Simultaneous high-performance liquid chromatographic analysis for famotidine, ranitidine HCl, cimetidine, and nizatidine in commercial products

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.

HPLC fluorescence method for the determination of nizatidine in human plasma and its application to pharmacokinetic study

A sensitive high-performance liquid chromatographic (HPLC) method was developed for the determination of nizatidine in human plasma. Nizatidine was derivatized by 4-fluoro-7-nitrobenzofurazan (NBD-F). Chromatographic separation was performed on a Inertsil C18 column (150 mm × 4.6 mm, 5 µm) using isocratic elution by a mobile phase consisting of methanol/water (55:45) at a flow rate of 1.2 mL/min. Amlodipine was used as the internal standard (IS). Fluorescence detector was used operated at 461 nm (excitation) and 517 nm (emission), respectively. The calibration curve was linear over the range of 50-2000 ng/mL. This method was successfully applied to a pharmacokinetic study after oral administration of a dose (150 mg) of nizatidine.

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.

Utility of N-bromosuccinimide for the titrimetric and spectrophotometric determination of famotidine in pharmaceutical formulations

Two titrimetric and two spectrophotometric methods are described for the assay of famotidine (FMT) in tablets using N-bromosuccinimide (NBS). The first titrimetric method is direct in which FMT is titrated directly with NBS in HCl medium using methyl orange as indicator (method A). The remaining three methods are indirect in which the unreacted NBS is determined after the complete reaction between FMT and NBS by iodometric back titration (method B) or by reacting with a fixed amount of either indigo carmine (method C) or neutral red (method D). The method A and method B are applicable over the range of 2–9 mg and 1–7 mg, respectively. In spectrophotometric methods, Beer's law is obeyed over the concentration ranges of 0.75–6.0 μg mL⁻¹ (method C) and 0.3–3.0 μg mL⁻¹ (method D). The applicability of the developed methods was demonstrated by the determination of FMT in pure drug as well as in tablets.

Development and validation of an ultra-fast liquid chromatographic method for the quality control of famotidine formulations using a short monolithic stationary phase

An HPLC method for the quality control of famotidine (FMT) containing formulations has been developed and validated. The combination of a short monolithic column (Chromolith® RP-18e 50 × 4.6 mm i.d.) and an elevated flow rate (3.0 mL min−1) enabled the proposal of a high-throughput analytical scheme capable of reliable operation in a demanding industrial environment. Detection was carried out at 265 nm. Thorough validation of the method included linearity (5–150%), limits of detection (0.13%) and quantification (0.41%), selectivity, precision (within- and day-to-day), accuracy and ruggedness. The new method was applied successfully to the analysis of samples (assay, dissolution, dosage & blending uniformity) during the production of four validation batches of FMT-containing tablets.

[Improvement of dissolution test using microdialysis method]

Dissolution testing is a core performance test in pharmaceutical development and quality control. Generally, the HPLC method uses the analysis of dissolution testing. In this study, we attempted to improve the dissolution test by using microdialysis methods. We also investigated the comparison of the conventional HPLC dissolution method (batch-sampling method) and the improved dissolution test (microdialysis method). Histamine H(2)-receptor antagonist cimetidine tablets (200 mg), which are used clinically and of which there are also some generic examples, were selected for this comparison, and the dissolution behavior of the tablets by the two methods were found to be similar. On the other hand, standard deviation in the microdialysis method was lower than that of the batch-sampling method. In addition, the microdialysis method can omit many steps such as the filtration, collection and replenishment of sample solutions, and is also able to accomplish continuous sampling of sample solutions. These findings provide significant information that can be used in the pharmaceutical development and quality control of original and generic products.

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%).

Stability indicating method for famotidine in pharmaceuticals using porous graphitic carbon column

A simple, sensitive and rapid HPLC method was developed and validated for the simultaneous determination of famotidine (FMT) and related impurities in pharmaceuticals. Chromatographic separation was accomplished within 10 min on a porous graphitic carbon (PGC) column using 50:50 v/v ACN-water containing 0.5% pentane sulphonic acid (PSA) as the mobile phase. Separation was achieved with a flow rate of 1 mL/min and a detection wavelength of 265 nm. The calibration curves were linear over a concentration range of 1.5-100 microg/mL. The intra- and interday RSDs (n = 5) for the retention times and peak area were all less than 2%. The method was sensitive with an LOD (S/N = 3) of 0.1 microg/mL for FMT, imp. C and 0.05 microg/mL for imp. 2, A and D. All recoveries were greater than 98%. The method was demonstrated to be precise, accurate and specific with no interference from the tablet ingredients and separation of the drug peak from the peaks of the degradation products (oxidative degradation and acid and base degradation). The results indicated that the proposed method could be used for the determination of FMT in commercial dosage forms and as a stability-indicating assay.

A sensitive spectrophotometric method for the determination of H2-receptor antagonists by means of N-bromosuccinimide and p-aminophenol

A simple, accurate and sensitive spectrophotometric method for determination of H2-receptor antagonists: cimetidine (CIM), famotidine (FAM), nizatidine (NIZ), and ranitidine hydrochloride (RAN) has been fully developed and validated. The method was based on the reaction of these drugs with NBS and subsequent measurement of the excess N-bromosuccinimide by its reaction with p-aminophenol to give a violet colored product (lambda max at 552 nm). Decrease in the absorption intensity (Delta A) of the colored product, due to the presence of the drug, was correlated with its concentration in the sample solution. Different variables affecting the reaction were carefully studied and optimized. Under optimal conditions, linear relationships with good correlation coefficients (0.9988-0.9998) were found between Delta A values and the corresponding concentrations of the drugs in a concentration range of 8-30, 6-22, 6-25, and 4-20 microg mL(-1) for CIM, FAM, NIZ, and RAN, respectively. Limits of detection were 1.22, 1.01, 1.08, and 0.74 microg mL(-1) for CIM, FAM, NIZ, and RAN, respectively. The method was validated in terms of accuracy, precision, ruggedness, and robustness; the results were satisfactory. The proposed method was successfully applied to the analysis of the above mentioned drugs in bulk substance and in pharmaceutical dosage forms; percent recoveries ranged from 98.5 +/- 0.9 to 102.4 +/- 0.8% without interference from the common excipients. The results obtained by the proposed method were comparable with those obtained by the official methods.

Simple and universal HPLC-UV method to determine cimetidine, ranitidine, famotidine and nizatidine in urine: application to the analysis of ranitidine and its metabolites in human volunteers

A validated, simple and universal HPLC-UV method for the determination of cimetidine, famotidine, nizatidine and ranitidine in human urine is presented. This is the first single HPLC method reported for the analysis of all four H(2) antagonists in human biological samples. This method was also utilized for the analysis of ranitidine and its metabolites in human urine. All calibration curves showed good linear regression (r(2)>0.9960) within test ranges. The method showed good precision and accuracy with overall intra- and inter-day variations of 0.2-13.6% and 0.2-12.1%, respectively. Separation of ranitidine and its metabolites using this assay provided significantly improved resolution, precision and accuracy compared to previously reported methods. The assay was successfully applied to a human volunteer study using ranitidine as the model compound.

Optimization and validation of a dissolution test for famotidine tablets using flow injection analysis

A dissolution test for famotidine tablets was optimized and validated using flow injection analysis (FIA). The effect of dissolution parameters such as pH, medium and stirring speed was studied, while the ruggedness of the procedure was validated. All measurements were performed using a simple direct spectrophotometric flow injection assay (lambdamax=265 nm) that has also been optimized and fully validated in terms of linearity, limit of detection, precision, selectivity and accuracy. Linearity was obeyed in the range 50-150% of famotidine (20-60 mg L-1), while the detection limit (0.1 mg L-1) and repeatability (sr<1.0%, n=12) were satisfactory. The sampling rate was 30 h-1. The dissolution results during quality and stability control of two batches of famotidine tablets obtained by the flow injection method were in good agreement with high-performance liquid chromatography (HPLC).

Validation of a New High-Performance Liquid Chromatography Assay for Nizatidine

An expedient high-performance liquid chromatography (HPLC) assay for nizatidine measurement in human plasma was developed and validated. After deproteinization of 200 microL of plasma by filtration, nizatidine and 4-amino-antipyrine (internal standard) were separated (capacity ratio 3.0 and 6.63, respectively) on Nova-Pak C18 cartridge at room temperature (RT), and detected spectrophotometrically at 320 nm. The mobile phase, 0.02 mol/L disodium hydrogen phosphate, acetonitrile, methanol, and triethylamine (80:10:10:0.05 vol/vol), was delivered at 1.5 mL/min. Calibration curves were linear (r2 > or = 0.999) in the range 0.02 to 5 microg/mL, detection and quantification limits were 0.01 and 0.02 microg/mL, respectively, intra-run and inter-run coefficients of variation were < or = 3.5% and < or = 4.2%, respectively, and recovery was >90%. Nizatidine was stable for at least 4 hours at RT, 12 weeks at -20 degrees C, and 3 freeze-thaw cycles in plasma; 16 hours at RT and 48 hours at -20 degrees C in deproteinized plasma; and 6 hours at RT and 3 weeks at -20 degrees C in water.

Ion-Selective Electrodes for Potentiometric Determination of Ranitidine Hydrochloride, Applying Batch and Flow Injection Analysis Techniques

New ranitidine hydrochloride (RaCl)-selective electrodes of the conventional polymer membrane type are described. They are based on incorporation of ranitidine-tetraphenylborate (Ra-TPB) ion-pair or ranitidine-phosphotungstate (RaPT) ion-associate in a poly(vinyl chloride) (PVC) membrane plasticized with dioctylphthalate (DOP) or dibutylphthalate (DBP). The electrodes are fully characterized in terms of the membrane composition, solution temperature, and pH. The sensors showed fast and stable responses. Nernstian response was found over the concentration range of 2.0 x 10(-5) M to 1.0 x 10(-2) M and 1.0 x 10(-5) M to 1.0 x 10(-2) M in the case of Ra-TPB electrode and over the range of 1.03 x 10(-5) M to 1.00 x 10(-2) M and 1.0 x 10(-5) M to 1.0 x 10(-2) M in the case of Ra-PT electrode for batch and FIA systems, respectively. The electrodes exhibit good selectivity for RaCl with respect to a large number of common ions, sugars, amino acids, and components other than ranitidine hydrochloride of the investigated mixed drugs. The electrodes have been applied to the potentiometric determination of RaCl in pure solutions and in pharmaceutical preparations under batch and flow injection conditions with a lower detection limit of 1.26 x 10(-5) M and 5.62 x 10(-6) M at 25 +/- 1 degrees C. An average recovery of 100.91% and 100.42% with a relative standard deviation of 0.72% and 0.53% has been achieved.

Spectrophotometric investigation of famotidine-Pd(II) complex and its analytical application in drug analysis

By using different spectrophotometric methods, it was found that famotidine and palladium(II) ions form a complex, Pd(II): famotidine = 1:1, which has an absorptionmaximum at 345 nm. The formation of the complex between famotidine and palladium(II) chloride in Britton?Robinson buffer solution in the pH range 2.23?8.50 was studied. The conditional stability constant of the complex at the optimum pH 2.62 and ionic strength 0.5M was found to be log K?= 3.742 ??0.025. The Beer?s law was verified over the famotidine concentration range from 5x10-5?6x10-4 M. The proposed method was found to be suitable for accurate and sensitive analysis of famotidine both as the substance (RSD = 1.02?1.80 %) and its dosage forms (RSD = 1.75?1.83 %).

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.

Utility of oxidation-reduction reaction for the determination of ranitidine hydrochloride in pure form, in dosage forms and in the presence of its oxidative degradates

Three simple, accurate and sensitive colorimetric methods (A, B and C) for the determination of ranitidine HCl (RHCl) in bulk sample, in dosage forms and in the presence of its oxidative degradates are described. The first method A is based on the oxidation of the drug by N-bromosuccinimide (NBS) and determination of the unreacted NBS by measurement of the decrease in absorbance of amaranth dye (AM) at a suitable lambda(max)=520 nm. The methods B and C involve the addition of excess Ce(4+) and determination of the unreacted oxidant by decrease the red color of chromotrope 2R (C2R) at a suitable lambda(max)=528 nm for method B or decrease the orange pink color of rhodamine 6G (Rh6G) at a suitable lambda(max)=526 nm for method C. Regression analysis of Beer-Lambert plots showed good correlation in the concentration ranges 0.2-3.6, 0.1-2.8 and 0.1-2.6 microg ml(-1) for methods A, B and C, respectively. The apparent molar absorptivity. Sandell sensitivity, detection and quantitation limits were calculated. For more accurate results, Ringbom optimum concentration ranges were 0.3-3.4, 0.2-2.6 and 0.2-2.4 microg ml(-1) for methods A, B and C, respectively. Analyzing pure and dosage forms containing RHCl tested the validity of the proposed methods. The relative standard deviations were </=1.38 with recoveries 98.9-101.0%.

High-performance liquid chromatographic determination of famotidine in human plasma using solid-phase column extraction

A rapid, specific and sensitive high-performance liquid chromatographic method for the determination of famotidine in human plasma has been developed. Famotidine and the internal standard were chromatographically separated from plasma components using a Lichrocart Lichrospher 60 RP select B cartridge for solid-phase separation with a mobile phase composed of 0.1 % (v/v) triethylamine in water (pH 3) and acetonitrile (92:8, v/v). UV detection was set at 270 nm. The calibration curve was linear in the concentration range of 10.0 ? 350.0 ng mL-1. The method was implemented to monitor the famotidine levels in patient samples.

Kinetic spectrophotometric determination of nizatidine and ranitidine in pharmaceutical preparations

A new simple and sensitive kinetic spectrophotometric method is described for analysis of nizatidine (I) and ranitidine (II). The method involves the reaction of the drugs with alkaline potassium permanganate, whereby a green color peaking at 610 nm is produced. The reaction is monitored spectrophotometrically by measuring the rate of change of absorbance of the resulting manganate species at 610 nm. Calibration graphs are linear over the concentration range 0.8-4.0 microg/ml and the precision (% RSD 1.80, 1.53 for I and II, respectively) is quite acceptable. The method is satisfactorily applied for direct analysis of pharmaceutical preparations containing I and II. A proposal of the reaction pathway is postulated.

Simultaneous determination of cimetidine, famotidine, nizatidine, and ranitidine in tablets by capillary zone electrophoresis

A simple capillary zone electrophoresis (CZE) method is described for the simultaneous determination of cimetidine (CIM), famotidine (FAM), nizatidine (NIZ), and ranitidine (RAN). The analysis of these drugs was performed in a 100 mM phosphate buffer, pH 3.5. Several parameters were studied, including wavelength for detection, concentration and pH of phosphate buffer, and separation voltage. The quantitative ranges were 100-1,000 microM for each analyte. The intra- and interday relative standard deviations (n = 5) were all less than 4%. The detection limits were found to be about 10 microM for CIM, 20 microM for RAN, 20 microM for NIZ, and 10 microM for FAM (S/N = 3, injection 1 s) at 214 nm. All recoveries were greater than 92%. Applications of the method to the assay of these drugs in tablets proved to be feasible.

Validation of a liquid chromatographic method for the determination of ranitidine hydrochloride residues on surfaces in the manufacture of pharmaceuticals

A liquid chromatographic method for determination of the residues of ranitidine hydrochloride on various surfaces employed in drug manufacture is described. Cotton swabs, moistened with a methanol-water (1:1, v/v) mixture were used to remove any residues of drugs from glass, vinyl, and stainless steel surfaces, and gave recoveries of 85%, 78% and 90%, respectively. Residues were determined by high-performance liquid chromatography on a C18 column at 25 degrees C with methanol-ammonium acetate (40:60 v/v) pH 6.7 as the mobile phase and detection at 320 nm. The method was validated over a concentration range of 20-10 000 ng/ml and had a detection limit of 2 ng/ml.