ABSTRACT
Piroxicam has two different crystalline forms (known as needle and cubic forms), that they are different in physicochemical properties such as biological solubility. In the current research, using Taguchi experimental design approach the influences of five operating variables on formation of the piroxicam polymorph shapes in recrystallization were studied. The variables include type of solvent, cooling methods, type of mixture paddle, pH, and agitator speed. Statistical analysis of results revealed the significance order of factors affecting the product quality and quantity. At first using the Taguchi experimental method, the influence of process factors on the yield, particle size and dissolution rate of piroxicam powder was statistically investigated. The optimum conditions to achieve the best dissolution rate of piroxicam were determined experimentally. The results were analyzed using Qualitek4 software and it was revealed that the type of solvent and method of cooling respectively are the most important factors that affect the dissolution rate. It was also experimentally achieved that some factors such as type of agitator paddle, pH and agitation rate have no significant effects on dissolution rate.
ABSTRACT
A rapid and sensitive high-performance liquid chromatographic method was developed and validated for determination of oxazepam in serum. Oxazepam was isolated from biological fluid using a simple liquid-liquid extraction with dichloromethane. Nordazepam was used as the internal standard. The chromatographic separation was accomplished using a 125 x 4-mm (inner diameter) stainless-steel (5 microm) Perfectsil Target ODS-3 reversed phase column with a mobile phase consisting of ammonium dihydrogen phosphate buffer (0.05 mol x L(-1), pH 5.8) and methanol (50:50, v/v), running at a flow rate of 1.5 ml x min(-1). The absorbance of the fluent was monitored at 254 nm. The developed method resulted in totally symmetrical peaks. It has been applied to assess the pharmacokinetics of oxazepam. Also the bioequivalence of two different oxazepam preparations following oral administration in healthy volunteers was assessed by this method.
Subject(s)
Anti-Anxiety Agents/blood , Chromatography, High Pressure Liquid/methods , Oxazepam/blood , Administration, Oral , Adult , Anti-Anxiety Agents/pharmacokinetics , Humans , Male , Oxazepam/pharmacokinetics , Reference Standards , Reproducibility of Results , Therapeutic EquivalencyABSTRACT
The present research was designated to evaluate a rapid and sensitive method for determining low concentrations of the highly active drug lorazepam in serum. Isolation of the drug from biological fluid after addition of nordazepam as the internal standard was achieved using a simple liquid-liquid extraction with dichloromethane and the extracted compounds were quantified by high-performance liquid chromatography. Chromatographic separation on a reversed phase column containing a stationary phase with low silanol activity resulted in a perfectly symmetrical peak with a tailing factor of 1.0. The limit of quantitation in serum is 2.5 ng mL(-1) for both lorazepam and internal standard. The procedure is rapid and sensitive enough for determination of lorazepam in serum.
