Validated Stability-Indicating RP-HPLC Method for the Simultaneous Determination of Azelnidipine and Olmesartan in Their Combined Dosage Form

A simple, rapid, and highly selective RP-HPLC method was developed for the simultaneous determination of Azelnidipine (AZL) and Olmesartan (OLM) drug substances in the fixed dosage strength of 16 mg and 20 mg, respectively. Effective chromatographic separation was achieved using a Hypersil GOLD C18 column (150 mm × 4.6 mm internal diameter, 5 µm particle size) with a mobile phase composed of methanol, acetonitrile, and water in the ratio of 40:40:20 (by volume). The mobile phase was pumped using a gradient HPLC system at a flow rate of 0.5 mL/min, and quantification of the analytes was based on measuring their peak areas at 260 nm. The retention times for Azelnidipine and Olmesartan were about 8.56 and 3.04 min, respectively. The reliability and analytical performance of the proposed HPLC procedure were statistically validated with respect to system suitability, linearity, ranges, precision, accuracy, specificity, robustness, detection, and quantification limits. Calibration curves were linear in the ranges of 2–48 μg/mL for Azelnidipine and 2.5–60 μg/mL for Olmesartan with correlation coefficients >0.990. The proposed method proved to be selective and stability-indicating by the resolution of the two analytes from the forced degradation (hydrolysis, oxidation, and photolysis) products. The validated HPLC method was successfully applied to the analysis of AZL and OLM in their combined dosage form.     

Validated Stability-Indicating HPLC-DAD Method for the Simultaneous Determination of Diclofenac Sodium and Diflunisal in Their Combined Dosage Form

A simple, rapid, and highly selective HPLC-DAD method was developed for the simultaneous determination of diclofenac sodium (DIC) and diflunisal (DIF) in pure form and in their combined formulation. Effective chromatographic separation was achieved using a Zorbax SB-C8 (4.6×250 mm, 5 μm particle size) column with a mobile phase composed of 0.05 M phosphoric acid, acetonitrile, and methanol in the ratio of 40:48:12 (by volume). The mobile phase was pumped isocratically at a flow rate of 1 mL/min, and quantification of the analytes was based on measuring their peak areas at 228 nm. The retention times for diflunisal and diclofenac were about 7.9 and 9.5 min, respectively. The reliability and analytical performance of the proposed HPLC procedure were statistically validated with respect to system suitability, linearity, ranges, precision, accuracy, specificity, robustness, detection, and quantification limits. Calibration curves were linear in the ranges of 5–100 μg/mL for both drugs with correlation coefficients >0.9998. The proposed method proved to be selective and stability-indicating by the resolution of the two analytes from four of their related substances and potential impurities as well as from forced-degradation (hydrolysis, oxidation, photolysis, and dry heat) products. The validated HPLC method was successfully applied to the analysis of DIC and DIF in their combined dosage form (suppositories). The proposed method made use of the diode array detector (DAD) as a tool for peak identity and purity confirmation.     

Development and Validation of a Stability-Indicating RP-HPLC Method for the Simultaneous Determination of Phenoxyethanol,Methylparaben, Propylparaben,Mometasone Furoate,and Tazarotene in Topical Pharmaceutical Dosage Formulation

A stability-indicating RP-HPLC method has been developed and validated for the simultaneous determination of phenoxyethanol (PE), methylparaben (MP), propylparaben (PP), mometasone furoate (MF), and tazarotene (TA) in topical pharmaceutical dosage formulation. The desired chromatographic separation was achieved on the Waters X-Bridge™ C18 (50×4.6mm, 3.5μ) column using gradient elution at 256 nm detection wavelength. The optimized mobile phase consisted of 0.1%v/v orthophosphoric acid in water as solvent-A and acetonitrile as solvent-B. The method showed linearity over the range of 5.88–61.76 μg/mL, 0.18–62.36 μg/mL, 0.17–6.26 μg/mL, 0.47–31.22 μg/mL, and 0.44–30.45 μg/mL for PE, MP, PP, MF, and TA, respectively. The recovery for all of the components was in the range of 98–102%. The stability-indicating capability of the developed method was established by analysing the forced degradation samples, in which the spectral purity of PE, MP, PP, MF, and TA along with the separation of degradation products from the analyte peaks was achieved. The proposed method was successfully applied for the quantitative determination of PE, MP, PP, MF, and TA in a cream sample.     

Fast separation and quantification of three antiglaucoma drugs by high-performance liquid chromatography UV detection

In this study, a simple and accurate high-performance liquid chromatography method was developed and validated for fast separation of three anti-glaucoma drugs: timolol maleate (TM), brimonidine tartrate (BM), and latanoprost (LP). Separation of the three drugs was achieved in < 6 minutes using a BDS Hypersil phenyl column and a mobile phase consisting of acetonitrile: 25mM phosphate buffer, pH 4.0 (50: 50, v/v) at 1.2 mL/min with UV detection at 210 nm. The method was linear over the concentration ranges of 5.0–200.0 μg/mL, 2.0–80.0 μg/mL and 1.0–25.0 μg/mL with lower detection limits of 0.21 μg/mL, 0.10 μg/mL and 0.11 μg/mL for TM, BM and LP, respectively. The method was applied for the determination of two fixed-dose combination eye drops for the treatment of glaucoma, containing TM together with either BM or LP. Commercial samples of single-ingredient ophthalmic solutions containing the studied drugs were also successfully analyzed. The results obtained by the proposed method were favorably compared with those obtained by the comparison methods using Student’s t test and the variance ratio F test.     

Chemometrics-Assisted UV Spectrophotometric and RP-HPLC Methods for the Simultaneous Determination of Tolperisone Hydrochloride and Diclofenac Sodium in their Combined Pharmaceutical Formulation

Chemometrics-assisted UV spectrophotometric and RP-HPLC methods are presented for the simultaneous determination of tolperisone hydrochloride (TOL) and diclofenac sodium (DIC) from their combined pharmaceutical dosage form. Chemometric methods are based on principal component regression and partial least-square regression models. Two sets of standard mixtures, calibration sets, and validation sets were prepared. Both models were optimized to quantify each drug in the mixture using the information included in the UV absorption spectra of the appropriate solution in the range 241–290 nm with the intervals λ = 1 nm at 50 wavelengths. The optimized models were successfully applied to the simultaneous determination of these drugs in synthetic mixture and pharmaceutical formulation. In addition, an HPLC method was developed using a reversed-phase C18 column at ambient temperature with a mobile phase consisting of methanol:acetonitrile:water (60:30:10 v/v/v), pH-adjusted to 3.0, with UV detection at 275 nm. The methods were validated in terms of linearity, accuracy, precision, sensitivity, specificity, and robustness in the range of 3–30 μg/mL for TOL and 1–10 μg/mL for DIC. The robustness of the HPLC method was tested using an experimental design approach. The developed HPLC method, and the PCR and PLS models were used to determine the amount of TOL and DIC in tablets. The data obtained from the PCR and PLS models were not significantly different from those obtained from the HPLC method at 95% confidence limit.     

Development and Validation of a Stability-Indicating RP-HPLC Method for the Estimation of Drotaverine Impurities in API and Pharmaceutical Formulation

A sensitive, stability-indicating gradient RP-HPLC method with PDA detection has been developed for the simultaneous analysis of drotaverine impurities in active pharmaceutical ingredient (API) and pharmaceutical formulations. Efficient chromatographic separation was achieved on an XTerra RP18, 150 × 4.6 mm, 5 μm column using gradient elution at 230 nm detection wavelength. The optimized mobile phase consisted of a 0.02 M potassium dihydrogen orthophosphate buffer of pH 3.0 as solvent A and acetonitrile as solvent B. The flow rate of the mobile phase was 1.0 mL min⁻¹ with a column temperature of 25°C. The method showed linearity over the range of 0.251–10.033 μg/mL, 0.231–9.995 μg/mL, 0.230–10.089 μg/mL, 0.334–10.011 μg/mL, and 0.324–10.050 μg/mL for impurities 1, 2, 3, 4, and drotaverine, respectively, with a correlation coefficient greater than 0.999. The relative retention times and relative response factors of impurities 1, 2, 3, 4 were 0.36, 0.90, 1.42, 1.55 and 1.04, 0.84, 1.10, 1.30, respectively. The drotaverine formulation sample was subjected to the stress conditions of acid, base, oxidative, thermal, humidity, and photolytic degradation. Drotaverine was found to degrade significantly in peroxide, base, and heat stress conditions. The degradation products were well-resolved from drotaverine and its impurities. The peak purity test results confirmed that the drotaverine peak was homogenous and pure in all stress samples and the mass balance was found to be more than 98%, thus proving the stability-indicating power of the method. The developed method was validated according to ICH guidelines with respect to specificity, linearity, limit of detection and quantification, accuracy, precision, and robustness.     

Development and Validation of New HPLC Method for Simultaneous Estimation of L-Lysine Hydrochloride and L-Carnitine-L-Tartrate in Pharmaceutical Dosage Form

A new analytical method is developed and validates for simultaneous estimation of L-lysine hydrochloride and L-carnitine-L-tartrate in single pharmaceutical dosage form by means of high resolution HPLC. The chromatographic procedure was carried out using C₁₈-5 μm (4.6 mm × 250 mm), column. Optimally suited mobile phase was made to run in an isocratic elution mode whose composition was 10 mM of potassium dihydrogen phosphate adjusted with triethylamine to a pH of 7.5 and pumped at a flow rate of 0.50 ml/min through chromatographic system. The detector''s wavelength was 214 nm. The accuracy of the analytical method was determined keeping into account the recovery of analytes, which in this case remains well within the accepted standards that is 95-105%. Detection limit for L-lysine hydrochloride and L-carnitine-L-tartrate are 1.47 μg/ml and 0.85 μg/ml while quantitation limit for L-lysine hydrochloride and L-carnitine-L-tartrate is 4.41 and 2.55 μg/ml, respectively. All the statistical results were validated performing precision, accuracy, linearity, specificity studies for analytes concentration from 70-130%. The outcome of results confirmed that the method was in consonance with the acceptance criteria.     

High-Performance Liquid Chromatographic and High-Performance Thin-Layer Chromatographic Method for the Quantitative Estimation of Dolutegravir Sodium in Bulk Drug and Pharmaceutical Dosage Form

Simple, sensitive, precise, and specific high-performance liquid chromategraphic (HPLC) and high-performance thin-layer chromatographic (HPTLC) methods for the determination of dolutegravir sodium in bulk drug and pharmaceutical dosage form were developed and validated. In the HPLC method, analysis of the drug was carried out on the ODS C₁₈ column (150 × 4.6 mm, 5 μm particle size) using a mixture of acetonitrile: water (pH 7.5) in the ratio of 80:20 v/v as the mobile phase at the flow rate 1 mL/min at 260 nm. This method was found to be linear in the concentration range of 5–35 μg/mL. The peak for dolutegravir sodium was observed at 3.0 ± 0.1 minutes. In the HPTLC method, analysis was performed on aluminum-backed plates pre-coated with silica gel G60 F₂₅₄ using methanol: chloroform: formic acid in the proportion of 8:2:0.5 v/v/v as the mobile phase. This solvent system was found to give compact spots for dolutegravir sodium with the Rf value 0.77 ± 0.01. Densitometric analysis of dolutegravir sodium was carried out in the absorbance mode at 265 nm. Linear regression analysis showed good linearity with respect to peak area in the concentration range of 200–900 ng/spot. The methods were validated for precision, limit of detection (LOD), limit of quantitation (LOQ), accuracy, and specificity. Statistical analysis showed that both of the methods are repeatable and specific for the estimation of the said drug. The methods can be used for routine quality control analysis of dolutegravir sodium.     

High-throughput liquid chromatography tandem mass spectrometry method for simultaneous determination of fampridine,paroxetine, and quinidine in rat plasma: Application to in vivo perfusion study

A selective and high-throughput liquid chromatography–mass spectrometry method has been developed and validated for the simultaneous quantification of paroxetine, fampridine, and quinidine in rat plasma using imipramine as an internal standard. Following protein precipitation extraction, the analytes and internal standard were run on X Bridge C18 column (150 mm × 4.6 mm, 5 μm) using a gradient mobile phase consisting of 5mM ammonium formate in water (pH 9.0) and acetonitrile in a flow gradience program. The precursor and product ions of the drugs were monitored on a triple quadrupole instrument operated in the positive ionization mode. The method was validated over a concentration range of 0.1–100 ng/mL for all the three analytes, with relative recoveries ranging from 69% to 82%. The intra- and interbatch precision (percent coefficient of variation) across four validation runs were less than 13.4%. The accuracy determined at four quality control (QC) levels (lower limit of quantitation, low QC, medium QC, and high QC) was within ±6.5% of coefficient of variation values. The method proved highly reproducible and sensitive, and was successfully applied in a pharmacokinetic study after single-dose oral administration to rats and also in perfusion study sample analysis.     

Bioanalytical Method for Carbocisteine in Human Plasma by Using LC-MS/MS: A Pharmacokinetic Application

A simple, sensitive, and selective LC-MS/MS method was developed and validated for the quantification of carbocisteine in human plasma. Rosiglitazone was used as the internal standard and heparin was used as the anticoagulant. The chromatographic separation was performed by using the Waters Symmetry Shield RP 8, 150 × 3.9 mm, 5 μ column at 40°C with a mobile phase consisting of a mixture of methanol and 0.5% formic acid solution in a 40:60 proportion. The flow rate was 500 μl/min along with a 5 μl injection volume. Protein precipitation was used as the extraction method. Mass spectrometric data were detected in positive ion mode. The MRM mode of the ions for carbocisteine was 180.0 > 89.0 and for rosiglitazone it was 238.1 > 135.1. The method was validated in the concentration curve range of 50.000 ng/mL to 6000.000 ng/mL. The retention times of carbocisteine and the internal standard rosiglitazone were approximately 2.20 and 3.01 min, respectively. The overall run time was 4.50 min. This method was found suitable to analyze human plasma samples for the application in pharmacokinetic and BA/BE studies.     

Development and validation of stability-indicating high performance liquid chromatography method to analyze gatifloxacin in bulk drug and pharmaceutical preparations

Quantitative determination of gatifloxacin in tablets, solid lipid nanoparticles (SLNs) and eye-drops using a very simple and rapid chromatographic technique was validated and developed. Formulations were analyzed using a reverse phase SUPELCO® 516 C-18-DB, 50306-U, HPLC column (250 mm × 4.6 mm, 5 μm) and a mobile phase consisting of disodium hydrogen phosphate buffer:acetonitrile (75:25, v/v) and with orthophosphoric acid pH was adjusted to 3.3 The flow rate was 1.0 mL/min and analyte concentrations were measured using a UV-detector at 293 nm. The analyses were performed at room temperature (25 ± 2 °C). Gatifloxacin was separated in all the formulations within 2.767 min. There were linear calibration curves over a concentration range of 4.0–40 μg.mL⁻¹ and correlation coefficients of 0.9998 with an average recovery above 99.91%. Detection of analyte from different dosage forms at the same R_t indicates the specificity and stability of the developed method.     

Development and Validation of a Liquid Chromatographic Method for Estimation of Dicyclomine Hydrochloride,Mefenamic Acid and Paracetamol in Tablets

Liquid chromatographic method was developed for simultaneous quantitative determination of dicyclomine hydrochloride, mefenamic acid and paracetamol in their combined dosage form. The separation was achieved using a C₁₈ column (250×4.6 mm id, 5 μm) using acetonitrile:20 mM potassium dihydrogen phosphate 70:30 (v/v) adjusted to pH 4 using orthophosphoric acid as mobile phase at a flow rate of 1 ml/min and detection at 220 nm. Separation was completed within 12 min. The retention times of dicyclomine hydrochloride, mefenamic acid and paracetamol were 3.8, 9.3 and 2.5 minutes respectively. The proposed method was found to have linearity in concentration range of 10–100 μg/ml for dicyclomine hydrochloride, 0.05-10 μg/ml for mefenamic acid and 0.1−20 μg/ml for paracetamol. The developed method has been statistically validated and was found to be simple, precise, reproducible and accurate. The developed and validated method was successfully used for the quantitative analysis of commercially available dosage form.     

Simultaneous Determination and Pharmacokinetic Study of Losartan,Losartan Carboxylic Acid,Ramipril, Ramiprilat,and Hydrochlorothiazide in Rat Plasma by a Liquid Chromatography/Tandem Mass Spectrometry Method

The monitoring of the plasmatic concentrations of cardiovascular drugs is crucial for understanding their pharmacokinetics and pharmacodynamics. A simple, sensitive, specific, and high-throughput liquid chromatography/tandem mass spectrometry (LC–MS/MS) method was developed and validated for the simultaneous estimation and pharmacokinetic study of losartan (LOS), losartan carboxylic acid (LCA), ramipril (RAM), ramiprilate (RPT), and hydrochlorothiazide (HCZ) in rat plasma using irbesartan (IBS) and metolazone (MET) as internal standards (ISs). After solid phase extraction (SPE), analytes and ISs were separated on an Agilent Poroshell 120, EC-C18 (50 mm × 4.6 mm, i.d., 2.7 μm) column with a mobile phase consisting of methanol/water (85:15, v/v) containing 5 mmol/L ammonium formate and 0.1% formic acid at a flow rate of 0.4 mL/min. The precursor → product ion transitions for the analytes and ISs were monitored on a triple quadrupole mass spectrometer, operating in the multiple reaction monitoring (MRM) mode and switching the electrospray ionization (ESI) mode during chromatography from positive (to detect LOS, LCA, RAM, RPT, and IBS) to negative (to detect HCZ and MET). The method was validated as per the FDA guidelines and it exhibited sufficient specificity, accuracy, and precision. The method was found to be linear in the range of 3–3000 ng/mL for LOS and LCA, 0.1–200 ng/mL for RAM and RPT, and 1–1500 ng/mL for HCZ. The described method was successfully applied to the preclinical pharmacokinetic study of analytes after oral administration of a mixture of LOS (10 mg/kg), RAM (1 mg/kg), and HCZ (2.5 mg/kg) in rats.     

An Experimental Design Approach for Impurity Profiling of Valacyclovir-Related Products by RP-HPLC

Impurity profiling has become an important phase of pharmaceutical research where both spectroscopic and chromatographic methods find applications. The analytical methodology needs to be very sensitive, specific, and precise which will separate and determine the impurity of interest at the 0.1% level. Current research reports a validated RP-HPLC method to detect and separate valacyclovir-related impurities (Imp-E and Imp-G) using the Box-Behnken design approach of response surface methodology. A gradient mobile phase (buffer: acetonitrile as mobile phase A and acetonitrile: methanol as mobile phase B) was used. Linearity was found in the concentration range of 50–150 μg/mL. The mean recovery of impurities was 99.9% and 103.2%, respectively. The %RSD for the peak areas of Imp-E and Imp-G were 0.9 and 0.1, respectively. No blank interferences at the retention times of the impurities suggest the specificity of the method. The LOD values were 0.0024 μg/mL for Imp-E and 0.04 μg/mL for Imp-G and the LOQ values were obtained as 0.0082 μg/mL and 0.136 μg/mL, respectively, for the impurities. The S/N ratios in both cases were within the specification limits. Proper peak shapes and satisfactory resolution with good retention times suggested the suitability of the method for impurity profiling of valacyclovir-related drug substances.     

Development and Validation of a Stability-Indicating RP-HPLC Method for the Assay of Pristinamycin in Bulk and Tablet Dosage Form

Pristinamycin is an antibiotic used mainly in the treatment of Staphylococcus infections. The aim of this study was to develop a rapid and simple stability-indicating RP-HPLC method for the determination of pristinamycin in tablet dosage form. Pristinamycin was eluted on the ACE-5, C₁₈-HL, 250 x 4.6 mm, 5 µm analytical column with a mobile phase consisting of 0.2% orthophosphoric acid and acetonitrile 63:37 v/v, pumped at 1.5 ml/min flow rate. The column was maintained at 40°C and 10 μl of the solutions were injected. UV detection was performed at 206 nm. The procedure separated pristinamycin and its potential degradation products in an overall analysis time of less than 10 min with pristinamycin eluting at about 3 min. The method was validated according to the regulatory guidelines with respect to specificity, precision, accuracy, linearity, and robustness. Forced degradation studies were also performed for pristinamycin bulk drug samples to demonstrate the stability-indicating power of the HPLC method. The % RSD of system precision and method precision was found to be 0.64 and 1.49%, respectively. The procedure provided a linear response over the concentration range 25–150 μg/ml (r = 0.9998). Finally, the applicability of the method was evaluated in the tablet dosage form as well as in stability samples.     

Quality assessment of Fritillariae Thunbergii Bulbus sold in Taiwan markets using a validated HPLC-UV method combined with hierarchical clustering analysis

The present paper describes the development of a high performance liquid chromatography-ultraviolet (HPLC-UV) detection method for quantitative determination of peimine and peiminine in Fritillariae Thunbergii Bulbus (FTB). Separation was achieved using a conventional XBridge™Shield RP 18 column (250 mm × 4.6 mm, internal diameter 3.5 μm) with photodiode array detection at 190–400 nm for UV spectra and 220 nm for quantification. The mobile phase consisted of (A) 0.03% diethylamine aqueous solution and (B) acetonitrile eluted by an isocratic procedure at 45:55 (A:B) over 25 minutes. The method was validated for linearity, limits of detection (LOD) and quantification (LOQ), inter- and intra-day precisions, repeatability, stability, and recovery. All the validation results were satisfactory. The developed method was then applied to assay the contents of the two chemical markers in all the FTB samples collected. Based on the contents of the two analytes, hierarchical clustering analysis (HCA) was performed to reveal the similarities and differences of the samples.     

Quality by Design-Based Development of a Stability-Indicating RP-HPLC Method for the Simultaneous Determination of Methylparaben,Propylparaben, Diethylamino Hydroxybenzoyl Hexyl Benzoate,and Octinoxate in Topical Pharmaceutical Formulation

A stability-indicating RP-HPLC method has been developed and validated for the simultaneous determination of methylparaben (MP), propylparaben (PP), diethylamino hydroxybenzoyl hexyl benzoate (DAHHB), and octinoxate (OCT) in topical pharmaceutical formulation. The desired chromatographic separation was achieved on the Kinetex^TM C18 (250 × 4.6 mm, 5 μm) column using gradient elution at 257 nm detection wavelength. The optimized mobile phase consisted of a buffer : acetonitrile : tetrahydrofuran (60 : 30 : 10, v/v/v) as solvent A and acetonitrile : tetrahydrofuran (70 : 30, v/v) as solvent B. The method showed linearity over the range of 0.19–148.4 μg/mL, 0.23–15.3 μg/mL, 1.97–600.5 μg/mL, and 1.85–451.5 μg/mL for MP, PP, DAHHB, and OCT, respectively. Recovery for all the components was found to be in the range of 98–102%. The stability-indicating capability of the developed method was established by analysing the forced degradation samples in which the spectral purity of MP, PP, DAHHB, and OCT, along with the separation of the degradation products from the analyte peaks, was achieved. The proposed method was successfully applied for the quantitative determination of MP, PP, DAHHB, and OCT in the lotion sample. The design expert with ANOVA software with the linear model was applied and a 2⁴ full factorial design was employed to estimate the model coefficients and also to check the robustness of the method. Results of the two-level full factorial design, 2⁴ with 20 runs including four centrepoint analysis based on the variance analysis (ANOVA), demonstrated that all four factors, as well as the interactions of resolution between DAHHB and OCT are statistically significant.     

Trace residue analysis of dicyandiamide,cyromazine, and melamine in animal tissue foods by ultra-performance liquid chromatography

An effective sample preparation procedure using an accelerated solvent extraction (ASE) procedure, followed by cleaning with melamine molecularly imprinted polymers solid-phase extraction (MISPE) was developed. A novel and highly sensitive ASE–MISPE–ultraperformance liquid chromatography (UPLC) method was developed for effective separation and simultaneous determination of dicyandiamide (DCD), cyromazine (CYR), and melamine (MEL) in complex animal tissue foods. Under optimized conditions, good linearity was achieved with a correlation coefficient (r) of 0.9999 in the range of at least two orders of magnitude. The limit of quantification of the method was 1.7 μg/kg, 5.0 μg/kg, and 3.2 μg/kg for DCD, MEL, and CYR, which was three orders of magnitude smaller than the maximum residue limits (MRLs). The intra- and inter-day precisions (in terms of the relative standard deviation, RSD) of the three analytes were in the range of 1.7–3.1% and 3.1–6.3%, respectively. The average recoveries of analytes from blank chicken, beef, mutton, pork, and pig liver samples spiked with the three levels varied from 91.2% to 107% with RSD of 1.7–8.3% for DCD, 89.0–104% with RSD of 2.1–6.1% for CYR, and 94.8–105% with RSD of 1.1–6.6% for MEL. The proposed method has the characteristics of speed, sensitivity, and accuracy, and can be used for the routine determination of DCD, CYR, and MEL at the μg/kg level in complex animal tissue foods.     

Determination of cannabinoids in hemp oil based cosmetic products by LC-tandem MS

Cosmetic products containing hemp seed oil as permitted raw materials required the specific compound delta-9-tetrahydrocannabinol (THC) below 10 μg/g. THC was the main psychoactive constituent of cannabis. Since hemp seed oil became an increasingly popular ingredient in cosmetics over the last few years, an efficient and reliable analytical method for THC and other cannabinoids in cannabis-infused cosmetic products was in need. A liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for the determination of delta-9-tetrahydrocannabinol (THC), cannabidiol (CBD), and cannabinol (CBN) in hemp seed oil based cosmetic products was developed. Method validation was performed by fertilizing blank samples with analytes and internal standards (THC-d₃, CBD-d₃, and CBN-d₃). Chromatographic method utilized a Xbridge BEH Shield RP18 column with gradient elution containing 10 mM ammonium formate in water and methanol provided successful separation of THC, CBD, and CBN in cosmetic matrix. The combination of MS detection in positive electrospray ionization (ESI) and multiple reaction monitoring (MRM) mode offered rapid run time 13 minutes with limit of quantification (LOQ) of 0.05 μg/g. The intra- and inter-day recoveries were 79.23–114.04% and 83.55–111.61% with spiking levels ranged between 0.05 μg/g and 0.5 μg/g, respectively. Surveillance results of 90 cosmetic products showed 22, 34, and 5 products containing THC (0.06–1777 μg/g), CBD (0.47–37217 μg/g), and CBN (2.2–25.2 μg/g), respectively. This validated method offered accurate, reliable, and fast way for the determination of drug contaminations including THC, CBD, and CBN in cosmetics. The surveillance results for commercial cosmetic products purchased in Taiwan between 2018–2020 provided valuable background references for THC, CBD, and CBN in hemp seed oil based cosmetic products, and could be used for administration purpose.     

Rapid and Sensitive Reverse-phase High-performance Liquid Chromatography Method for Estimation of Ketorolac in Pharmaceuticals Using Weighted Regression

A reliable, rapid and sensitive isocratic reverse phase high-performance liquid chromatography method has been developed and validated for assay of ketorolac tromethamine in tablets and ophthalmic dosage forms using diclofenac sodium as an internal standard. An isocratic separation of ketorolac tromethamine was achieved on Oyster BDS (150×4.6 mm i.d., 5 μm particle size) column using mobile phase of methanol:acetonitrile:sodium dihydrogen phosphate (20 mM; pH 5.5) (50:10:40, %v/v) at a flow rate of 1.0 ml/min. The eluents were monitored at 322 nm for ketorolac and at 282 nm for diclofenac sodium with a photodiode array detector. The retention times of ketorolac and diclofenac sodium were found to be 1.9 min and 4.6 min, respectively. Response was a linear function of drug concentration in the range of 0.01-15 μg/ml (R²=0.994; linear regression model using weighing factor 1/x²) with a limit of detection and quantification of 0.002 μg/ml and 0.007 μg/ml, respectively. The % recovery and % relative standard deviation values indicated the method was accurate and precise.