Simultaneous determination of methotrexate and metoclopramide in physiological fluids using RP-HPLC with ultra-violet detection; application in evaluation of polymeric nanoparticles

Methotrexate (MTX) is an anticancer drug while metoclopramide (MCP) is an antiemetic agent. Both the drugs are commonly coprescribed to avoid the emesis caused by anticancer drug. In this study, a novel, rapid, sensitive, and cost-effective reverse-phase high-performance liquid chromatography method was developed and validated for simultaneous determination of the methotrexate and metoclopramide in biological and pharmaceutical samples using sparfloxacin as internal standard. The analytes were separated on a Kromasil 100-5C18 RP (250?×?4.6?mm, 5?µm) column, methanol, and 0.05% trifloroacetic acid (36:64?v/v) as mobile phase with a flow rate of 1?mL/min, detection wavelength of 290?nm, and column oven temperature at 40°C. Both the analytes were extracted from physiological fluids (bovine aqueous humor, vitreous humor, and human plasma) using mixture of methanol and 10% perchloric acid (50:50 v/v). The method was linear over the concentration range of 0.025–1.0?µg/mL for methotrexate and 0.030–1.0?µg/mL for metoclopramide. The % recovery from human plasma was 98.57 and 96.74% for MTX and MCP, respectively, while from aqueous humor and vitreous humor was 95.84 and 98.51% for MTX.

The developed method was applied for in vitro release of MTX from polymeric nanoparticles and can be applied for analysis of pharmaceutical and biological samples containing both the drugs.     

Validated HPTLC and HPLC methods for determination of fluorometholone and sodium cromoglycate in presence of their impurities and degradation products; application to kinetic study and on rabbit aqueous humor

Fluorometholone (FLM) and Sodium Cromoglycate (CMG) are co-formulated in ophthalmic preparation and showed marked instability under different conditions. Two specific, sensitive and precise stability-indicating chromatographic methods have been developed and validated for their determination in the presence of their degradation products and FLM impurity. Ten components were efficiently separated by them. The first method was HPTLC-spectrodensitometry, where the separation was achieved using silica gel 60?F₂₅₄ HPTLC plates and developing system of ethyl acetate: methanol (9:1, v/v). The second method was a reversed phase HPLC associated with kinetic study of the degradation process and was successfully applied for determination of the studied compounds in spiked rabbit aqueous humor. The mobile phase was acetonitrile: methanol: 0.05?M potassium dihydrogenphosphate (0.1% trimethylamine); pH 2.5, adjusted with orthophosphoric acid (20: 30: 50, by volume). In both methods, the separated components were detected at 240?nm and system suitability was checked. Good correlation was obtained in the range of 0.10–24.00 and 0.20–48.00?µg band^?1, for FLM and CMG by HPTLC. While for HPLC, the linearity ranges from 0.01–50.00 and 0.05–50.00?µg?mL^?1 for both drugs. The methods were applied in pharmaceutical formulation, where they were compared to the reported method with no significant difference.     

Biocompatible APTES–PEG Modified Magnetite Nanoparticles: Effective Carriers of Antineoplastic Agents to Ovarian Cancer

Magnetite nanoparticles are particularly attractive for drug delivery applications because of their size-dependent superparamagnetism, low toxicity, and biocompatibility with cells and tissues. Surface modification of iron oxide nanoparticles with biocompatible polymers is potentially beneficial to prepare biodegradable nanocomposite-based drug delivery agents for in vivo and in vitro applications. In the present study, the bare (10 nm) and polyethylene glycol (PEG)–(3-aminopropyl)triethoxysilane (APTES) (PA) modified (17 nm) superparamagnetic iron oxide nanoparticles (SPIO NPs) were synthesized by coprecipitation method. The anticancer drugs, doxorubicin (DOX) and paclitaxel (PTX), were separately encapsulated into the synthesized polymeric nanocomposites for localized targeting of human ovarian cancer in vitro. Surface morphology analysis by scanning electron microscopy showed a slight increase in particle size (27?±?0.7 and 30?±?0.45 nm) with drug loading capacities of 70 and 61.5 % and release capabilities of 90 and 93 % for the DOX- and PTX-AP-SPIO NPs, respectively (p?<?0.001). Ten milligrams/milliliter DOX- and PTX-loaded AP-SPIO NPs caused a significant amount of cytotoxicity and downregulation of antiapoptotic proteins, as compared with same amounts of free drugs (p?<?0.001). In vivo antiproliferative effect of present formulation on immunodeficient female Balb/c mice showed ovarian tumor shrinkage from 2,920 to 143 mm³ after 40 days. The present formulation of APTES–PEG-SPIO-based nanocomposite system of targeted drug delivery proved to be effective enough in order to treat deadly solid tumor of ovarian cancer in vitro and in vivo.     

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.     

Simultaneous CE Determination of Captopril and Indapamide in Pharmaceuticals and Human Plasma

Capillary electrophoresis with UV photo diode-array detection was utilized to adopt a new method for the assay of captopril and indapamide in pharmaceuticals and human plasma. Electrophoretic conditions controlling the analysis were optimized to develop separation, sensitivity and rapidity. The optimum conditions obtained were 100 mM borate at pH 9.0, injection time 10.0 s, voltage 25 kV and column temperature 25 °C with detection at 220 nm. Relatively, wide dynamic ranges for captopril (1–100 mg L^?1) and indapamide (0.1–40 mg L^?1) were obtained. Also, the method recorded acceptable intra- and inter-day accuracy (89.8–97.9%) and precision (0.77–3.50%) in pharmaceutical formulations and human plasma. The sensitivity of the method was developed by the optimization and the preconcentration conducted for human plasma sample using liquid–liquid extraction. The limit of detection gained (0.075 and 0.045 mg L^?1 for captopril and indapamide, respectively) reached the level of both drugs possibly found in human plasma. The method is suitable to be applied in pharmaceutical industries for quality control and in clinical laboratories for therapeutic drug monitoring purposes.     

Validated UPLC method for the determination of guaiphenesin,oxeladin citrate,diphenhydramine, and sodium benzoate in their quaternary mixture used in treatment of cough,in the presence of guaiphenesin-related substance (guaiacol)

Accurate, precise, and sensitive UPLC method was developed and validated for the simultaneous determination of a quaternary mixture containing guaiphenesin (GUP), oxeladin citrate (OXC), diphenhydramine (DPH), and sodium benzoate (SOB) in the presence of GUP-related substance, guaiacol (GUA). Chromatographic separation was achieved using NUCLEOSHELL^® column—C₁₈ (4.0?×?50.0 mm, 2.7 μm). Isocratic elution at a flow rate 1.0 mL/min was performed using a mobile phase consisting of acetonitrile:phosphate buffer pH 3.5?±?0.1 (25.0:75.0, v/v). The specificity of the developed method was investigated by analyzing of laboratory-prepared mixtures containing different ratios of the four drugs, in the presence of GUA as well as their combined pharmaceutical formulation. The obtained results were statistically compared with those obtained by the official or reported methods, showing no significant difference with respect to accuracy and precision at p?=?0.05.     

Electrochemical reduction of ciprofloxacin at the mercury electrode and its voltammetric determination in tablet and urine

In this study a reduction square wave voltammetric method was developed and validated for the direct determination of ciprofloxacin (CIP) in pharmaceutical formulation and biological fluid using hanging mercury dropping electrode (HMDE) surface. Best results were obtained for the quantitative determination of CIP in 0.02 M Britton-Robinson buffer at pH 2.5 and at a potential of ?1300 mV vs. Ag/AgCl reference electrode. Various experimental and instrumental parameters affecting the peak current and potential of CIP electrochemical reduction were investigated and optimized. The monitored peak current was directly proportional to the concentration of CIP, where it exhibited a linear response in the range 3.0 × 10^?7–2 × 10^?6 M (r = 0.99). The accuracy of the proposed method was concluded based on the value of mean recovery of 98 ± 0.72 % with RSD of 0.181 % at a detection limit of 7 × 10^?9 M. Possible interferences by various substances usually present in pharmaceutical formulations have been also evaluated. After validating the proposed method, the applicability of this voltammetric method was demonstrated by estimating CIP in its pharmaceutical formulation and spiked human urine, where values of mean recoveries of 97 ± 1.0% and 108.0 ± 2.0% were obtained, respectively.     

LC Determination of Ketorolac in Human Plasma and Urine for Application to Pharmacokinetic Studies

A simple, specific and sensitive liquid chromatographic method has been developed for the assay of ketorolac in human plasma and urine. The clean-up of plasma and urine samples were carried out by protein precipitation procedure and liquid–liquid extraction, respectively. Separation was performed by a Waters sunfire C₁₈ reversed-phase column maintained at 35 °C. The mobile phase was a mixture of 0.02 M phosphate buffer (pH adjusted to 4.5 for plasma samples and to 3.5 for urine samples) and acetonitrile (70:30, v/v) at a flow rate of 1.0 mL min^?1. The UV detector was set at 315 nm. Nevirapine was used as an internal standard in the assay of urine sample. The method was validated over the concentration range of 0.05–8 and 0.1–10 μg mL^?1 for ketorolac in human plasma and urine, respectively. The limits of detection were 0.02 and 0.04 μg mL^?1 for plasma and urine estimation at a signal-to-noise ratio of 3. The limits of quantification were 0.05 and 0.1 μg mL^?1 for plasma and urine, respectively. The extraction recoveries were found to be 99.3 ± 4.2 and 80.3 ± 3.7% for plasma and urine, respectively. The intra-day and inter-day standard deviations were less than 0.5. The method indicated good performance in terms of specificity, linearity, detection and quantification limits, precision and accuracy. This assay demonstrated to be applicable for clinical pharmacokinetic studies.     

Determination of Tectorigenin in Rat Plasma: Application to a Pharmacokinetic Study After Oral Administration of Tectorigenin or Its Prodrug Tectoridin

A simple, sensitive, and validated liquid chromatographic method has been developed for the determination of tectorigenin in rat plasma and application to a pharmacokinetic study after oral administration of tectorigenin or its prodrug tectoridin. The analysis was performed on a Kromasil C₁₈ analytical column using gradient elution with acetonitrile 0.1% phosphonic acid water at 0.8 mL min^?1. The detection wavelength for UV detection was set at 264 nm. The established method was fully validated with parameters as follows: the intra- and inter-day assay precisions (CV) of three analytes were in the range of 4.2–13.3% and accuracies were between 98.0 and 107.5%; the calibration curve was linear with r ² > 0.99 over a concentration range of 0.02–2 μg mL^?1; the lower limit of quantification was 0.02 μg mL^?1; tectorigenin showed stable in rat plasma after 12 h incubation at room temperature, 15 days storage at ?80 °C and three freeze/thaw cycles, as well as in reconstitute buffer for 24 h at 25 °C; and the mean recoveries of tectorigenin were 92.3 ± 3.2, 95.5 ± 2.9 and 94.5 ± 3.0% with quality control levels of 0.02, 0.2 and 2 μg mL^?1, respectively. In conclusion, this method is simple, economic, and sensitive enough for in vivo pharmacokinetic studies of tectorigenin.     

CZE Separation of New Drugs for Treatment of Leukemia

Imatinib, bosutinib, dasatinib, pazopanib, erlotinib, canertinib and vatalanib are new developed anticancer drugs, especially for treatment of leukemia. In this article, a fast and high throughput capillary zone electrophoresis method has been developed and validated for analysis of these new drugs in pharmaceutical formulas. The method can be easily utilized for determination of all the drugs in one run what is advantageous for the quality control in pharmaceutical industry because there is no need for changing and optimization of separation conditions when changing the analyte. The separation was performed using an uncoated fused silica capillary with 100 mmol L^?1 sodium phosphate buffer pH 2.75, voltage of 25 kV, hydrodynamic injection time of 5 s by 50 mbar, and detection at 214 nm. Under these conditions, the analysis took about 8 min. The validation of all the drugs resulted in recoveries in the range of 84–100 %. The method showed to be precise for all the drugs with RSDs of migration times lower than 0.9 % (interday precision). A very good linearity in the validated range (5–100 μg mL^?1) and the limits of detection (LODs) in the range of 0.5–2.0 (μg mL^?1) were achieved. Finally, we proved that the method is robust by the Youden’s test. Therefore, our method can be successfully applied for analysis of the real pharmaceutical samples.     

Spectrophotometric determination of metronidazole in pharmaceutical pure and dosage forms using p-benzoquinone

A simple and accurate spectrophotometric method for the determination of metronidazole in pure and pharmaceutical dosage forms has been developed. The proposed method is based on the reduction of the nitro group to amino group of the drug. This can be achieved by heating a mixture of an alcoholic solution of metronidazole, zinc powder and dilute hydrochloric acid in a water bath at 90 ± 5 °C for 15 min. The cold and clear filtrate reacts with p-benzoquinone to develop a purple color, which absorbs maximally at 526 nm. The calibration graph is linear over the concentration range of 15–190 μg ml^?1 with a molar absorptivity of 1.09 × 10³ l mol^?1 cm^?1. The proposed method is applied to commercially available pharmaceutical dosage forms and the results are statistically compared with those obtained by the reference method.     

Studies on reaction of reduced lipoic acid with Mukaiyama reagent and its application for pharmaceutical and food analysis

A new sensitive method for the determination of lipoic acid (LA) in selected food items based on its reaction with Mukaiyama reagent (2-chloro-1-methylpyridinium iodide, CMPI) was developed. It was stated that CMPI reacts with reduced form of lipoic acid (dihydrolipoic acid, DHLA) and the stable product is produced. The spectrum of the labeled form of DHLA exhibits new band at 312?nm. Based on its spectral characteristics new spectrophotometric and UV–high-performance liquid chromatography (HPLC) methods of LA determination were elaborated. Both methods allowed determination of the analyte in the concentration range of 5?×?10^?6–1?×?10^?4?mol?L^?1 with limit of detection 0.39?×?10^?6 and 0.77?×?10^?6?mol?L^?1 for spectrophotometric and HPLC method, respectively. The practical usability of newly developed methods was checked by determination of lipoic acid contents in its pharmaceutical preparate Revitanerw. The proposed method was precise and accurate. The relative error of determination did not exceed ±0.067%. As chromatographic method allowed the determination of analyte in the presence of complex matrix, it was applied for assay of free fraction of α-lipoic acid in selected food items. A procedure of LA isolation from biological matrix was developed. The extraction with dichloromethane allowed quantitative recovery at 102.94?±?4.20%. The green barley appeared to be the richest source of LA.     

Determination of Nateglinide in Human Plasma by LC-ESI-MS and Its Application to Bioequivalence Study

To evaluate the bioequivalence of nateglinide, a rapid and specific liquid chromatographic-electrospray ionization mass spectrometric method was developed and validated to determine nateglinide for human plasma samples. The analyte was detected using electrospray positive ionization mass spectrometry in the selected ion monitoring mode. Tinidazole was used as the internal standard. A good linear relationship obtained in the concentration ranged from 0.05 to 16 μg mL^?1 (r ² = 0.9993). Lower limit of quantification was 0.05 μg mL^?1 using 100 μL of plasma sample. Intra- and inter-day relative standard deviations were 2.1–7.5 and 4.7–8.9%, respectively. Among the pharmacokinetic data obtained, T _max was 2.09 ± 1.06 h for reference formulation and 2.40 ± 0.97 h for test formulation. C _max was 4.17 ± 1.31 μg mL^?1 for reference formulation and 4.37 ± 1.53 μg mL^?1 for test formulation. The half-life (t _½) was 1.93 ± 0.44 h for reference formulation and 1.92 ± 0.29 h for test formulation. AUC_0–10h was 13.67 ± 4.36 μg h mL^?1 for reference formulation and 13.21 ± 4.09 μg h mL^?1 for test formulation. This method was successfully applied to the pharmacokinetic study in human plasma samples.     

Development and validation of a RP-HPLC method for simultaneous quantification of bedaquiline (TMC207), moxifloxacin and pyrazinamide in a pharmaceutical powder formulation for inhalation

A reversed phase high performance liquid chromatography (RP-HPLC) method for the simultaneous quantification of bedaquiline (TMC207), moxifloxacin and pyrazinamide in a pharmaceutical powder formulation for inhalation has been developed and validated. The powder was simply dissolved in methanol and the analytes separated in a run time of 20?min on a Luna C18 (2) (150?×?4.6?mm, 5?µm) column using gradient elution with methanol and triethylamine phosphate buffer (pH 2.5) delivered at 1.2?mL/min. The detection (with retention time) was carried out at 269?nm (2.9?min) for pyrazinamide, 296?nm (7.0?min) for moxifloxacin and 225?nm (16.3?min) for bedaquiline, respectively. The method was linear for all analytes in the concentration range 1-100?µg/mL with correlation coefficients >0.998. Lower limits of quantitation (µg/mL) of bedaquiline, moxifloxacin and pyrazinamide were 0.56, 0.43 and 0.24, respectively. The method was accurate (relative error in the range ?0.2 to 2.2) and precise (%RSD ≤6.2) with recovery in the range 100.0–104.7%. The method was successfully applied to determine the drug content and content uniformity of the three analytes in a spray-dried combination powder formulation for inhalation containing L-leucine.     

New Spectrophotmetric Methods for Determination of Cephapirine Na

Three sensitive and accurate spectrophotometric procedures were developed for the analysis of cephapirine sodium in pure form and in its pharmaceutical formulation. Method A: A kinetic method based on the observation that in acidic medium cephapirine reduces sodium molybdate to molybdenum blue, the absorbance of which is proportional to the amount of antibiotic present at a fixed time of 40 minutes; the formed product was spectrophotometrically measured at 780 nm. The concentration of drug calculated using its calibration by fixed concentration and rate constant methods is feasible with the calibration equations obtained, but the fixed time method proved to be more applicable. Method B is based on chetale formation with palladium(II) chloride in buffered medium as the interaction between metal ions and ligand anions or moleules capable of the formation of complexes which results in the development of colors suitable for the characterization of quantitative determination of metal or ligand. Metals containing easily excited d or f electrons were suitable for the formation of colored complexes. Method C, is based on the formation of colored complex between palladium(II), eosin and cephapirine Na. Sodium lauryl sulphate is used as surfactant to increase the solubility and intensity of the formed complex. Under optimum conditions, the complexes showed maximum absorption at Δ370 and Δ550 for methods B and C, respectively. Apparent molar absorpitivities were 5.2 × 10³, 5.5 × 10³, 1.4 × 10⁴; Sandell's sensitivities were 1.17 × 10^?3, 1.24 × 10^?3, 3.1 × 10^?3, for methods A, B and C, respectively. The solution of the products obeyed Beer's Law in the concentration ranges 10–70, 20–70, 2–48, μg mL^?1 for methods A, B, and C. The proposed methods were applied to the determination of the drug in pure or pharmaceutical preparations. The results obtained were compared statistically with those given by the official method.     

Spectrofluorimetric Determination of Itraconazole in Dosage Forms and Spiked Human Plasma

A highly sensitive fluorimetric method was developed for the determination of itraconazole in pharmaceutical preparations and biological fluids. The proposed method is based on measuring the native fluorescence intensity of itraconazole in methanol at 380 nm after excitation at 260 nm. The fluorescence intensity‐concentration plot was rectilinear over the range 0.2 to 2.0 μg/mL with a lower detection limit of 0.05 μg/mL (6.52 × 10^?11 M). The method was further applied to the determination of itraconazole in capsules and spiked human plasma, the mean % recoveries (n = 4) was 100.37 ± 0.86 and 95.47 ± 2.93, respectively. The mean % recoveries were in agreement with those obtained from a reference method.     

HPLC Analysis and Pharmacokinetic Study of Paeoniflorin after Intravenous Administration of a New Frozen Dry Powder Formulation in Rats

A simple and specific high performance liquid chromatographic (HPLC) method with UV detection using picroside II as the internal standard was developed and validated to determine the concentration of paeoniflorin in rat plasma and study its pharmacokinetics after an single intravenous administration of 40 mg kg^?1 paeoniflorin to Wistar rats. The analytes of interest were extracted from rat plasma samples by ethyl acetate after acidification with 0.05 mol L^?1 NaH₂PO₄ solution (pH 5.0). Chromatographic separation was achieved on an Agilent XDB C₁₈ column (250 × 4.6 mm I.D., 5 μm) with a Shim-pack GVP-ODS C₁₈ guard column (10 × 4.6 mm I.D., 5 μm) using a mobile phase consisting of acetonitrile–water–acetic acid (18:82:0.4, v/v/v) at a flow rate of 1.0 mL min^?1. The UV detection was performed at a wavelength of 230 nm. The linear calibration curves were obtained in the concentration range of 0.05–200.0 μg mL^?1 in rat plasma with the lower limit of quantification (LLOQ) of 0.05 μg mL^?1. The intra- and inter-day precisions in terms of % relative standard deviation (RSD) were lower than 5.7 and 8.2% in rat plasma, respectively. The accuracy in terms of % relative error (RE) ranged from ?1.9 to 2.6% in rat plasma. The extraction recoveries of paeoniflorin and picroside II were calculated to be 69.7 and 56.9%, respectively. This validated method was successfully applied to the pharmacokinetic study of a new paeoniflorin frozen dry power formulation. After single intravenous administration, the main pharmacokinetic parameters t _1/2, AUC_0-∞, CL_TOT, V _Z, MRT_0-∞ and V _ss were 0.739 ± 0.232 h, 43.75 ± 6.90 μg h mL^?1, 15.50 ± 2.46 L kg^?1 h^?1, 1.003 ± 0.401 L kg^?1, 0.480 ± 0.055 h and 0.444 ± 0.060 L kg^?1, respectively.     

Determination of Dydrogesterone in Human Plasma by Tandem Mass Spectrometry: Application to Therapeutic Drug Monitoring of Dydrogesterone in Gynecological Disorders

A sensitive and specific tandem mass spectrometric (MS–MS) method was developed and validated for the determination of dydrogesterone (Duphaston^®), an orally active synthetic progestogen, in human plasma. Multiple reaction monitoring (MRM) scans at m/z 313.1 > 105.5 (dydrogesterone) and m/z 393 > 147 (dexamethasone, internal standard) were selected to determine dydrogesterone by the internal standard method. Linear correlations (r: ～0.99 ± 0.05) of the calibration curves were established over the concentration range 10–60 ng mL^?1 with a lower limit of quantification (LLQ) of 10 ng mL^?1 (RSD% 14.9 and %DEVs ?10.5 to +15.6). Solid-phase extraction (SPE) technique was used for extraction of dydrogesterone and internal standard from patient plasma samples using Oasis^® Max C18 cartridges. Ion suppression studies indicated negligible effects of plasma matrix on the mass ions detection of dydrogesterone and IS, when measured in MRM mode. Validation data showed that RSD% values were <22.0%, whereas %DEV values were in the range of ?20.2 to +13.3 for intra- and inter-day precision and accuracy, respectively. Analytical recoveries of dydrogesterone from supplemented plasma samples with the drug were in the range of 100.7–112%, indicating the efficiency of the SPE for separation of dydrogesterone from human plasma. Stability studies conducted at ?20 °C, showed that dydrogesterone was stable in plasma as indicated from the measured degradation kinetic parameters. The developed method was applied for monitoring plasma levels of dydrogesterone in 25 patients treated with Duphaston^® tablets at a dose of 10 mg three times daily. Mean plasma concentration of 16.1 ± 3.5 ng mL^?1 of dydrogesterone were measured at the steady state. The data suggest the utility of tandem mass method in therapeutic drug monitoring of plasma levels of dydrogesterone in gynecological disorders treated with Duphaston^® tablets.     

Bioequivalence evaluation of Florfenicol pharmaceutics in pigs using liquid chromatography-tandem mass spectrometry

The bioequivalence of two Florfenicol (FF) products in pigs was evaluated. A 2?×?2 crossover trial with a 14 days wash-out period was performed. The pigs were orally administered in a single dose (2?mg/kg b.w of FF). Serum samples were analyzed using a liquid chromatography-tandem mass spectrometry method. The limit of quantification was 0.1?ng/mL, and the calibration range was 1.0–100.0?ng/mL. Furthermore, intraday and interday were 5.43–9.09% and 6.23–9.68%, respectively. The areas under the curve (AUC_0–48) for the test product B of FF and reference product A were 7289.61?±?1750.44 and 6545.01?±?2766.25?h?×?ng/mL, respectively. The highest concentrations of FF in the serum (C_max) were 726.05?±?211.77 and 641.97?±?117.94?ng/mL. The mean retention times (MRT) was 7.91?±?1.98 and 7.76?±?2.89?h while the half-lives (T_1/2) were 4.07?±?1.71 and 4.99?±?3.30?h. From the analysis of variance results, the p values of C_max and AUC_0–∞ for the 90% confidence interval were 0.492 and 0.320 (p?>?0.05), respectively. A comparison between the test product and the reference product showed no significant difference. Both products showed bioequivalence after being administered in pigs.     

A simple spectrophotometric procedure for the determination of antimony (III) and (V) in antileishmanial drugs

A spectrophotometric method for the selective determination of antimony (III) and (V) in antileishmanial drugs is described. The procedure is based on the reaction of Sb(III) with bromopyrogallol red (BPR) in neutral solution. As a consequence of the Sb-BPR complex formed, the absorbance of BPR, at 560 nm, decreases proportionally to the amount of Sb(III) in the analyte solution. The calculated apparent molar absorptivity and determination limits are 3.67 × 10⁴ L?·?cm^–1?·?mol^–1 and 1.65 × 10^–6 mol/L, respectively. Sb(V) is determined after reduction to Sb(III) by iodide. The Sb(V) content determined in ten samples of Glucantime varied from 75.40 ± 0.97 to 94.47 ± 1.0 mg/mL. Sb(III) was detected in all samples analyzed, and mean values ranged from 5.19 ± 0.16 to 10.52 ± 0.15 mg/mL. The method is suitable for the routine quality control of pharmaceutical formulations.