, tetrahydroepiberberine, ochotensimine, tetrahydrocoptisine, and tetrahydrocorysamine in C. impatiens. Separation of the isoquinoline alkaloids was performed on a RP C₁₈ column (150 × 4.6 mm, 5 μm) with potassium dihydrogen phosphate buffer (pH 2.5, adjusted by phosphoric acid)/acetonitrile (53:47, v/v) containing 0.3% sodium dodecyl sulfonate. The flow rate and detection wavelength were set at 1 mL/min and 295 nm, respectively. Full validation of the assay was carried out including linearity, precision, accuracy, stability, LOD, and limit of quantitation. All calibration curves showed a good linear relationship (r > 0.999) in test range. The results demonstrated that the developed method was reliable, rapid, and specific. Six batches of C. impatiens samples from different sources were determined using the established method. The contents of alkaloids ranged from 11.68 to 351.83 μg/g. This method can be applied for quality evaluation and control of C. impatiens. Eleven isoquinoline alkaloids were first reported on simultaneous determination with HPLC.     

Simultaneous determination of iodate and periodate by kinetic spectrophotometric method using principal component artificial neural network

A kinetic spectrophotometric method for the simultaneous determination of iodate and periodate in mixtures was proposed. The method was based on the reaction of periodate and iodate with pyrogallol red in sulfuric acid media. The reaction was monitored spectrophotometrically by measuring the decrease in absorbance of pyrogallol red at 470 nm. Kinetic data collected at 470 nm were processed by principle component artificial neural network (PC-ANN) method. The constructed model was able to predict the concentration of two species in the range of 0.1?C15.0 and 0.1?C17.0 ??g/mL for iodate and periodate, respectively. The proposed method was applied to the simultaneous determination of iodate and periodate in several real samples with satisfactory results.     

Determination of Heraclenin and Heraclenol in Heracleum candicans D.C. by TLC

A simple TLC method has been developed for the simultaneous determination of heraclenin and heraclenol in the roots of Heracleum candicans D.C. The analytes were separated on silica gel F₂₅₄ plates with toluene:ethyl acetate (7:3) and scanned using densitometry at 366 nm. The method was validated in terms of precision, repeatability and accuracy. The linear range for heraclenin was found to be 4 - 10 μg per spot with correlation coefficient of 0.997 while for heraclenol it was 1–5 μg per spot with a correlation coefficient of 0.985. The two compounds were quantified in different samples of H. candicans and were found to be present in the range of 1.02 – 1.36% and 0.29 – 0.43% w/w. The method was found to be very simple, accurate, precise and economical and can be used for routine quality control.     

A sensitive chromatographic determination of hydrazines by naphthalene-2,3-dialdehyde derivatization

A new high-performance liquid chromatography (HPLC) method for the sensitive simultaneous determination of hydrazine (Hy), monomethylhydrazine (MMH) and 1,1-dimethylhydrazine (UDMH) based upon the derivatization of hydrazines with naphthalene-2,3-dialdehyde and the separation of the derivatives on Zorbax Eclipse AAA column in a single chromatographic run under acidic conditions (pH 2.4) was developed. Hydrazine and monomethylhydrazine derivatives were found to be strongly fluorescent at λ_ex?=?273?nm, λ_em?=?500?nm. It was shown that UDMH derivative can be detected as non-fluorescent hydrazone at 290?nm by UV-detection. Limits of detection were 0.05?µg?·?L^?1 for Hy and MMH, and 1?µg?·?L^?1 for UDMH for the injection volume of 100?µL. The method was validated for water sample analysis. It proved to be selective, accurate and precise with the supplementary advantage of the simple and rapid sample preparation.     

同步-偏振-导数荧光法同时测定三种苯二酚异构体的研究

苯二酚的三种异构体, 由于其吸收光谱和荧光光谱均重叠严重, 不能用常规分光光度法和荧光法进行同时测定. 而以λ＝0 nm进行同步扫描时, 在350～500 nm之间具有相似的荧光光谱特征, 其荧光强度有良好的加和性, 可以对三者进行总量测定. 研究还发现三种苯二酚异构体与Cu^2＋和异烟肼形成1∶1∶2的配位合物时, 用Δλ＝30 nm进行同步扫描并采用偏振和一阶导数法, 间苯二酚的导数荧光峰位于260 nm处, 对苯二酚的导数荧光峰位于320 nm处, 两者能很好分开, 而此时邻苯二酚荧光峰消失, 因此可在三者的混合物中分别测定间、对苯二酚, 然后再从总量中减去间、对苯二酚的含量, 从而测到邻苯二酚的浓度, 因此本工作通过上述方法可对三种苯二酚异构体进行同时测定. 其线性范围均在3×10^－6～5×10^－4 mol/L之内, 间苯二酚和对苯二酚的检出限分别是2.5×10^－7 mol/L和3.1×10^－7 mol/L; 其混和物总量的检出限是4.5×10^－7 mol/L, RSD均在5%以下. 该方法简便快速, 有良好的准确性和重复性, 用于环境水样中三种苯二酚的同时测定, 获得满意结果.     

Determination of atorvastatin in human plasma by magnetic solid-phase extraction combined with HPLC and application to a pharmacokinetic study

A simple and sensitive analytical procedure by solid-phase extraction method combined with high-performance liquid chromatography and using of graphene–magnetite nanomaterials as sorbent has been developed for the determination of atorvastatin in human plasma. A magnetic solid-phase extraction method as a simple, fast, and efficient extraction technique has been used for sample preparation. A solid nanocomposite material, graphene nanosheets decorated with magnetite nanoparticles, was used as a magnetic adsorbent and the adsorption process was optimized in this study. RP C18 column was used with mobile phase composed of acetonitrile–10?mM orthophosphoric acid by isocratic elution with the flow rate of 1?mL?min^?1. Fluorimetric detection was used by the excitation wavelength at 282?nm and the emission wavelength at 400?nm. It was found that the calibration curve was linear in the 30–150?ng?mL^?1. Limit of detection and limit of quantitation values were found to be 10 and 30?ng?mL^?1, respectively. The intra-day and inter-day relative standard deviation values were less than 5.27%. It has been concluded that the new developed method provides fast, simple, cost reduced, and sensitive assay for atorvastatin determination in human plasma. This method is also applied to a pharmacokinetic study.     

Development and validation of a simple HPTLC method for the determination of new hepatitis C subtype 4 antiviral agents in their tablet dosage form

A new, simple, precise, accurate and selective high-performance thin-layer chromatographic (HPTLC) method has been developed and validated for the simultaneous determination of ledipasvir and sofosbuvir in their tablet dosage form. Chromatographic separation was carried out on Merck TLC aluminum sheets of silica gel 60 F₂₅₄ using ethyl acetate:hexane:methanol in the ratio of 8:1.25:0.75 (% v/v) as the mobile phase followed by densitometric measurement at 256 nm. The method was validated in terms of linearity, accuracy, precision, limit of detection, limit of quantification and specificity in accordance with the International Conference on Harmonization (ICH) guidelines. The calibration curve was found to be linear between 60 to 1980 and 45 to 3600 ng/band for ledipasvir and sofosbuvir, respectively, with significantly high value of regression coefficient (r² > 0.9999) with linear and homoscedastic residuals. The limits of detection and quantification were found to be 16.5 and 50 ng/band, respectively, for ledipasvir and 13 and 39.5 ng/band, respectively, for sofosbuvir. Comparative study was performed between the developed HPTLC method and the reported high-performance liquid chromatography (HPLC) method. The quantitative results of the two analytical methods did not show statistically significant difference, whereas the developed HPTLC method is both time- and cost-effective.

     

Concurrent quantification of oleanolic acid, β-sitosterol and lupeol by a validated high-performance thin-layer chromatography method in Urginea indica Kunth bulb

A validated high-performance thin-layer chromatography (HPTLC) method was developed for the simultaneous quantification of oleanolic acid, β-sitosterol and lupeol in the bulb of Urginea indica Kunth. Separation of metabolites was done in mobile phase using toluene‒ethyl acetate‒methanol‒acetone (7:2:0.2:0.2, V/V) and quantification was done after derivatization by dipping in aninsaldehyde‒sulphuric acid; densitometric scan was performed at 530 nm. The proposed method for quantification was linearly calibrated in the range of 200‒1000 ng/spot for oleanolic acid and β-sitosterol; 100‒500 ng/spot for lupeol, and it was found specific and repeatable. The R_F values were found at 0.44 ± 0.03, 0.55 ± 0.05 and 0.68 ± 0.08, limit of detection and limit of quantification were 1.045, 0.524, 0.525 µg/spot and 3.167, 1.588, 1.592 µg/spot for oleanolic acid, β-sitosterol and lupeol, respectively. Precision and recovery study for sample and standards were within the limit of the International Council for Harmonization guidelines. Oleanolic acid, β-sitosterol and lupeol were found to be 0.113%, 0.105% and 0.036%, respectively, in methanolic extract of plant on dry weight basis. This study will help in checking routine quality control of herbal drugs as well as herbal formulations containing U. indica.

     

Determination of curcuminoids in substances and dosage forms by cyclodextrin-mediated capillary electrophoresis with diode array detection

The present work illustrates the potential of the capillary zone electrophoresis (CZE) separation technique coupled with the on-capillary diode array detector (DAD) for highly reliable determination of curcuminoids (curcumin, CUR, demethoxycurcumin, DCUR, and bisdemethoxycurcumin, BCUR) in substances (commercially available plant extract) and pharmaceutical preparation (commercial pharmaceutical capsules) with minimal sample preparation; (2-hydroxypropyl)-β-cyclodextrin (HP-β-CD) was chosen for an anionic separation of CUR and its structural analogues (DCUR and BCUR) as an appropriate complexing agent (i) providing complete resolution of the curcuminoids and (ii) reducing adsorption of these hydrophobic analytes onto the capillary wall. DAD detection was utilised for characterisation of the composition of the separated zones via differences in the corresponding UV-VIS spectra (scanned at interval of 200–800 nm). Reference and real spectra of the analytes demonstrated that the proposed separation method was sufficiently selective to produce well-separated (i.e. spectrally homogeneous) analyte zones with no interfering compounds present. Successful validation and application of the CZE-DAD method proposed here suggest its routine use in highly effective and reliable analysis of curcuminoids in pharmaceutical samples.     

Simultaneous determination of six perylenequinones in Shiraia sp. Slf14 by HPLC

The aim of the study was to develop a rapid and sensitive analytical method for simultaneous determination of the hypocrellin A, hypocrellin B, hypocrellin C, elsinochrome A, elsinochrome B, and elsinochrome C content in the Huperzia serrata endophytic fungus Shiraia sp. Slf14. Separation was performed by high-performance liquid chromatography (HPLC) with an YMC-Triart C18 column (4.6?mm?×?250?mm, 5?µm), elution with acetonitrile and triple-distilled water (volume ratio 70:30) as the mobile phase, a detection wavelength of 460?nm, and a flow rate of 1.0?mL/min. All six pigments were successfully determined with good linear correlations and a precision relative standard deviation <2.3%. The methodology was applied to simultaneously measure the concentration of perylenequinones and their derivatives during submerged fermentation and proved adequate for analysis of the biosynthesis of perylenequinones.