Search results for "Dosage"
showing 10 items of 516 documents
Intensity-modulated extended-field chemoradiation plus simultaneous integrated boost in the pre-operative treatment of locally advanced cervical canc…
2015
Objective: To investigate the feasibility and determine the recommended pre-operative intensity-modulated radiotherapy (IMRT) dose of extended-field chemoradiation along with simultaneous integrated boost (SIB) dose escalation. Methods: A radiation dose of 40Gy over 4 weeks, 2Gy/fraction, was delivered to the tumour and the lymphatic drainage (planning target volume, PTV3), which encompassed a volume larger than standard (common iliac lymphatic area up to its apex, in front of the L3 vertebra), concurrently with chemotherapy (cisplatin and 5-fluorouracil). Radiation dose was escalated to the pelvis (PTV2) and to the macroscopic disease (PTV1) with the SIB-IMRT strategy. Three dose levels we…
Performance of micellar mobile phases in reversed-phase chromatography for the analysis of pharmaceuticals containing beta-blockers and other antihyp…
1996
A rapid and simple reversed-phase micellar liquid chromatographic procedure for the simultaneous determination of the beta-blockers atenolol, metoprolol and oxprenolol, the diuretics amiloride, bendroflumethiazide, chlorthalidone and hydrochlorothiazide and the vasodilator hydralazine in pharmaceuticals, is proposed. An interpretive optimization procedure, which uses the chromatographic data for only five mobile phases, was applied to select a suitable micellar mobile phase. A comparative study was also made of the performance of micellar and aqueous-organic mobile phases in the analysis of pharmaceuticals that combine beta-blockers and diuretics. The determination of all the drugs could be…
Antibiotic in vivo/in vitro release, histocompatibility and biodegradation of gentamicin implants based on lactic acid polymers and copolymers
1995
Abstract Biodegradable implants containing 10 mg of gentamicin each were prepared by compressing the polymer-drug mixture. The liberation of gentamicin from the implants and the biodegradation of the implants were investigated by following in vitro and in vivo experiments. Implants based on pure poly( l -lactic acid) (L-PLA) released the incorporated antibiotic throughout 30 days with a decreasing delivery rate. During the first 24 h L-PLA implants released a total amount of 3600 μg gentamicin. Within 14 days the release rate had decreased to about 12 μg/day. The release profile of implants based on dl -lactic acid-glycolic acid copolymer (RG 502) was completely different. About 1900 μg wer…
Photochemical Derivatization and Fluorimetric Determination of Promethazine in a FIA Assembly
1992
Abstract The flow injection fluorimetric determination of promethazine is carried out by on-line photoderivatization. The PTFE tubing is helically coiled around the lamp. An analytical procedure is proposed by using aqueous solution as carrier stream: the calibration graph is linear over the range 0.05 - 20 ppm. The influence of foreign compounds is studied and the method is applied to promethazine determination in pharmaceutical formulations.
HYDRO-ORGANIC AND MICELLAR-ORGANIC REVERSED-PHASE LIQUID CHROMATOGRAPHIC PROCEDURES FOR THE EVALUATION OF SULPHONAMIDES IN PHARMACEUTICALS
2001
Two reversed-phase liquid chromatographic procedures were developed for the analysis of ten pharmaceutical formulations used in medicine and veterinary, which contained one of the following sulphonamides: sulphacetamide, sulphadiazine, sulphaguanidine, sulphamethazine, sulphamethizole, sulphamethoxazole, or sulphathiazole. In both chromatographic modes, the same C18 column was utilized and the mobile phase contained a low amount of acetonitrile and citric buffer at pH 3.0. In one of the procedures, the surfactant sodium dodecyl sul phate was added to the mobile phase. The presence of micelles allowed a decrease in the amount of organic solvent from 11% to 6%, and facilitated sample dissolut…
Determination of Caffeine in Analgesic Formulations Using the Apparent Content Curves Method
1994
Abstract The determination of caffeine by UV spectroscopy in pharmaceutical samples, containing different compounds which provide spectral interferences as aspirin, paracetamol, chlorfeniramine or propylphenazone, is carried out. The proposed procedure is based on the apparent content curves method in order to resolve binary, ternary and multicomponent mixtures. Results obtained are, in all cases, in agreement with contents found by a HPLC procedure used as reference method.
Indirect determination of paracetamol in pharmaceutical formulations by inhibition of the system luminol–H2O2–Fe(CN)63− chemiluminescence
1999
After a large drug scanning, the system Luminol-H2O2-Fe(CN)6(3-) is proposed for first time for the indirect determination of paracetamol. The method is based on the oxidation of paracetamol by hexacyanoferrate (III) and the subsequent inhibitory effect on the reaction between luminol and hydrogen peroxide. The procedure resulted in a linear calibration graph over the range 2.5-12.5 microg ml(-1) of paracetamol with a sample throughput of 87 samples h(-1). The influence of foreign compounds was studied and, the method was applied to determination of the drug in three different pharmaceutical formulations.
Continuous flow-injection-atomic absorption spectrometric method for the determination of Ondansetron
1995
Abstract A flow-injection procedure for the indirect determination of the new drug Ondansetron is proposed. The method is based on the reaction of the drug in an oxidative solid-phase reactor included in the flow assembly. The reactor was made by lead dioxide physically entrapped by polymerization; the released lead(II) was monitored by atomic absorption spectrometry at 217.0 nm. The procedure gave a linear calibration graph up to 20 μg ml−1 of Ondansetron with a sample throughput of 338 samples h−1.
Liquid chromatographic procedure for the evaluation of β-blockers in pharmaceuticals using hybrid micellar mobile phases
1997
Abstract A reversed-phase chromatographic procedure with a micellar eluent is proposed for the determination of several β-blockers (acebutolol, atenolol, carteolol, celiprolol, labetalol, metoprolol, nadolol, oxprenolol, propranolol, and timolol) in pharmaceutical formulations (tablets, capsules, and ophthalamic solutions). A study is shown on the chromatographic behaviour of these drugs with mobile phases containing sodium dodecyl sulphate (0.075–0.15 M ) and propanol (0–15%, v/v), at different pH values (3–7). The excellent correlation between log of the octanol-water partition coefficient and log of capacity factor, for the ten drugs in mobile phases of SDS and propanol, suggested that t…
A new derivatization procedure for the determination of cephalexin with 1,2-naphthoquinone 4-sulphonate in pharmaceutical and urine samples using sol…
1998
Abstract The present report shows how to derivatize cephalexin with 1,2-naphthoquinone-4-sulphonate (NQS) into solid-phase extraction cartridges (C18) using UV–visible detection. Optimum conditions for this new procedure are: hydrogen carbonate/carbonate buffer pH=10.5, 5 min reaction time at 25°C and NQS concentration of 7.1×10−3 mol l−1. The accuracy and the precision of the method were tested. The procedure was used to measure cephalexin in pharmaceutical and urine samples. The results obtained were contrasted with those reported by UV-spectrophotometric and HPLC methods for pharmaceutical samples and with HPLC method for urine samples. The H-point standard additions method was used to m…