Chromatographic Method For Simultaneous Determination Research Articles

A Simple and Reliable Liquid Chromatographic Method for Simultaneous Determination of Five Benzodiazepine Drugs in Human Plasma

Benzodiazepines (BZDs) are one of the most important drugs that have been used in the treatment of neuropsychological disorders. Indeed, BZDs are abused by drug addicts regardless of their therapeutic uses. Therefore, it was important in forensic and clinical toxicology to reach an easy and reliable method for the screening and quantification of BZDs in the human plasma matrix. In the current work, five BZDs, namely bromazepam, clonazepam, lorazepam, nordiazepam and diazepam were simultaneously separated and detected by a simple and reliable RPLC method in a human plasma matrix. Isocratic mobile elution consisting of 20 mmol L−1 phosphate buffer (pH 7.0) and methanol (50:50, v/v) on a Symmetry C18 column was employed. The flow rate, wavelength and column temperature were fixed at 1.0 mL min−1, 214 nm and 40 °C, respectively. The proposed method was validated, giving a linearity within the concentration ranges 5–500 ng mL−1 for bromazepam and diazepam, 3–500 ng mL−1 for clonazepam and lorazepam and 1–500 ng mL−1 for nordiazepam with a determination coefficient (R2) more than 0.9992. The LOD values for the selected BZDs ranged from 0.54 to 2.32 and from 1.78 to 7.65 ng mL−1 for standard methanolic and plasma matrices, respectively. Precision, accuracy, selectivity, stability, and robustness were some of the terms considered in validating the current RPLC method. Based on these results, a simple and reliable RPLC method was successfully applied to quantify BZDs in human plasma matrix appearing with recoveries ranging from 96.5 to 107.5% and interday RSD less than 4%. The current developed method was useful for rapidly screening the most commonly used BZDs in the market within their therapeutic concentration ranges.

Analysis of Fixed-Dose Combination of Three Antihypertensive Drugs by a Green and Quality by Design Approach.

This paper presents the result of a combined employment of Analytical Quality-by-Design and Green Analytical Chemistry principles for the development of a robust high-performance liquid chromatography method for simultaneous determination of fixed-dose combination of three drugs, perindopril tert-butylamine, amlodipine besylate and indapamide. Optimum conditions were achieved on ZORBAX Eclipse XDB-C18 column (150mm × 4.6mm, 5μm particle size), the mobile phase comprising acetonitrile and phosphate buffer (30mM, pH2.7) in the ratio 34:66 (v/v), the flow rate of 1mLmin-1, injection volume of 10μL and UV detection at 210nm. By assigning the design space from the overlay plot, the regions within which the robustness of the method is achieved were defined and confirmed by Dong's algorithm calculations. The proposed method was validated and shown to be applicable for the determination of the three drugs in commercially available tablets. In addition, the impact of the method on the environment was assessed through four different analytical tools: National Environmental Methods Index, Analytical Eco-Scale, Green Analytical Procedure Index and Assessment of Green Profile. The proposed method was determined to be greener, with minimal impact on the environment with regard to waste production, energy consumption and use of hazardous chemicals.

Rapid simultaneous determination of coumarins and organic acids in notopterygium by an isocratic micellar liquid chromatography based on Box-Behnken design

This work has developed an isocratic micellar liquid chromatographic method for simultaneous determination of nodakenin, isoimperatorin, psoralen, ferulic acid, and chlorogenic acid in notopterygium and notopterygium processed products for the first time. Analytes were successfully separated within 15 min. The optimized chromatographic conditions were obtained by Box-Behnken design optimization, and the mobile phase consisted of 0.064 M sodium lauryl sulfate aqueous solution and 8.15% n-pentanol with a pH value of 3.04. The analytes were eluted isocratically through a C18 column at a flow rate of 1 mL/min. The linear ranges, limit of detection, limit of quantitation, recovery, intra-day and inter-day precision of the proposed method were validated according to ICH guidelines. The proposed method was successfully applied to the quantitative the 5 active components in notopterygium and its processed products. It is a simple, efficient, and low-cost analytical method that provides an alternative method for the determination of the 5 active ingredients in notopterygium.

Development and validation of liquid chromatography method for simultaneous determination of multiclass seven antibiotic residues in chicken tissues

BackgroundAntibiotics are routinely used on poultry for therapy and prevention of diseases and to enhance animal growth. The objective of this study was to develop and validate a sensitive and reliable liquid chromatography with UV detection (LC-UV) method for the simultaneous determination of seven multiclass antibiotic residues (amoxicillin, ampicillin, penicillin, sulfamethoxazole, gentamicin, ciprofloxacin, and erythromycin) in chicken tissues.MethodsThe liquid chromatography method with UV detection was optimized for complete separation of the seven selected antibiotic compounds with reversed phase and isocratic elution using Hypersil BDS-C18 (3 µm, 100 mm × 4 mm) column. The mobile phase consisted a ratio of 0.05 M Na2HPO4, acetonitrile and methanol (70:10:20), at UV absorption wavelength of 230 nm. The column thermostat was set at 40 °C, the mobile phase flow rate was 1 mL min−1, and the injection volume was 20 μL.ResultsAll the seven standard compounds were eluted within 14 min. The results for: linearity, precision, sensitivity, accuracy, specificity, decision limit (CCα), detection capability (CCβ), suitability and method robustness were validated according to the criteria of Commission Decision 2002/657/EC guidelines. Calibration plot correlation coefficients ranged from 0.9983 to 0.9998 and the percent relative standard deviations for repeated analysis were below 5% indicating acceptable method precision. The limits of detection (LODs) and quantification (LOQs) ranged from 0.098–0.255 μg kg−1 to 0.297–0.574 μg kg−1, respectively. The accuracy study yielded recoveries in the ranges 98.1–107% for the pure compounds and 94.0–102% for the spiked drug free chicken tissue samples.ConclusionsThe method was found to be appropriate for simultaneous determination of five different classes of seven antibiotic residues in chicken tissues. Furthermore, this is the first instance for the simultaneous determination of seven multiclass, multi-residues analysis using LC-UV from chicken tissue samples. This is a cost-effective and alternative method with simple instrumentation approach for laboratories that lack highly specialized state-of-the-art instrumentation.

A new sensitive HPLC/UV method for simultaneous determination of paclitaxel, sorafenib and omeprazole in standard solutions and spiked plasma: Application to in-vitro and in-vivo evaluation of paclitaxel polymeric nanoformulations

Purpose: To develop a simple, novel, sensitive and rapid reverse phase high performance liquid chromatographic method for simultaneous determination of paclitaxel, sorafenib and omeprazole in standard solutions and spiked human plasma and its application to the in-vitro and in-vivo evaluation of paclitaxel polymeric nanoparticle formulations.Methods: The method was tested for the assessment of paclitaxel, omeprazole and sorafenib using tamoxifen citrate as internal standard. The analysis was performed at a wavelength of 235 nm using Thermo HS C18 column, 40 °C column oven temperature, acetonitrile and water (70:30 v/v, pH 3.37 adjusted with phosphoric acid) as a mobile phase and at a flow rate of 0.8 ml/min. All analytes were extracted by simple protein precipitation method using acetonitrile. The linearity was assessed in the concentration range of 1 - 2000 ng/mL for paclitaxel, omeprazole and sorafenib.Results: The developed chromatographic method effectively separated omeprazole, paclitaxel, sorafenib and IS with retention time of 3.93, 5.18, 6.43 and 9.93 min, respectively. The chromatograms of the three target compounds and IS showed good resolution and peak separation. The LOD of the method was 1, 5 and. 5 ng/mL while the LOQ was 2, 7.5 and 10 ng/mL, for paclitaxel, sorafenib and omeprazole, respectively.Conclusion: The proposed RP-HPLC–UV method for the assessment of paclitaxel, sorafenib and omeprazole in standard solutions and spiked plasma is simple, economical, sensitive and robust. The method is also suitable for the analysis of paclitaxel in nanoformulations and for its pharmacokinetic studies in an animal model.

Validation of an innovative analytical method for simultaneous quantification of curcumin and fluconazole using high-performance liquid chromatography from nanostructured lipid carriers.

Vulvovaginal candidiasis is a public health problem with a high incidence among female patients. Currently, there is an increase in the identification of Candida spp. resistant to current therapy, making it necessary to search for new therapeutic alternatives. The synergistic potential of curcumin with fluconazole is described in the literature. However, due to its high lipophilicity, it is necessary to use drug-delivery systems to adequately explore its potential, among which is the nanostructured lipid carrier. However, to date, there is no validated method of high-performance liquid chromatography for simultaneous determination of fluconazole and curcumin in the literature. Thus, the present work developed a high-performance liquid chromatography method for simultaneous determination of fluconazole and curcumin co-encapsulated in nanostructured lipid carrier which was validated according to the International Conference on Harmonization (Technical Requirements for Registration of Pharmaceuticals for Human Use) - Q2 (R1) and the Food and Drug Administration - Guidance for Bioanalytical Method. The method was applied to determine the encapsulation efficiency and drug-loading of curcumin and fluconazole in nanostructured lipid carriers. The developed method proved to be selective, precise, accurate, and robust for the simultaneous determination of both drugs, enabling the quantification of encapsulation efficiency and drug-loading of curcumin and fluconazole in nanostructured lipid carriers.

Systemic Optimization and Validation of Normal and Reversed-Phase Eco-Friendly Chromatographic Methods for Simultaneous Determination of Paracetamol and Phenylephrine Hydrochloride in the Presence of Paracetamol Impurities.

Chromatographic behavior of different substances in normal and reversed phases is an interesting area in the scientific community. The work aimed to optimize and validate chromatographic separation methods for simultaneous determination of paracetamol (PAR) and phenylephrine HCl (PHE) in the presence of PAR impurities, namely p-aminophenol, p-nitrophenol, acetanilide, and p-chloroacetanilide with further quantification of these toxic impurities. TLC method based on normal phase separation was carried out on aluminum sheets of silica gel 60 F254 using ethanol:chloroform:ammonia as a developing system, followed by densitometric measurements. While HPLC is based on reversed phase separation using a C18 column against acetonitrile:phosphate buffer pH 5 as a mobile phase. PAR and PHE were determined by the TLC-densitometric method in concentration ranges of 3-25 and 0.1-3 µg/band, respectively, and determined by the HPLC method over concentration ranges of 5-400 and 2-80 µg/mL, respectively. Both methods were optimized and validated. Furthermore, they were successfully applied for pharmaceutical formulations with precision <2%. Moreover, results of a statistical comparison with the official methods confirm the methods' validity claims. Two eco-friendly chromatographic methods were developed to determine PAR and PHE in their binary mixtures, pharmaceutical formulations, and in the presence of PAR-related impurities with further quantification of these toxic impurities. These simple chromatographic methods are the first methods developed for simultaneous determination of PAR and PHE in the presence of PAR-related impurities.

High-Performance Liquid Chromatography Method for Simultaneous Determination of Bisphenols in Plastic Packed Dry Fruits Using Multi-walled Carbon Nanotubes as Solid Phase Extraction Sorbent

Background: Bisphenols A (BPA), bisphenol S (BPS), and bisphenol F (BPF) are manufactured chemicals found in food packaging, drink containers, lotions, toys, plastic PVC flooring, and water pipes. The aim of this work is to develop simple, rapid and reliable high-performance liquid chromatography with fluorescence detector (HPLC-FLD) method for simultaneous determination of bisphenols A (BPA), bisphenol F (BPF), and bisphenol S (BPS) in plastic packed dry fruits collected from Saudi Arabia markets. Methods: BPA, BPS and BPF in plastic packed dry fruits samples were extracted and clean up using packed Multi-Walled Carbon Nanotubes (MWCNTs) mini-column followed by analysis using HPLC-FLD. Results: The three BPs were separated within less than 12 min. The method was validated in terms of linearity, limit of detection (LOD), limit of quantification (LOQ), precision (repeatability) and accuracy (recovery). Good linearity was obtained in the concentration range of 62.25-10000 μg/L for BPS and 6.25-1000 μg/L for BPA and BPF. The LODs and LOQs were found to be 1.07, 12.09, and 0.9939 μg/L and 3.56, 40.32 and 3.13 μg/L for bisphenols BPA, BPS, and BPF, respectively. Recoveries for analytes in the samples were all within the range of 87% to 104%. Conclusion: The method was successfully applied to real dry fruit samples (i.e, dry date (Ajwa), apricot, dry grapes and figs. The results obtained revealed that all of the tested BPs were present in the samples.

Eco-Friendly Chromatographic Methods for Determination of Acemetacin and Indomethacin; Greenness Profile Assessment.

The green chemistry approach was developed for the purpose of saving the environment by using green solvents. Applying green analytical chemistry principles to traditional methods is considered a challenge. Acemetacin is a commonly used analgesic prodrug that bioactivates to indomethacin. Developing two simple, eco-friendly chromatographic methods for simultaneous determination of acemetacin and indomethacin. The first method is HPLC-DAD. Separation was performed on a Waters XBridge® Shield RP18 (250 × 4.6 mm, 5 µm) analytical column with ethanol-ammonium acetate buffer (50 mM, pH 3.5 ± 0.1; 60:40, v/v) as a mobile phase at a flow rate of 1 mL/min at 25 ± 0.5°C and UV detection at 254 nm. The other method is TLC coupled with densitometric quantification using pre-coated silica TLC plates and butanol-ethyl acetate (70:30, v/v) elution system. The plates were scanned at 254 nm. Both methods were validated according to International Conference on Harmonization guidelines. Linearity was confirmed for both over a concentration range of 1-100 µg/mL for the HPLC method and 0.2-7 µg/band for TLC-densitometric method. The methods' greenness was evaluated by the National Environmental Methods Index, Eco-Scale, Green Analytical Procedure Index metrics and Analytical GREEnness Metric Approach. The proposed methods were found to be suitable for determination of studied drugs in their marketed formulations and is suggested for routine analysis in quality control laboratories. The developed HPLC method shortened the elution time of the analyzed drugs saving more time and money and the TLC method lowered the drugs' detection limit. HPLC and TLC methods were validated for the assay of acemetacin and indomethacin. The methods' greenness was evaluated and compared to published methods. The developed HPLC method shortened the elution time of the analyzed drugs, saving time and money and the TLC method lowered the drugs' detection limit.

Using Design Space and Response Surface Methodology for developing a liquid chromatography method for simultaneous determination of five statins in pharmaceutical form

AbstractThis study describes the development of a method allowing the simultaneous separation and quantification of five statins by High performance liquid chromatography/Diode Array Detector (HPLC/DAD). Optimization was accomplished using chemometric tools such as the Design Space (DS) and Response Surface Methodology (RSM). Central Composite Design (CCD) and DS were applied for the optimization of the chromatographic procedure as well as the robustness of the chromatographic method by taking the ratio of the percentage of acetonitrile (%ACN) Buffer solution, the pH and the mobile phase flow rate as critical parameters. Satisfactory results were obtained after the optimization phase with a percentage of mobile phase equal to 46.19%, a pH of 4.16 and the flow rate is 1.4 mL min−1 by setting the resolution limits above 6, and the target retention time of 20 min. Using the DS and CCD approach, we have developed a robust and reliable procedure for the simultaneous and accurate separation and quantification of the five statins.

Factorial design-assisted reversed phase-high performance liquid chromatography method for simultaneous determination of fluconazole, itraconazole and terbinafine.

A 23 full factorial design model was used for the development of a new high performance liquid chromatography method with UV detection to estimate three antifungal drugs simultaneously. Fluconazole (FLU), itraconazole (ITR) and terbinafine (TRH) are co-administered for severe fungal infections. They have been determined using MOS-1 Hypersil C18 column and an isocratic eluent; methanol 95% and phosphate buffer 5% with 0.001% triethylamine. The pH was adjusted to 7, and the flow rate was 0.7 ml min−1. The three drugs were separated within less than 7 min at 210 nm. The developed method gave a linear response over 5–80 µg ml−1, 5–50 µg ml−1 and 1–50 µg ml−1 for FLU, ITR and TRH, respectively. It showed detection limits of 0.88, 0.29 and 0.20 µg ml−1 and quantification limits of 2.66, 0.88 and 0.60 µg ml−1 for the three drugs, respectively. The design of the experiment facilitated the optimization of different variables affecting the separation of the three drugs. The sensitivity of the designed method permitted the simultaneous estimation of ITR and TRH in spiked human plasma successfully.

Improved ultra-high performance liquid chromatographic method for simultaneous determination of five gout-related metabolites in human serum.

Creatinine and purines are gout-related metabolites commonly quantified by liquid chromatography coupled with ultraviolet and mass spectrometry. However, the high cost of liquid chromatography coupled with mass spectrometry hindered its extensive use in ordinary hospitals and clinical laboratories. Using the traditional liquid chromatography method, the full separation of these metabolites in complex biological samples is still not achieved. In this study, an improved ultra-high-performance liquid chromatography with ultraviolet spectroscopy method was reported for quantitative determination of five gout-related metabolites (i.e., creatinine, uric acid, hypoxanthine, xanthine, and inosine) in human serum within 10min. A UHPLC system equipped with a hydrophilic C18 column was used to improve separation, shorten analysis time, and increase analysis throughput. The performance of the method was validated by evaluating linearity (squared correlation coefficient>0.9991), recovery (92.8-100.0%, with relative standard deviation<4.7%), accuracy (relative errors<14.6%), precision (0.2-4.1% for intraday and 2.1-7.3% for interday) and stability (-14.1 to 8.3% in autosampler for 12 h and -13.3 to 2.2% for freeze-thaw cycles). This method was successfully applied to quantify gout-related metabolites in serum samples of healthy controls and gout patients, which was expected to be used in the clinical investigation of gout at different stages.

Development and validation of a fast and simple HPLC method for the simultaneous determination of bisoprolol and enalapril in dosage form

Aim. We aimed to develop and validate fast, simple, accurate, robust and rugged chromatographic method for simultaneous determination of bisoprolol fumarate and enalaril maleate in solid pharmaceutical dosage form, with using chaotropic strong chaotropic perchlorate anions in composition of mobile phase. Materials and methods. Fast simple HPLC method for simultaneous determination of bisoprolol and enalapril in solid pharmaceutical dosage forms was developed, with perfect peak symmetries eluting at 4.7 and 5.2 miutes, with mobile phase composed of methanol and diluted perchloric acid pumped with 1ml/min on Zorbax Rx C8 250x4.6mm, 5um column thermostated at 42 °C, and monitored UV signal at 214nm. Mobile phase was composed of 55%methanol and 45% perchloric acid (0.07%v/v). Results. Usage of presence of perchloric anions showed very useful role in peak shape and chromatogram view, due to distinguished chaotropic characteristics of perchlorate anions on molecules containing nitrogen atoms in molecular structures of analytes, in acidic pH environment. Linearity was examined and proven at different concentration levels in the range of working concentration of bisoprolol (20–200 ug/ml) and enalapril (20–200 ug/ml). The methods achieved very good validation parameters, with determined LOQ about 0.032 mg/ml and LOD about 0.003 mg/ml for bisoprolol, and LOQ about 0.045 mg/ml and LOD 0.005 mg/ml for enalapril. The high value of recoveries obtained for bisoprolol and enalapril indicates that the proposed method was found to be accurate. Conclusion. A new fast and simple, but selective, accurate, precise and robust HPLC method for simultaneous determination of bisoprolol and enalapril in tablets was developed and many possible variations of the same were suggested. The developed method for the simultaneous quantification of bisoprolol and enalapril from solid dosage formulations offers simplicity essential for quality control of a large number of samples in short time intervals, which is necessary for routine analysis.

Validated ultra-performance chromatographic method for simultaneous determination of andrographolide and its four related diterpenoids in Andrographis paniculata capsules

Validated ultra-performance chromatographic method for simultaneous determination of andrographolide and its four related diterpenoids in Andrographis paniculata capsules

DEVELOPMENT AND METHODOLOGY FOR THE ESTIMATION OF LISINOPRIL AND ATORVASTATIN IN PHARMACEUTICALS

Introduction. The cause of hypertension and coronary heart disease in most cases is hypercholesterolemia. Therefore, for the treatment and prevention of most pharmacotherapy regimens, antiatherosclerotic drugs are used. With a high class of recommendations and level of evidence, high efficiency for primary and secondary prevention of coronary heart disease, statins are widely used in clinical practice.&#x0D; The aim of the study – to improve more rapid, simple, selective, less expensive methods of thin layer chromatography analysis of simultaneous determination of lisinopril and atorvastatin in pharmaceuticals.&#x0D; Research Methods. The present study assessed mobile phases of lisinopril and atorvastatin for TLC.&#x0D; Results and Discussion. Thin layer chromatography can be used to: monitor the progress of a reaction, identify compounds, determine the purity of a substance. Method of simultaneous identification of lisinopril and atorvastatin by TLC was developed. We investigated different mobile phases to optimize the development of analytical methods of lisinopril and atorvastatin by TLC. It was established that the most optimal Rf observed using mobile phase ammonia R (25 %) – propanol R (30:70, v/v). We explored the validation characteristics – specificity and suitability of the chromatographic system that met, the eligibility criteria established by the SPhU.&#x0D; Conclusions. We developed chromatographic method for simultaneous determination of lisinopril and atorvastatin. Propects for future research will be aimed at developing analytical methods of analysis.

A simple and economic chromatographic method for simultaneous determination of six bronchodilator drugs in pharmaceutical dosage forms

Chronic obstructive pulmonary disease is a major cause of morbidity and mortality worldwide. Combining an inhaled anticholinergic and a β2-agonist are a convenient way of delivering treatment, obtaining better lung function and improved symptoms. We aimed to develop and validate a reliable HPLC method for the simultaneous determination of the anticholinergics; ipratropium bromide, glycopyrronium bromide and tiotropium bromide in addition to the β2-agonists; bambuterol hydrochloride, formoterol fumarate and indacaterol maleate. The chromatographic separation was achieved on a Phenomenex Luna phenyl-hexyl (250 × 4.6 mm i.d., 5 μm) column and a mobile phase composed of 0.2% phosphoric acid (pH 3.0)/methanol/acetonitrile (66:12:22, v/v/v). The analysis was performed at a flow rate of 1 mL/min with UV detection at 210 nm. Method validation showed that calibration curves were linear within the range from 0.5 to 30.0 μg/mL with a correlation coefficient > 0.998. Intraday and interday precision and accuracy evaluated by relative standard deviation were lower than 2%. The limits of detection were in the ranges of 0.037–0.152 μg/mL. The developed method which is rapid, sensitive and highly efficient was applied for the analysis of the six bronchodilators in single and combined formulations saving money, solvents and chemicals. In addition, the environmental impact of the proposed method was evaluated using a suitable analytical Eco-Scale.

Validation of a simple ion chromatography method for simultaneous determination of glyphosate, aminomethylphosphonic acid and ions of Public Health concern in water intended for human consumption

The herbicide glyphosate and its main metabolite aminomethylphosphonic acid (AMPA) are generally studied in environmental samples in the investigation of contamination of soil, plants, water and food. Many analytical methods are based on liquid chromatography or high-performance liquid chromatography, with pre-column or post-column derivatization; in addition, the chromatograph can be coupled to mass spectrometers for detection and quantification. Gas chromatography and spectroscopic and electrochemical methods have also been used. In this work, a simple low-cost method is presented for the analysis of water intended for human consumption with the quantification not only of glyphosate and AMPA, but also of other ions of interest to public health (fluoride, chlorite, bromate, chloride, nitrite, nitrate, sulfate and phosphate). Based on ion chromatography with conductivity detection (chemical suppression of eluent conductivity), the key point in this method is the use of gradient elution with two eluents of different pH and ionic strength, not requiring derivatization. There is no interference from the other ions at higher concentrations. The detection limits obtained for glyphosate and AMPA were 15 μg L−1 and 80 μg L−1, respectively. As the method allows the analysis of a large number of samples, it has been successfully applied to monitoring the quality of tap water in 89 municipalities in the northeast region of the State of São Paulo, Brazil.

A novel stability-indicating analytical method development for simultaneous determination of carboplatin and decitabine from nanoparticles.

Drug resistance is one of the main problems of cancer treatment. For this reason, combination therapy is commonly used for years. The combination of a chemotherapeutic, carboplatin, and the epigenetic drug decitabine is a new approach to modulate drug resistance. Nanoparticulate systems can overcome the drawbacks associated with the drug combinations. An analytical method that can detect and quantify carboplatin and decitabine which is encapsulated into the nanoparticles is necessary for nanoparticle development. In the literature, there is no analytical method in which carboplatin and decitabine are determined simultaneously. The primary purpose of this study is to develop and validate a novel, and stability-indicating high-performance liquid chromatography method for simultaneous determination of carboplatin and decitabine in pharmaceutical preparations in addition to developing the first nanoformulation for this drug combination. Therefore, various experimental parameters were optimized. The chromatographic separation was achieved using an XSelect® CSH C18 (250 × 4.6 mm I.D., 5 µm) column and a mobile phase consisting of methanol:water (containing 0.1% phosphoric acid) (3:97, v/v). The mobile phase pH was adjusted to 7.0 with 5 M NaOH. The developed method was successfully applied for the simultaneous determination and quantification of carboplatin and decitabine co-encapsulated in nanoparticles and released into in vitro dissolution medium.

Simultaneous determination of complex cold medicine formulations by HPLC

A simple, rapid and reliable high performance liquid chromatographic method for simultaneous determination of compounds typically found in complex cold medicines (i.e. acetaminophen, bromvalerylurea, bucetin, caffeine, chlorpheniramine maleate, dextromethorphan HBr, ethoxybenzamide, guaifenesin, methylephedrine HCl, noscapine HCl) has been developed. Isocratic separation was performed using an Inertsil ODS-3V column (5 μm, 25 cm x 4.6 mm i.d.) with a mobile phase: 0.2% triethylamine, 2% tetrahydrofuran in 0.1% H3PO4: CH3CN (85: 15; pH=2.70), flow rate 1.0 ml/min. An ultraviolet spectrophotometer was used as the detector at the wavelength of 205 nm. The precision and accuracy were satisfactory. The system can be used to assay the above compounds at typical cold medicine dosage forms.

Simultaneous determination of sulfa drugs and tetracyclines in feeds and animal tissues by high-performance liquid chromatography

This study aimed to develop a high-performance liquid chromatographic method for simultaneous determination of six sulfa drugs, three tetracyclines antibiotics and carbadox in feeds and animal tissues. Four successful conditions were established: 1. On LiChrosorb RP-C18 column with water: acetonitrile (95:5, v/v) s mobile phase and UV detector at 254 nm to separate SDA, SMM, STA, SDM, SMT and SQO. 2. On ultrasphere ODS Column with water: acetonitrile (85:15, v/v) as mobile phase and detected at UV 254 nm to separate SDA, SMM, STA, SMT, SQO and SDM. 3. On LiChrosorb RP-C18 column with water: isopropanol (93:7, v/v) as mobile phase and detected at UV 254 nm to separate STA, SMT, Carbadox, TC, OTC and CTC. 4. On Alltech RP-C18 column with water: dimethylformamide (72:28, v/v) as mobile phase and detected at UV 280 nm to separate STA, SMT, OTC, Carbadox and CTC. The recoveries of the drugs in feeds were between 85-99%; in animal tissues, 69-80%. Eleven out of 20 feed samples were found with prohibited sulfa drugs or tetracyclines added. One pork sample with OTC residue and two pig liver samples with total sulfa drugs residue exceeding the maximum tolerance limits were detected from the 21 meat samples analyzed. The lowest detection limits of residual drugs were between 1.0 - 5.0 ppb in feeds; 2.0 - 12 ppb in animal tissues.