High-performance liquid chromatographic analysis of ranitidine in plasma and urine

Preconcentration and determination of ranitidine hydrochloride in real samples by using modified magnetic iron oxide nanoparticles

This method shows a novel, fast, and simple magnetic solid-phase extraction (SPE) and spectrophotometric procedure for preconcentration and determination of ranitidine hydrochloride in human plasma and aquatic samples by using Fe3O4 nanoparticles (NPs) modified by sodium dodecyl sulfate (SDS) as an extractor. The unique properties of Fe3O4 NPs including high surface area and strong magnetism were utilized effectively in the magnetic SPE process. The determination method is based on the SDS-coated Fe3O4 NPs with extracted ranitidine-HCl, which was subsequently monitored spectrophotometrically at λmax = 320 nm. Effects of different parameters influencing the extraction efficiency of ranitidine-HCl including the pH value, amount of SDS, and Fe3O4 NPs, extraction time, desorption solvent, desorption time, and sample volume were optimized. Under optimized conditions, the method was successfully applied to the extraction of ranitidine-HCl from human plasma and aquatic samples. The extraction recovery in human plasma and different matrixes of waters were investigated and values of 89.0%–103.4% were obtained. The calibration graph for the determination of ranitidine-HCl was linear in the range of 0.025–1.50 μg mL−1 with R2 = 0.9946. The limit of detection of the proposed method was 7.5 × 10−3 μg mL−1. The repeatability and reproducibility (relative standard deviation) of the mentioned method were 0.83% and 1.22%, respectively. The experimental results showed that the proposed method was feasible for the analysis of ranitidine-HCl in environmental and biological samples.

An Overview of Analytical Determination of Diltiazem, Cimetidine, Ranitidine, and Famotidine by UV Spectrophotometry and HPLC Technique

This review article recapitulates the analytical methods for the quantitative determinations of diltiazem and three H2receptor antagonists (cimetidine, ranitidine, and famotidine) by one of the spectroscopic technique (UV spectrophotometery) and separation technique such as high-performance liquid chromatography (HPLC). The clinical and pharmaceutical analysis of these drugs requires effective analytical procedures for quality control, pharmaceutical dosage formulations, and biological fluids. An extensive survey of the literature published in various analytical and pharmaceutical chemistry-related journals has been compiled in its review. A synopsis of reported spectrophotometric and high-performance liquid chromatographic methods for individual drug is integrated. This appraisal illustrates that majority of the HPLC methods reviewed are based on the quantitative analysis of drugs in biological fluids, and they are appropriate for therapeutic drug monitoring purpose.

An environmentally friendly reflectometric method for ranitidine determination in pharmaceuticals and human urine

This paper describes an environmentally friendly method for quantitative determination of ranitidine using diffuse reflectance spectroscopy. This method is based on the reflectance measurements of the colored product produced from the spot test reaction between ranitidine and p-dimethylaminocinnamaldehyde (p-DAC), in acid medium, using filter paper as solid support. Experimental design methodologies were used to optimize the optimal conditions. All reflectance measurements were carried out at 590 nm and the linear range was from 1.42x10(-3) to 3.42x10(-2) mol L(-1), with a correlation coefficient of 0.997. The limit of detection was estimated to be 1.09x10(-3) mol L(-1) (R.S.D.=1.9%). The proposed method was successfully applied to the determination of ranitidine in commercial brands of pharmaceuticals and no interferences were observed from the common excipients in formulations. The results obtained by the proposed method were favorably compared with those obtained by an official procedure at 95% confidence level. Additionally, the method was also applied to the determination of ranitidine in human urine showing excellent recoveries (99.6-100.3%).

Simultaneous determination of amoxicillin and ranitidine in rat plasma by high-performance liquid chromatography

A high-performance liquid chromatography method using ultraviolet detection at 230 nm for the simultaneous determination of amoxicillin and ranitidine in rat plasma has been validated. Plasma samples after pretreatment with acetonitrile to effect deproteinization were dried under N2 and reconstituted with water. The standard calibration curves for amoxicillin and ranitidine were linear (r2=0.9999) over the concentration range of 0.2-20 microg ml-1 and 0.03-6 microg ml-1 in rat plasma, respectively. The intra- and inter-day assay variability range for amoxicillin was 2.4-8.5% and 3.2-11.7%, and for ranitidine was 1.7-9.0% and 4.5-10.1%, respectively. This method has been successfully applied to a pharmacokinetic study after oral coadministration of amoxicillin and ranitidine to rats.

Development of an HPLC method for the determination of ranitidine and cimetidine in human plasma following SPE

A selective, sensitive and accurate high-performance liquid chromatographic method has been developed, validated and applied for the determination of ranitidine and cimetidine in plasma samples. The effects of mobile phase composition, buffer concentration, mobile phase pH and concentration of organic modifiers on retention of investigated drugs were investigated. Sample preparation was carried out by adding an internal standard, famotidine, and the clean-up procedure was accomplished using solid-phase extraction (SPE). This method uses ultraviolet detection, the separation used a Lichrocart Lichrospher 60 RP-select B column and the mobile phase consisted of 0.2% triethylamine (TEA), 0.04 mol l(-1) KH2PO4 at pH 6.8 and 14% acetonitrile. The recovery, selectivity, linearity, precision and accuracy of the method were evaluated from spiked human plasma. The method has been implemented to monitor ranitidine levels in clinical samples.

Rapid determination of ranitidine in human plasma by high-performance liquid chromatography without solvent extraction

A simple high-performance liquid chromatographic procedure was developed for the determination of ranitidine in human plasma. The method entailed direct injection of the plasma samples after deproteination using perchloric acid. The chromatographic separation was accomplished with an isocratic elution using mobile phase consisting of 21 mM disodium hydrogen phosphate-triethylamine-acetonitrile (1000:60:150, v/v), pH 3.5. Analyses were run at a flow-rate of 1.3 ml/min using a microbondapak C18 column and ultraviolet detection at a wavelength of 320 nm. The method was specific and sensitive, with a quantification limit of approximately 20 ng/ml and a detection limit of 5 ng/ml at a signal-to-noise ratio of 3:1. The mean absolute recovery was about 96%, while the within- and between-day coefficient of variation and percent error values of the assay method were all less than 8%. The linearity was assessed in the range of 20-1000 ng/ml plasma, with a correlation coefficient of greater than 0.999. This method has been used to analyze several hundred human plasma samples for bioavailability studies.

Automated in-tube solid-phase microextraction-liquid chromatography-electrospray ionization mass spectrometry for the determination of ranitidine

The technique of automated in-tube solid-phase microextraction (SPME) coupled with liquid chromatography-electrospray ionization mass spectrometry (LC-ESI-MS) was evaluated for the determination of ranitidine. In-tube SPME is an extraction technique for organic compounds in aqueous samples, in which analytes are extracted from the sample directly into an open tubular capillary column by repeated aspirate/dispense steps. In order to optimize the extraction of ranitidine, several in-tube SPME parameters such as capillary column stationary phase, extraction pH and number and volume of aspirate/dispense steps were investigated. The optimum extraction conditions for ranitidine from aqueous samples were 10 aspirate/dispense steps of 30 microliters of sample in 25 mM Tris-HCl (pH 8.5) with an Omegawax 250 capillary column (60 cm x 0.25 mm I.D., 0.25 micron film thickness). The ranitidine extracted on the capillary column was easily desorbed with methanol, and then transported to the Supelcosil LC-CN column with the mobile phase methanol-2-propanol-5 M ammonium acetate (50:50:1). The ranitidine eluted from the column was determined by ESI-MS in selected ion monitoring mode. In-tube SPME followed by LC-ESI-MS was performed automatically using the HP 1100 autosampler. Each analysis required 16 min, and carryover of ranitidine in this system was below 1%. The calibration curve of ranitidine in the range of 5-1000 ng/ml was linear with a correlation coefficient of 0.9997 (n = 24), and a detection limit at a signal-to-noise ratio of three was ca. 1.4 ng/ml. The within-day and between-day variations in ranitidine analysis were 2.5 and 6.2% (n = 5), respectively. This method was also applied for the analyses of tablet and urine samples.

Evaluation of sex differences in the pharmacokinetics of ranitidine in humans

A bioequivalence study of two oral formulations of 300 mg ranitidine was carried out in 16 healthy volunteers (8 men and 8 women), and the pharmacokinetics in both sexes were compared. There was bioequivalence of both formulations. The terminal half-life of ranitidine was 7% shorter and the oral apparent clearance 10.5% higher in women (1.44 L/h/kg) than in men (1.29 L/h/kg), although this difference did not reach statistical significance. No differences were observed in maximum concentration (Cmax) or the time of its occurrence (tmax). Sex, age, and weight did not correlate significantly with oral clearance. These results suggest that there are no sex differences in the pharmacokinetics of ranitidine, or that any differences would not be of clinical relevance. It also should be emphasized that bioequivalence trials also can be used to study other pharmacokinetic or pharmacodynamic characteristics of drugs without damaging the main endpoint of the study.

Bioanalysis of anti-ulcer agents

In reviewing the analytical methods for the analysis of anti-ulcer drugs we observed an increase in the utilization of solid-phase extraction techniques, though the traditional liquid-liquid methods are still predominant. Liquid chromatographic techniques are employed more than gas chromatographic methods which reflects the general trend in chromatographic analysis for analytes in the nanogram range. We foresee a continued increase in the use of solid-phase extraction methodology (automated or otherwise) due to the potential for dramatic decreases in extraction times, cost and significant enhancement of extraction efficiency. Because the therapeutic concentrations of these drugs tend to be in the low nanogram range in plasma and the current trend in drug development is toward more potent agents, we anticipate the application of more sensitive liquid chromatographic detection techniques such as electrochemical and chemiluminescence detection to overcome the limitations of currently used technology.

The validation criteria for analytical methods used in pharmacy practice research

An integral part of analytical method development is validation, i.e. once the method has been devised it is necessary to evaluate it under the conditions expected for real samples before being used for a specific purpose. Although the validation stage is crucial in method development, the importance of this step is often overlooked. This paper attempts to clarify the nomenclature of method validation and describes the validation procedure for analytical methods used for the determination of drugs in biological fluids and formulations.