A simple reversed phase HPLC method have been successfully developed and validated for the quantitative determination of moxifloxacin (MOX) in bulk material, pharmaceutical formulation and serum. Purospher STAR C18 (25 cm × 4.6 mm, 5 μm) and Discovery C18 (25 cm × 4.6 mm, 5 μm) columns were used. The mobile phase, methanol: acetonitrile: water (85:5:10, v/v/v), pH 2.75 adjusted by phosphoric acid was delivered at a flow rate of 1 mL min−1. The eluents was monitored using UV detector at 290 nm. The proposed method is specific, accurate (99.39‐102.67%), precise (intra‐day variation 0.04‐0.86% and inter‐day variation 0.12‐0.94%) and linearity (R2 > 0.999) within the desired range 0.39‐25 μg mL−1 concentration. The detection and quantification limit was 0.002‐0.51 μg mL−1 and 0.01‐0.555 μg mL−1, respectively. The analysis of variance (ANOVA) and student's t‐test were applied to verify the results. The anticipated method is applicable to routine analysis of MOX in pharmaceutical formulations and human serum samples. It is also applied on interaction of MOX with several essential and trace metals as well as interaction with antacids.
This paper describes tryptophan (TRP) estimation in raw human plasma and rat brain by reversed-phase high-performance liquid chromatography (RP-HPLC). Estimation was carried out on a Purospher STAR C18 column using water-acetonitrile (90:10 v/v, at pH 2.7) mixture at a rate of 1.5 mL/min as mobile phase. Eluents were monitored at 273 nm by an ultraviolet detector. The method was linear (R(2) > 0.999), precise (intra-day and inter-day precision <2%) in the range of 0.25-20 µg/mL. The detection and quantification limits were 0.0144 µg/mL and 0.0437 µg/mL, respectively. In human plasma, Day 1 and Day 2 precision were 0.054-2.29% and 1.66-3.7%; whereas precisions in rat brain were 1.23-2.3% and 0.677-4.2%, respectively. The method was applied to study TRP level in human smokers and in arthritic rat brain. An efficient RP-HPLC method was developed for TRP determination that worked for clinical and research purposes.
Leflunomide is a leading drug for the treatment of rheumatoid arthritis. The principle aim of this study was to develop and validate an RP-HPLC method for the determination of leflunomide in bulk and pharmaceutical dosage form using diclofenac sodium as an internal standard. For this purpose, chromatography was accomplished on a Purospher Start, C 18 (5 µm, 12.5 cm×0.46 cm) column at ambient temperature. Methanol∶water (80∶20, V/V) solvent system was selected as mobile phase, the pH of which was adjusted to 3.4 by ortho-phosphoric acid and delivered at a flow rate of 1.2 mL•min -1 . Seperation of leflunomide and diclofenac sodium was carried out on a Purospher Start, C 18 equipped with a UV-visible detector at 248 nm. The suitability of the method for the quantitative determination of the drugs is proven by validation in accordance with the requirements laid down by the International Conference on Harmonization (ICH) guidelines. The method was accurate (99.55%-100.03%), specific, linear (R 2 >0.999) and precise (intra-day precision 0.023%-0.93% and inter-day precision 0.26%-0.944%) in the range of 0.5-20 µg•mL -1 . The minimum limit of detection and quantification in pharmaceutical formulation were 0.05 and 0.15 µg•mL -1 , respectively. Thus the proposed method is simple, accurate, reproducible and suitable for the routine analysis of leflunomide in pharmaceutical formulations and was applied to study in vitro drug-metal interactions.Keywords leflunomide, liquid chromatography, analytical method, in vitro interaction, metal 1934 www.cjc.wiley-vch.de
Abstract:The objective of the study was to evaluate the drug-drug interaction studies of levoceterizine with atenolol. Calibration curve studies of working standard solutions of levocetirizine and atenolol (0.01~0.1 mmol) were scanned. Maxima appeared at 231 nm for levocetirizine and 224 nm for atenolol. The calibration curve obeyed Beer Lambert's Law. Lone availabilities of both the drugs were studied in pH 1, pH 4, pH 7.4 and pH 9 at 37 °C on B.P. (British Pharmacopoeia) dissolution apparatus. To study the drug-drug interaction of levocetirizine (5 mg tablet) and atenolol (100 mg tablet), both the drugs were introduced to the dissolution apparatus in simulated gastric juice (pH 1), pH 4, pH 7.4 and pH 9 at 37 °C at zero time and measured the absorbance maxima of both the drugs at the corresponding wavelength. Graphs were plotted for availability percentage (%) of drug versus time at each set of experiment. The availability percentage (%) of levocetirizine in the buffers of pH simulated to gastric pH 4, pH 7.4 and pH 9 in the presence of atenolol was 436.78%, 376.90%, 436.78% and 436.78%, respectively, but the availability of atenolol was increased up to 214.80%, 212.96%, 214.93% and 231.51% in simulated to gastric pH and in the buffers of pH 4, pH 7.4 and pH 9, respectively. On the basis of these studies, it is concluded that levocetirizine forms a charge-complex with atenolol; therefore, co-administration of these drugs should be avoided.
Leflunomide is an isoxazole immunomodulating drug used to treat rheumatoid arthritis (RA). It is adopted as a metal-containing molecule to proceed with saturated salts of essential and detected metals; it amends the pharmacokinetic and pharmacodynamics activity of leflunomide to provide [M(Lef)4]X2-type complexes. Earlier it has been reported that after forming complexes with metals, leflunomide anti-arthritic activity was significantly altered in an acute arthritic model. In the present study, we evaluated the possible modification in anti-arthritic activities of leflunomide–metal complexes (Mg+2, Ca+2, Fe+2, Zn+2) with and without an anti-depressant drug, i.e., fluoxetine (10 mg/kg) in a chronic AIA model. Rats (n = 5) were administered with 0.1 mL of CFA into the right hind paw while treated groups received leflunomide and its metal complexes orally (3.2 mg/kg) for 24 days. On the final day of experiment, rats were sacrificed; a specific rat immunoassay ELISA kit was used to assess TNF-α in serum samples and read at 450 nm; a tissue sample of a paw was homogenized in a phosphate buffer using DCFH-DA dye for binding to assess ROS. A rat’s brain sample was homogenized and evaluated for tryptophan, serotonin (5-HT), and HIAA by RP-HPLC with EC detector. The overall TNF production was altered in treated rats. In addition, a decreased ROS was observed in all categories, except lef+Mg+2 group. Moreover, depletion in the brain indolamine levels were found in treated groups; an upraised level of these indolamines was observed when fluoxetine was added. It is concluded that metals affect leflunomide activity on complexation and simultaneous administration of fluoxetine cope up with the depression in arthritic-induced rats.
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