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.

     

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 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 Stability-Indicating LC Method for Simultaneous Analysis of Aceclofenac and Paracetamol in Conventional Tablets and in Microsphere Formulations

A stability-indicating reversed-phase LC method for analysis of aceclofenac and paracetamol in tablets and in microsphere formulations has been developed and validated. The mobile phase was 80:20 (v/v) methanol–phosphate buffer (10 mM at pH 2.5 ± 0.02). UV detection was at 276 nm. The method was linear over the concentration ranges 16–24 and 80–120 μg mL^?1 for aceclofenac and paracetamol, respectively, with recovery in the range 100.9–102.22%. The limits of detection and quantitation for ACF were 0.0369 and 0.1120 μg mL^?1, respectively; those for PCM were 0.0631 and 0.1911 μg mL^?1, respectively.     

Analysis of Pazufloxacin Mesilate in Human Plasma and Urine by LC with Fluorescence and UV Detection,and Its Application to Pharmacokinetic Study

A liquid chromatographic method for analysis of pazufloxacin mesilate in human plasma and urine has been developed and validated for selectivity, sensitivity, accuracy, precision, and stability in pharmacokinetic analysis. The sensitivity of the method was 0.02 μg mL^?1 in plasma and 0.5 μg mL^?1 in urine, with overall intra-day and inter-day precision (RSD < 10%) and accuracy (90–120%) acceptable for clinical pharmacokinetic analysis. Recovery from plasma and urine was 80–110% for both pazufloxacin mesilate and enoxacin, the internal standard. Pazufloxacin was stable in both plasma and urine, with no significant degradation under four different conditions. The method was successfully used in a preliminary study of the bioavailability of pazufloxacin mesilate in healthy human volunteers after intravenous administration of 300 and 500 mg.     

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.

     

A Stability-Indicating Assay of Brimonidine Tartrate Ophthalmic Solution and Stress Testing Using HILIC

A stability-indicating hydrophilic interaction liquid chromatography (HILIC) method has been developed and validated for the quantitative determination of Brimonidine tartrate (BT) formulated as an ophthalmic solution. Isocratic separation was achieved using an acetonitrile-buffer mixture (92:8, v/v) at pH 7.1 on an unmodified silica column (250 × 4.6 mm, 5 μm). The drug was subjected to oxidative, hydrolytic, photolytic and thermal stress conditions and complete separation was achieved for the parent compound and degradation products. The influence of acetonitrile, pH and ionic strength of the buffer was studied. Linearity range and recoveries for BT were 100–400 μg mL^?1 and 100.12%, respectively. The method was validated for BT and indicated that the method was sufficiently sensitive with a limit of detection at 0.005 μg mL^?1 and a limit of quantitation at 0.02 μg mL^?1, respectively.     

The Pharmacokinetic Profiles of Pre-Operative Prophylactic Cefepime Application in Pregnant and Non-Pregnant Women Undergoing Surgical Interventions Using a Fully Validated Liquid Chromatographic Method

Pregnancy alters pharmacokinetic profile of many drugs, because of altering body volume and metabolism rate. Therefore, dosage rates and concentrations of drugs must be controlled during pregnancy. Here, we identified the pharmacokinetic profile of pre-operatively given cefepime in caesarean section and gynecological operations using a simple, rapid, cost-effective and valid liquid chromatographic method. The chromatographic separation was performed using 40 mM, pH 3.2 phosphate buffer containing 6 % methanol as mobile phase at 0.30 mL min^?1 flow rate. Gradient elution with methanol was applied to get shorter analysis time without any interference from plasma endogens. During analyses, temperature of column, autosampler and detector were set as 30, 10 and 40 °C, respectively. The detection wavelength was 260 nm and ceftizoxime was used as internal standard. At the optimum conditions, the cefepime analysis from plasma samples was completed in 7 min. Cefepime was extracted from plasma samples using perchloric acid with a very high recovery rate (99.3 %). The method was fully validated according to the Food and Drug Administration guidelines for bioanalytical method validation, and found to be selective, linear, repeatable, reproducible and robust. After validation studies, the method was applied to five caesarean-sectioned and four non-pregnant sectioned women treated with pre-operative, prophylactic single intravenous dose of cefepime (1 g Maxipime^®) in order to determine pharmacokinetic profile of cefepime. Peak serum concentrations of cefepime in caesarean-sectioned women at the arterial port after infusion was 70.11 ± 10.74 μg mL^?1. The mean elimination half-life, volume of distribution and calculated area under the concentration–time curve (AUC)_0–∞ were 1.10 ± 0.23 h, 14.22 ± 2.29 L and 101.55 ± 10.99 μg h mL^?1 for caesarean-sectioned women; and 1.14 ± 0.21 h, 14.76 ± 2.92 L and 104.71 ± 36.34 μg h mL^?1 for non-pregnant sectioned women, respectively. The area under curve, elimination half-life, maximum plasma concentration and the mean distribution volume of cefepime were not changed in case of pregnancy.     

A Simple Stability Indicating CZE Method for the Analysis of Octreotide Acetate

A simple stability indicating capillary zone electrophoretic method was developed and validated for the analysis of octreotide acetate (OCT-Ac). The best separation was achieved by bare fused silica capillaries (50 μm i.d.; 65.5 cm total and 57.0 cm effective length), phosphate buffer (pH = 3.25; 50 mM), at 32.5 °C. The samples were injected using 50 mbar for 5 s and subjected to the applied voltage of 27.5 kV for separation. The detection was carried out using a PAD at a wavelength of 195 nm. For improving the repeatability of the method, l-histidine was applied as an internal standard. According to the validation results, the method was linear in the concentration range of 3.30–400 μg mL^?1 (correlation coefficient of 0.9996) with a limit of detection of 1.08 μg mL^?1 and a limit of quantification of 3.30 μg mL^?1; accuracy of the method was between 100.4 ± 0.2 and 101.1 ± 0.2 %; intra-assay precision was 0.5–2.6 % and intermediate precision was 1.3–3.2 %. The proposed method was successfully applied for the quantification of OCT-Ac in both a pharmaceutical formulation and force-degraded samples and for the detection and separation of degradation products; besides, the obtained results were used for the evaluation of the degradation kinetics of OCT-Ac under different stress conditions. So, it is concluded that the developed method could be employed as a simple, accurate and precise stability-indicating method in quality control laboratories to assess the quantity and stability of OCT-Ac pharmaceutical products.     

Development and Validation of an LC Method for Simultaneous Determination of Ascorbic Acid and Three Phenolic Acids in Sustained Release Tablets at Single Wavelength

A simple, rapid and sensitive column liquid chromatographic method was developed and validated to measure simultaneously the amount of ascorbic acid and phenolic acids at single wavelength (240 nm) in order to assess drug release profiles and drug-excipients compatibility studies for a new sustained release tablet formulation and its subsequent stability studies. A combined isocratic and linear gradient reversed-phase LC method was carried out at 240 nm. Quantification was achieved with reference to the external standards. The linearity for concentrations between 0.042 and 0.150 mg mL^?1 for ascorbic acid, 0.084–0.250 mg mL^?1 for chlorogenic acid, 0.053–0.360 mg mL^?1 for caffeic acid, and 0.016–0.250 mg mL^?1 for ferulic acid (r > 0.99 for all analytes) were established. The recovery of the active ingredients from the samples was at the range of 92.3–102.9%. Intra- and inter-day precisions were less than 2.5%. The limits of detection and quantification were 8 and 24 μg mL^?1 for ascorbic acid, 18 and 54 μg mL^?1 for chlorogenic acid, 37 and 112 μg mL^?1 for caffeic acid, and 11 and 34 μg mL^?1 for ferulic acid. The determination of the four active ingredients was not interfered by the excipients of the products. Samples were stable in the release mediums (37 °C) at least for 12 h.     

Gas Chromatographic Determination of Guanidino Compounds Using Hexafluoroacetylacetone and Ethyl Chloroformate as Derivatizing Reagents

Guanidino compounds guanidine, methylguanidine, guanidinoacetic acid, guanidinobutyric acid, guanidinopropionic acid, and guanidinosuccinic acid after derivatization with hexafluoroacetylacetone and ethyl chloroformate at pH 9 in aqueous phase, eluted, and separated from gas chromatographic column HP-5 (30 m × 0.32 mm id) with film thickness of 0.25 μm at an initial column temperature 90 °C for 2 min, followed by heating rate of 10 °C min^?1 up to 220 °C with nitrogen flow rate of 1 mL min^?1. The detection was by flame ionization detector. The linear calibration ranges of each of guanidino compounds were obtained within 1–10 μg mL^?1, and the limit of detection was within 0.014–0.19 μg mL^?1. The derivatization and gas chromatography elution and separation were repeatable in terms of retention time and peak height/peak area with relative standard deviation (RSD) (n = 4) within 1.7–2.9 % and 1.4–2.8 %, respectively. The method was applied for the determination of guanidino compounds from deproteinized serum of uremic patients and healthy volunteers, and was found in the range below the limit of quantitation (BLOQ) to 1.25 μg mL^?1 with RSD within 1.4–3.6 %, and BLOQ to 0.4 μg mL^?1 with RSD 1.3–3.4 %, respectively. A number of pharmaceutical additives did not effect the determination with RSD within ±3.1 %.     

Simultaneous Determination of Clobetasol Propionate and Calcipotriol in a Novel Fixed Dose Emulgel Formulation by LC-UV

A new, rapid, selective, cheap and simple RP-LC method has been developed and validated for the simultaneous determination of clobetasol propionate and calcipotriol mixtures in bulk drugs (raw materials) and in a novel-fixed dose emulgel formulation. Separation was carried out using a NovaPak C18 column with methanol:water (74:26 v/v) as mobile phase for isocratic elution at a flow rate of 1.0 mL min^?1. The column temperature was set at 25 °C. Calibration curves were established ranging between 0.5 and 20 μg mL^?1 and 0.5 and 10 μg mL^?1 for clobetasol propionate and calcipotriol, respectively. Limit of detection and limit of quantification values of the method was found as 0.16 and 0.48 μg mL^?1 for clobetasol propionate and 0.10 and 0.30 μg mL^?1 for calcipotriol, respectively. The method was validated in accordance with ICH guidelines and obtained results proved that the proposed method was precise, accurate, selective and sensitive for the simultaneous analysis of clobetasol propionate and calcipotriol. The proposed method can be easily applied for the simultaneous determination of clobetasol propionate and calcipotriol in prepared emulgel formulations. The obtained validation results showed that the RP-LC method is suitable for routine quantification of clobetasol propionate and calcipotriol in emulgel formulations with high precision and accuracy.     

Determination of Rosuvastatin in Pharmaceutical Formulations by Capillary Zone Electrophoresis

A capillary zone electrophoretic method with diode array detection was developed and validated for the determination of rosuvastatin calcium in pharmaceutical formulations. Using fused-silica capillary (i.d. 50.0 μm, total length 48.5 cm and effective length 40.0 cm), the influence of the buffer composition, buffer pH and buffer concentration, as well as organic modifier, applied voltage, capillary temperature and injection time were investigated to optimize the method. Optimum results were obtained with 50.0 mM borate buffer at pH 9.5, capillary temperature 30 °C and applied voltage 25 kV. The samples were injected hydrodynamically for 5 s at 50 mbar. Detection wavelength was set at 243 nm. Diflunisal was used as internal standard. The migration times of rosuvastatin calcium and diflunisal were 3.20 ± 0.01 and 4.20 ± 0.02. The total time of analysis was <6 min. The method was validated for rosuvastatin calcium determination in pharmaceutical formulations through following performance parameters: stability, linearity, sensitivity, precision, accuracy, recovery, selectivity, robustness and ruggedness. The linear calibration range was 3.00–200.00 μg mL^?1 and the limits of detection and quantification were 1.00 and 3.00 μg mL^?1 with RSD of 4.38 and 3.09%. The proposed method was applied for the determination of rosuvastatin calcium in its pharmaceutical formulation.     

Stereoselective Determination of Ornidazole Enantiomers in Human Plasma and Urine Samples by Chiral LC: Application to Pharmacokinetic Study

A stereoselective liquid chromatographic method to determine the enantiomers of ornidazole in human plasma and urine has been developed and validated. After addition of the internal standard (naproxen), samples were acidified and extracted with diethyl ether. The separation was performed on a Chiralcel OB-H column, using hexane-ethanol- glacial acetic acid (94:6:0.08, v/v) as the mobile phase. The method was validated for specificity, linearity, sensitivity, precision, accuracy and stability. For each enantiomer of ornidazole, linear calibration curves were obtained over the concentration range of 0.16–20 μg mL^?1 in plasma and 0.32–20 μg mL^?1 in urine. For both enantiomers of ornidazole in plasma and urine, the coefficient of variation for precision were consistently less than 12% and accuracy were within ±14% in terms of relative error. Application of the method to a preliminary pharmacokinetic study showed that this validated method was qualified for the direct determination of ornidazole enantiomers in human plasma and urine.     

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.     

Improved Multianalyte Determination of the Intense Sweeteners Aspartame and Acesulfame‐K with a Solid Sensing Zone Implemented in an FIA Scheme

Abstract

A multianalyte flow‐through sensor is proposed for the simultaneous determination of aspartame (AS) and acesulfame‐K (AK) in tabletop sweeteners. The procedure is based on the transient retention of AK in the ion exchanger Sephadex DEAE A‐25 placed in the flow‐through cell of a monochannel flow injection analysis (FIA) set‐up using pH 2.70 ortophosphoric acid/sodium dihydrogen phosphate buffer 0.06 M as carrier. In these conditions AS is very weakly retained, which makes it possible to measure the intrinsic ultraviolet (UV) absorbance of first AS and then AK after desorption by the carrier itself. The applicable concentration range, the detection limit, and the relative standard deviation were the following: for AS, from 10 to 100 µg mL^?1; 5.65 µg mL^?1; 3.4% (at 50 µg mL^?1); and for AK, between 40 and 100 µg mL^?1; 11.9 µg mL^?1 and 1.61% (at 50 µg mL^?1). The method was applied and validated satisfactorily for the determination of AS and AK blends in tabletop sweeteners. The results were compared against an HPLC reference method.     

Development and Validation of an HPLC–UV Method for the Determination of Insulin in Rat Plasma: Application to Pharmacokinetic Study

A simple, sensitive high performance liquid chromatographic method with UV detection was developed and validated for determination of insulin in rat plasma, using methyl paraben as an internal standard. Insulin was extracted from plasma by a liquid–liquid extraction with a mixture of dichloromethane and n-hexane (1:1, v/v) followed by an acidic back extraction. Chromatographic separation was achieved isocratically with a Phenomenex® C₁₈ analytical column (150 × 4.6 mm ID, 5 μm) at ambient room temperature. The calibration curves were linear within a concentration range of 0.7–8.4 μg mL^?1 (r ² = 0.9994). The inter-day and intra-day accuracy and precision were ≤3.33 and ≤5.55%. The limit of detection (LOD) and limit of quantification (LOQ) were 0.35 and 0.7 μg mL^?1. The average recovery was 87.86% for insulin and 83.52% for methyl paraben. Insulin containing plasma samples were stable at ?20 °C for 7 days. Validated HPLC method was successfully applied to a pharmacokinetic study of insulin in streptozotocin induced diabetic rats.     

Simultaneous Determination of Theobromine,Paraxanthine, Theophylline,and Caffeine in Urine by Reversed-Phase High-Performance Liquid Chromatography with Diode Array UV Detection

A reversed-phase high performance liquid chromatographic method was improved for the simultaneous determination of theobromine, paraxanthine, theophylline, and caffeine in urine. The method includes a liquid-liquid extraction at alkaline pH with ethylacetate. The 7-(2,3-dihidroxypropyl) theophylline was used as an internal standard (ISTD). The separation was achieved on a C₁₈ column using 14:86 methanol:buffer (25 mM KH₂PO₄ adjusted to pH 4 with ortho-phosphoric acid) solution as mobile phase under isocratic conditions at a flow rate 1 mL min^?1. An ultraviolet absorption at 274 nm was monitored. In these conditions, the LOD was 0.03 μg mL^?1 for theobromine, 0.02 μg mL^?1 for paraxanthine, 0.04 μg mL^?1 for theophylline, and 0.08 μg mL^?1 for caffeine. The method has been applied to urine samples.     

LC Determination of a Novel Synthetic Thiazolidinedione (BP-1107) in Rat Plasma and Its Application to a Pharmacokinetic Study

A simple, rapid, sensitive and reliable liquid chromatographic method for the quantification of BP-1107 in rat plasma has been established. Plasma samples were prepared by extraction with tert-butyl methyl ether, and troglitazone was used as an internal standard. The analytical separation was performed on a C₁₈ column using acetonitrile–0.3% phosphoric acid in water (pH 4.00 adjusted with triethylamine) (75:25, v/v) as a mobile phase. A detailed validation of the method was performed as per USFDA guidelines. For BP-1107 at the concentrations of 2.42, 16.11 and 32.22 μg mL^?1 in rat plasma, the extraction recoveries were 114.14 ± 9.75, 95.37 ± 12.06 and 90.00 ± 6.46%, respectively. The mean recovery for internal standard was 91.96 ± 2.51%. The lower limit of quantitation of BP-1107 was 16 ng. The linear quantification range of the method was 0.81–53.70 μg mL^?1 in rat plasma with a correlation coefficient greater than 0.999. The intra-day and inter-day accuracy for BP-1107 at 2.42, 16.11 and 32.22 μg mL^?1 levels in rat plasma fell between 97.10–110.02 and 97.52–108.04%. The intra-day and inter-day precision were in the ranges of 1.91–5.63 and 4.43–6.28%, respectively. The method was successfully applied to a pharmacokinetic study of BP-1107 in rats after an intravenous administration.     

LC Determination and Pharmacokinetic Study of Gemfibrozil in Human Plasma

A simple and sensitive LC method for the quantitative determination of gemfibrozil in human plasma samples is described. Mometasone furoate was used as the internal standard. Plasma samples were pretreated by protein precipitation using methanol. Separation was performed at 40 °C on a YMC^® ODS-A reverse phase column (5 μm particle size, 150 mm × 4.6 mm i.d.) using 0.2% (v/v) triethylamine in water (adjusting to pH 4.0 with phosphoric acid) and acetonitrile (45:55, v/v) as mobile phase which was delivered at 1.5 mL min^?1. Ultraviolet detection was performed at 230 nm. The linear concentration range for gemfibrozil was 0.25–50 μg mL^?1. The detection limit of this method was 0.1 μg mL^?1. Intra- and inter-assay RSD ranged from 0.63 to 2.04% and 1.37 to 4.27%, respectively. The method was sensitive, simple and repeatable enough to be used in pharmacokinetic studies.