Determination of paracetamol and orphenadrine citrate in pharmaceutical tablets by modeling of spectrophotometric data using partial least-squares and artificial neural networks.
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The estimation of paracetamol and orphenadrine citrate in a multicomponent pharmaceutical dosage form by spectrophotometric method has been reported. Because of highly interference in the spectra and the presence of non-linearity caused by the analyte concentrations which deviate from Beer and Lambert's law, partial least-squares (PLS) and artificial neural networks (ANN) techniques were used for the calibration. A validation set of spiked samples was employed for testing the accuracy and precision of the methods. Reasonably good recoveries were obtained with PLS for paracetamol and the use of an ANN allowed the estimation of orphenadrine citrate, a minor component which could not be adequately modeled by PLS. Three production batches of a commercial sample were analysed, and there was statistically no significant difference (P<0.05) between the results with the proposed method and those obtain with the official comparative method. (+info)
The use and potential abuse of anticholinergic antiparkinson drugs in Norway: a pharmacoepidemiological study.
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Influence of orphenadrine upon the protective activity of various antiepileptics in the maximal electroshock-induced convulsions in mice.
(12/28)
Orphenadrine is an anticholinergic drug used in the treatment of Parkinson's disease, and is also known to exert nonspecific antagonistic activity at the phencyclidine binding site of the N-methyl-D-aspartate (NMDA) receptor. The aim of this study was to assess the anticonvulsant properties of orphenadrine and to evaluate its effect on the anticonvulsant activity of antiepileptic drugs against maximal electroshock-induced seizures in mice. Orphenadrine given at a dose of 5.65 mg/kg elevated the electrical seizure threshold from 5.7 (5.4-6.1) to 6.8 (6.3-7.3) mA, while a dose of 2.8 mg/kg was ineffective. The ED(50) values of orphenadrine administered 10, 30 and 120 min before maximal electroshock-induced convulsions were 16.8 (11.3-25.1), 17.8 (15.7-20.0) and 25.6 (23.3-28.3) mg/kg, respectively. Orphenadrine at a sub-threshold dose of 2.8 mg/kg significantly enhanced the anticonvulsant activity of valproate by reducing its ED(50) value from 315.8 (270.0-369.4) to 245.9 (207.1-292.0) mg/kg without affecting the free plasma levels of valproate. However, orphenadrine failed to enhance the protective activity of carbamazepine, phenytoin, phenobarbital, lamotrigine, topiramate, or oxcarbazepine against maximal electroshock-induced seizures. (+info)
Validated stability-indicating reversed-phase-HPLC method for simultaneous determination of orphenadrine citrate, caffeine and aspirin.
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New, simple, rapid and precise reversed-phase high-performance liquid chromatographic method was developed for the simultaneous determination of orphenadrine citrate, caffeine and aspirin in presence of aspirin degradation products, orphenadrine citrate and caffeine process related impurities, and excipients. Good resolution and quantization were achieved on reversed-phase column [Phenomenex Luna ODS C(18) (25 cmx4.6 mm, 5 microm particles)]. Gradient elution based on; eluant [A]: 0.1% triethylamine in aqueous potassium dihydrogen phosphate buffer (50 mM; pH 3.0), while as, eluant [B]: acetonitrile, at a flow rate of 1.5 mL min(-1). UV quantitation was set at 215 nm. Linearity was exhibited for orphenadrine citrate, caffeine and aspirin within 0.5-150, 0.5-360 or 0.7-301 microg mL(-1) ranges, respectively. Satisfactory validation results were ascertained in terms of low limits of quantiation (6.33x10(-2)-7.94x10(-2)), mean percentage recovery (98.9-101.4%), precision (<2%) and robustness. The proposed method was proved to be specific, robust and accurate for the determination of cited drugs in pharmaceutical preparations in presence of their degradation products. (+info)
Liver tumor promoting effect of orphenadrine in rats and its possible mechanism of action including CAR activation and oxidative stress.
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Orphenadrine (ORPH), an anticholinergic agent, is a cytochrome P450 (CYP) 2B inducer. CYP2B inducers are known to have liver tumor-promoting effects in rats. In this study, we performed a rat two-stage liver carcinogenesis bioassay to examine the tumor-promoting effect of ORPH and to clarify its possible mechanism of action. Male rats were given a single intraperitoneal injection of N-diethylnitrosamine (DEN) as an initiation treatment. Two weeks after DEN administration, rats were fed a diet containing ORPH (0, 750, or 1,500 ppm) for 6 weeks. One week after the ORPH-administration rats were subjected to two-thirds partial hepatectomy for the acceleration of hepatocellular proliferation. The number and area of glutathione S-transferase placental form-positive foci significantly increased in the DEN-ORPH groups. Real-time RT-PCR revealed increased mRNA expression levels of Cyp2b1/2, Mrp2 and Cyclin D1 in the DEN-ORPH groups and of Gpx2 and Gstm3 in the DEN-High ORPH group. Microsomal reactive oxygen species (ROS) production and oxidative stress markers such as thiobarbituric acid-reactive substances and 8-hydroxydeoxyguanosine were increased in the DEN-High ORPH group. Immunohistochemically, constitutively active/androstane receptor (CAR) were clearly localized in the nuclei of hepatocytes in the DEN-ORPH groups. These results suggest that ORPH causes nuclear translocation of CAR resulting in the induction of the liver tumor-promoting activity. Furthermore, oxidative stress resulting from ROS production is also involved in the liver tumor-promoting activity of ORPH. (+info)
Enhanced liver tumor promotion activity in rats subjected to combined administration of phenobarbital and orphenadrine.
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Phenobarbital (PB) and orphenadrine (ORPH) are cytochrome P450 (CYP) 2B inducers and have liver tumor-promoting effects in rats. In this study, we performed a rat two-stage liver carcinogenesis bioassay to examine the tumor-promoting effect of PB and ORPH co-administration. Twelve male rats per group were given an intraperitoneal injection of N-diethylnitrosamine (DEN) for initiation. Two-week after DEN administration, rats were given PB (60 or 120 ppm in drinking water), ORPH (750 or 1,500 ppm in diet) or 60 ppm PB+750 ppm ORPH for 6-week. One-week after the PB/ORPH treatment, all rats were subjected to two-thirds partial hepatectomy. To evaluate the effect of the combined administration, we used two statistical models: a heteroadditive model and an isoadditive model. In the heteroadditive model, the net values of the number and area of glutathione S-transferase placental form (GST-P) positive foci, Cyp2b1/2, Gstm3 and Gpx2 mRNA levels, microsomal reactive oxygen species (ROS) production and thiobarbituric acid-reactive substances level in the PB+ORPH group were significantly higher than the sum of the net values of those in the Low PB and Low ORPH groups. In the isoadditive model, the average values of the area of GST-P positive foci and PCNA positive hepatocyte ratio and Gstm3 mRNA level in the PB+ORPH group were significantly higher than the average values of those in the High PB and High ORPH groups. These results suggest that PB and ORPH co-administration causes synergistic effects in liver tumor-promoting activity in rats resulting from oxidative stress due to enhanced microsomal ROS production. (+info)
Preclinical evaluation of marketed sodium channel blockers in a rat model of myotonia discloses promising antimyotonic drugs.
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