Simultaneous interaction, degradation, and kinetic study of sparfloxacin with H2 receptor antagonist.

Sparfloxacin is a quinolone carboxylic acid derivative that shows activity as an antimicrobial agent, against a wide range of Gram-negative and Gram-positive organisms. It is clinically useful for the treatment of urinary tract infections, respiratory tract infections and gynecological infections. In this study in vitro drug-drug interaction of sparfloxacin has been carried out with famotidine and ranitidine. For these studies a two-component spectrophotometric process has been developed for sparfloxacin assay in the presence of famotidine or ranitidine. The reproducibility of the method is within ±5%. The technique has been applied to the development of sparfloxacin in methanol. The interaction studies of sparfloxacin with ranitidine and famotidine were carried out in methanol and methanol: Water mixtures (30:70, v/v; 50:50, v/v) and the kinetics of sparfloxacin degradation were evaluated in the presence and absence of famotidine and ranitidine. The decrease in the rate of degradation of sparfloxacin in the presence of famotidine or ranitidine, compared to that of sparfloxacin alone, indicated the possibility of interaction between the sparfloxacin and famotidine or ranitidine. The Thin layer chromatography (TLC) of the degraded solution showed the presence of a degradation product of sparfloxacin. The studies show that complexation with famotidine or ranitidine may affect the bioavailability of sparfloxacin.

An eco-friendly multi-analyte high-performance thin layer chromatographic densitometric determination of amoxicillin, metronidazole, and famotidine in their ternary mixtures and simulated gastric juice: A promising protocol for eradicating Helicobacter pylori.

Gastrointestinal tract disorders constitute a heavy burden to healthcare providers. To eradicate Helicobacter pylori infection, different triple therapy protocols have been proposed. Among which are combinations of proton pump inhibitors (e.g., omeprazole), histamine-2 receptor antagonists (e.g., famotidine), along with antibiotics (e.g., amoxicillin). In this work, a sensitive and accurate high-performance thin-layer chromatographic method was developed for the simultaneous determination of amoxicillin, metronidazole, and famotidine in bulk powder and laboratory-prepared combined-tablet mixtures. Complete separation of the cited compounds was achieved using pre-coated silica gel plates with a mixture of methanol:chloroform:toluene:water:glacial acetic acid (5:2:1.5:0.5:0.1 v/v/v/v/v) as the mobile phase. The method was fully validated as per the international conference of harmonization guidelines. Good linearity, a correlation coefficient of 0.9991, was obtained in the concentration ranges 0.1-1.6 µg/band (amoxicillin), 0.1-0.9 µg/band (metronidazole), and 0.1-0.9 µg/band (famotidine). Since the method allowed the determination of the three compounds in combined tablets with a high degree of selectivity, accuracy, precision, with cost-effectiveness, it could be used for regular quality control. Moreover, the applicability of the proposed method was extended to the determination of the ternary mixture in simulated gastric juice. Method greenness was assessed using different green metrics.

[Stability of Six Drugs in Total Parenteral Nutrition Solution].

Elneopa NF No. 1 and No. 2 infusions are total parenteral nutrition solutions packaged in four-chambered infusion bags. They have been used as home parenteral nutrition, with various drugs injected into the infusion bags, for treating patient symptoms. In this study, we investigated the stability of six drugs, including famotidine, scopolamine butylbromide, furosemide, bromhexine hydrochloride, betamethasone sodium phosphate, and metoclopramide hydrochloride in the infusion bags under dark conditions at 4℃ for 7 days. Additionally, we developed a high-performance liquid chromatography method to determine drug concentrations in the infusions. The concentrations of injected famotidine, scopolamine butylbromide, and betamethasone sodium phosphate remained unchanged when the four chambers of Elneopa NF No. 1 and No. 2 were opened and the infusions were mixed. Their respective concentrations in the upper and lower chambers also remained unchanged. The concentration of furosemide in the upper chamber of the No. 1 infusion bag decreased after 5 days, although no change was observed in the other chambers and the mixed infusions with the four chambers opened. The concentration of bromhexine hydrochloride slightly decreased in the upper chambers (approximately 3%) after the co-infusion but decreased significantly in the other chambers and the mixed infusions with the four chambers opened. The concentration of metoclopramide hydrochloride significantly decreased in the upper chambers after the co-infusion; however, no change in concentration was observed in the other chambers and the mixed infusion with the four chambers opened. The results of this study provide useful information on home-based parenteral nutrition.

Pentabromobenzyl-RP versus triazole-HILIC columns for separation of the polar basic analytes famotidine and famotidone: LC method development combined with in silico tools to follow the potential consequences of famotidine gastric instability.

The competence of hydrophilic interaction (HILIC) and reversed phase liquid chromatography (RPLC) modes, employing two new stationary phases: triazole- and pentabromobenzyl-bonded silica (PBr), respectively, was inspected for separation of two polar basic analytes: famotidine (FAM) and its acidic degradant famotidone (FON). Comparison of the chromatographic efficiency, greenness, and economy aspects showed that the RPLC is superior to the HILIC. Hence, the RPLC method was adopted and validated adhering to the FDA guidelines showing excellent linearity for FAM (1.0-20.0 µg/mL) with a detection limit of 0.14 µg/mL. The method was applied to study the behavior of FAM in simulated gastric juice (SGJ), where it exhibited rapid degradation yielding FON. This degradation pathway is a probable major reason for the poor bioavailability of FAM. The kinetic study of the gastric degradation of FAM in SGJ demonstrated pseudo-first order reaction with a rate constant of 8.1 × 10-3 min-1. Moreover, FAM degradation has been proven to be pH-dependent and catalyzed by the gastric juice components. Hence, in situ buffered dosage form is recommended to overcome or decrease this problem. Molecular docking study shows that FON is missing a crucial stabilizing interaction with the key amino acid Asp98 causing a reduced activity at hH2R receptor relative to FAM. Moreover, ADMET properties prediction revealed some differences in the toxicity, pharmacokinetics, metabolism, and solubility profiles of FAM and FON.

Development and validation of RP-HPLC method for simultaneous determination of cefpodoxime proxetil and H2 receptor antagonists in pharmaceutical dosage forms.

A new method on RP-HPLC is devised and validated, as per ICH guidelines, for the synchronous estimation of cefpodoxime proxetil and H2-receptor antagonits that are Cimetidine, Famotidine and Ranitidine. The method is simple, accurate, expeditious, reproducible, robust and precise. Chromatography was done on a C18 (250 x 4.6mm) column with methanol: water as mobile phae in the ratio of 70:30 (v/v), pumped at a flow rate of 1ml/min and pH was maintained using 85% ortho-phosphoric acid at 3. The λ max 240 nm was preferred for UV detection. A good linear relationship was attained, over the concentration ranges of 20-70 µg/ml and 5-30µg/ml, for cefpodoxime proxetil and H2 blockers respectively, with a correlation coefficient of R= 0.9987 to 0.9992. The method was validated and found precised (i.e. intra day and interday analysis) with RSD <2%. LOD and LOQ observations were under 0.4806 to 2.6069µg/ml which proved the method to be sensitive. The method provided satisfactory results of robustness and reproducibility, when validated and applied successfully for analysis of dosage forms.

Application of polyacrylonitrile nanofibers decorated with magnetic carbon dots as a resonance light scattering sensor to determine famotidine.

In this study, a novel resonance light scattering (RLS) sensor was synthesized using polyacrylonitrile nanofibers decorated with magnetic carbon dots (MCDs@NFs) nanocomposite and applied for famotidine (FMD) determination. The MCDs@NFs nanocomposite was synthesized by combining electrospinning and a simple one-step hydrothermal method. Different methods were applied in order to characterize the MCDs@NFs nanocomposite such as: scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FT-IR), Transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), and X-ray diffraction (XRD). Light scattering properties of the synthesized nanocomposite in the presence or absence of FMD have been selected as the detection signal considering the fact that FMD addition increases the RLS intensities of the system. Thus, the prepared nanocomposite was employed as a RLS sensor to detect FMD. A linear response was observed under the optimal conditions in range of 0.15-50.0µmolL-1 with detection limit of 0.04µmolL-1. The MCDs@NFs nanocomposite was effectively capable in determining FMD in real samples and the results were close to those results obtained by reversed-phase HPLC method (RP-HPLC).

Multivariate Validated Models for Simultaneous Determination of Ibuprofen and Famotidine in the Presence of Related Substances.

Two multivariate validated spectrophotometric methods, namely partial least-squares (PLS) and principal component regression (PCR), were developed and validated for the determination of ibuprofen and famotidine in presence of famotidine degradation products and ibuprofen impurity (4-isobutylacetophenone). A calibration set was prepared in which the two drugs together with the degradation products and impurity were modeled using a multilevel multifactor design. This calibration set was used to build the PLS and PCR models. The proposed models successfully predicted the concentrations of both drugs in validation samples, with low root mean square error of cross validation (RMSECV) percentage. The method was validated by the estimate of the figures of merit depending on the net analyte signal. The results of the two models showed that the simultaneous determination of both drugs could be performed in the concentration ranges of 100-500 µg/mL for ibuprofen and 5-25 µg/mL for famotidine. The proposed multivariate calibration methods were applied for the determination of ibuprofen and famotidine in their pharmaceutical formulation, and the results were verified by the standard addition technique.

Development of a Validated Comparative Stability-Indicating Assay Method for Some H2-Receptor Antagonists.

A comparative force degradation high performance thin layer chromatography (HPTLC) method was developed and validated for some H2-receptor antagonists. The studied H2-receptor antagonists were ranitidine (RAN), nizatidine (NIZ) and famotidine (FAM). The degradation behaviors of the studied H2-receptor antagonists were studied under different stress conditions (hydrolytic, thermal and oxidative) conditions as well as storage conditions according to International Conference on Harmonization (ICH) recommendations. A stability-indicating HPTLC method was optimized in order to separate the analyte from the degradation products formed under various stress conditions. Full separation of the drugs from their degradation products was successfully achieved on an HPTLC precoated silica gel plates. Densitometric measurements were carried out using a Camag TLC Scanner III in the absorbance mode at 320 nm for RAN and NIZ, and 280 nm for FAM. The limits of detection and limits of quantitation range were 5.47-9.37 and 16.30-31.26 ng/band, respectively, for all investigated drugs. The validation studies were performed according to ICH requirements. The developed method was simple, rapid and reliable hence it could be applied for routine quality control analysis of the investigated H2-receptor antagonists in dosage forms. The kinetic behavior, degradation rate constants and half-lives of the degradation of the investigated drugs were studied and compared at different stress conditions. The present study provides, for the first time, a new vision to compare the degradation kinetics of H2-receptor antagonists at the same degradation procedures.

Development and validation of chromatographic methods for simultaneous determination of ibuprofen and famotidine in presence of related substances in pharmaceutical formulations.

Two validated methods for the simultaneous determination of ibuprofen and famotidine in the presence of ibuprofen impurity (4-isobutylacetophenone) and or famotidine degradation products were described. The first method was a simple TLC method where separation was performed on silica gel platesusing ethyl acetate: methanol: ammonia (9:2:1, by volume) as a mobile phase. Rf values were found to be 0.40, 0.94, 0.66, 0.27, 0.83 for ibuprofen, 4-isobutylacetophenone, famotidine, famotidine acid and basic degradation products, respectively. The second method is by HPLC on C18 column using methanol: phosphate buffer pH 3 (80:20, v/v) as a mobile phase. Retention times were found to be 2.2, 9.9, and 8.6 for famotidine, ibuprofen, and 4-isobutylacetophenone, respectively. Both methods were validated according to the ICH guidelines and applied for the determination of the two drugs in pure powder and combined dosage form without interference from the excipients.

Application of the ratio difference spectrophotometry to the determination of ibuprofen and famotidine in their combined dosage form: comparison with previously published spectrophotometric methods.

Ratio difference spectrophotometric method was developed for the determination of ibuprofen and famotidine in their mixture form. Ibuprofen and famotidine were determined in the presence of each other by the ratio difference spectrophotometric (RD) method where linearity was obtained from 50 to 600µg/mL and 2.5 to 25µg/mL for ibuprofen and famotidine, respectively. The suggested method was validated according to ICH guidelines and successfully applied for the analysis of ibuprofen and famotidine in their pharmaceutical dosage forms without interference from any additives or excipients.

Spectrofluorimetric analysis of famotidine in pharmaceutical preparations and biological fluids by derivatization with benzoin.

A sensitive and simple spectrofluorimetric method has been developed for the analysis of famotidine, from pharmaceutical preparations and biological fluids after derivatization with benzoin. The reaction was carried out in alkaline medium with measurement of fluorescence intensity at 446 nm with excitation wavelength at 286 nm. Linear calibration was obtained with 0.5-15 µg/ml with coefficient of determination (r(2)) 0.997. The factors affecting the fluorescence intensity were optimized. The pharmaceutical additives and amino acid did not interfere in the determination. The mean percentage recovery (n=4) calculated by standard addition from pharmaceutical preparation was 94.8-98.2% with relative standard deviation (RSD) 1.56-3.34% and recovery from deproteinized spiked serum and urine of healthy volunteers was 98.6-98.9% and 98.0-98.4% with RSD 0.34-0.84% and 0.29-0.87% respectively.

Derivative emission spectrofluorimetry: Application to the analysis of newly approved FDA combination of ibuprofen and famotidine in tablets.

A new combination of ibuprofen (NSAID) and famotidine (H2 receptor antagonist) was recently approved by the FDA. It was formulated to relief pain while decreasing the risk of ulceration, which is a common problem for patients receiving NSAID. A rapid and simple derivative emission spectrofluorimetric method is proposed for the simultaneous analysis of this combination in their pharmaceutical preparation. The method is based upon measurement of the native fluorescence intensity of the two drugs at λex = 233 nm in acetonitrile. The emission data were differentiated using the first (D1) derivative technique. The plots of derivative fluorescence intensity versus concentration were rectilinear over a range of 2-35 and 0.4-8 µg/mL for both ibuprofen (IBU) and famotidine (FAM), respectively. The method was sensitive as the limits of detection were 0.51 and 0.12 µg/mL and limits of quantitation were 1.70 and 0.39 µg/mL, for IBU and FAM respectively. The proposed derivative emission spectrofluorimetric method was successfully applied for the determination of the two drugs in their synthetic mixtures and tablets with good accuracy and precision. The proposed method was validated as per ICH guidelines.

Validated HPTLC method for simultaneous quantitation of paracetamol, diclofenac potassium, and famotidine in tablet formulation.

A sensitive, simple, selective, precise, and accurate HPTLC method of analysis for paracetamol, diclofenac potassium, and famotidine both as a bulk drug and in tablet formulation was developed and validated. The method used HPTLC aluminum plates precoated with silica gel 60F254 as the stationary phase, and the mobile phase consisted of toluene-acetone-methanol-formic acid (5 + 2 + 2 + 0.01, v/v/v/v). Densitometric evaluation of the separated zones was performed at 274 nm. This system was found to give compact spots for paracetamol (Rf value = 0.62 +/- 0.03), diclofenac potassium (0.75 +/- 0.02), and famotidine (0.17 +/- 0.03). The linear regression analysis data for the calibration plots showed a good linear relationship over the concentration range of 1625-9750 ng/spot for paracetamol, 250-1500 ng/spot for diclofenac potassium, and 100-600 ng/spot for famotidine. The method was validated for precision, robustness, and recovery according to International Conference on Harmonization guidelines. No chromatographic interference from the tablet excipients was found. Statistical analysis showed that the method was repeatable and selective for the simultaneous quantitation of the three drugs in tablet formulation and for routine quality control of raw materials of the drugs.

Rietveld refinement in the routine quantitative analysis of famotidine polymorphs.

Accurate, precise and reliable X-ray powder diffraction method was developed for the quantitative determination of famotidine polymorphic forms in their binary mixtures, which slightly outperforms the previously established Raman method. The study highlights the advantage of focused beam transmission geometry in diminishing the effect of preferred orientation in general, and the straightforward transmission foil sample preparation technique in facilitating high-throughput measurements in particular. This combination can provide good quality data for Rietveld refinement which assures more reliable quantitative results than utilizing intensity ratios of selected single reflections. After careful adjustment of profile parameters, simple routine application of the method was achieved.

Prediction of the stability of polymeric matrix tablets containing famotidine from the positron annihilation lifetime distributions of their physical mixtures.

The aim of the present work was to elucidate the impact of the structural changes of polymeric excipients during the course of storage on the drug release stability of tablets containing different polymers. Matrix tablets were formulated with famotidine as a model drug, using polyvinylpyrrolidone and carbopol matrix. Dissolution tests were carried out before and after storing the tablets under stress conditions for different time intervals. Parameters characterizing the release kinetics of matrix tablets, just as difference and similarity factors, were calculated to compare the release profiles as a function of storage time. Positron annihilation lifetime measurements were carried out to track the structural changes of the physical mixtures containing polymers during the course of storage. The changes in the positron lifetime distribution curves of the famotidine-polymer mixtures were in good correlation with the significant changes of release parameters of tablets. Thus the method would be a valuable tool for the screening of possible destabilizing interactions in the preformulation phase.

Quantitative determination of famotidine polymorphs: X-ray powder diffractometric and Raman spectrometric study.

X-ray powder diffractometric and Raman spectrometric methods were developed for quantitative measurement of the polymorphic forms of famotidine in their mixtures. This study aims to deduce some useful conclusions regarding quantitative polymorph analysis, which could also be utilized in industrial practice. Both form A and form B of famotidine possess specific X-ray diffraction reflections as well as characteristic Raman vibrational bands, which permits simple determination of the phases in their mixtures. Keeping in mind that multivariate data processing by chemometric approach is thought of nowadays as superior over univariate one, the results of the two evaluation methods were compared by precision, accuracy as well as robustness. It was found that both approaches provide similar results provided analytically useful data regions are properly selected. Overcoming the common problems of quantitative X-ray powder diffractometry and solid state Raman spectrometry both permit accurate quantification of famotidine polymorphs; the latter, however, seems to be more favourable in regular laboratory practice.

Spectrofluorimetric determination of famotidine in pharmaceutical preparations and biological fluids. Application to stability studies.

A simple, economic, selective, and stability indicating spectrofluorimetric method was developed for the determination of famotidine (FMT); is based on its reaction with 9, 10-phenanthraquinone in alkaline medium to give a highly fluorescent derivative measured at 560 nm after excitation at 283 nm. The fluorescence intensity-concentration plot was rectilinear over the concentration range of 50-600 ng/ml with minimum quantification limit (LOQ) of 13.0 ng/ml and minimum detection limit (LOD) of 4.3 ng/ml. The factors affecting the development of the fluorescence intensity of the reaction product were carefully studied and optimized. The method was applied for the determination of FMT in its dosage forms. The stability of the compound was studied, and the proposed method was found to be stability indicating one. The results obtained were in good agreement with those obtained by the official method. Furthermore, the method was applied for the determination of FMT in spiked and real human plasma. The mean % recovery (n = 4) was found to be 99.94 +/- 0.24, and 105.13 +/- 0.64 for spiked and real human plasma, respectively. The composition of the reaction product as well as its stability constant was also investigated. Moreover, the method was utilized to investigate the kinetics of both alkaline and oxidative induced degradation of the drug. The apparent first order rate constant and half life time of the degradation product was calculated. A proposal of the reaction pathway was postulated.

Capillary zone electrophoresis method for the determination of famotidine and related impurities in pharmaceuticals.

A simple and rapid capillary zone electrophoresis (CZE) method with UV detection has been developed for the determination of famotidine and its potential impurities in pharmaceutical formulations. The electrophoretic separation of these compounds was performed using a fused silica capillary and 37.5mmolL(-1) phosphate buffer pH 3.5 as the electrolyte. Under the optimised conditions, six impurities could be resolved from the famotidine peak in less than 7min. The calibration curves obtained for the seven compounds were linear over the concentration range investigated (from 1.5 to 78.5microg mL(-1)). The intra- and inter-day relative standard deviations for the migration times and corrected peak areas were less than 2% and 5%, respectively. The detection limits were found to be 0.09microg mL(-1) for famotidine, and from 0.1 to 0.62microg mL(-1) depending on the impurities. The method has been successfully applied to the determination of famotidine in commercial dosage forms.

Spectrophotometric determination of H(2)-receptor antagonists via their oxidation with cerium(IV).

A simple, accurate and sensitive spectrophotometric method has been developed and validated for determination of H(2)-receptor antagonists: cimetidine, famotidine, nizatidine and ranitidine hydrochloride. The method was based on the oxidation of these drugs with cerium(IV) in presence of perchloric acid and subsequent measurement of the excess Ce(IV) by its reaction with p-dimethylaminobenzaldehyde to give a red colored product (lambda(max) at 464nm). The decrease in the absorption intensity of the colored product (DeltaA), 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 the optimum conditions, linear relationships with good correlation coefficients (0.9990-0.9994) were found between DeltaA values and the concentrations of the drugs in a concentration range of 1-20microgml(-1). The assay limits of detection and quantitation were 0.18-0.60 and 0.54-1.53microgml(-1), 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 determination of the investigated drugs in pure and pharmaceutical dosage forms (recovery was 98.3-102.6+/-0.57-1.90%) without interference from the common excipients. The results obtained by the proposed method were comparable with those obtained by the official methods.

A new sensitive flow-injection chemiluminescence method for the determination of H(2)-receptor antagonists.

Based on the chemiluminescence (CL) intensity generated from the potassium ferricyanide [K(3)Fe(CN)(6)]-rhodamine 6G system in sodium hydroxide (NaOH) medium, a new sensitive flow-injection chemiluminescence (FI-CL) method has been developed, validated and applied for the determination of three kinds of H(2)-receptor antagonists: cimetidine (CIMT), ranitidine (RANT) hydrochloride and famotidine (FAMT). Under the optimum conditions, the linear range for the determination was 1.0 x 10(-9)-7.0 x 10(-5) g/ml for CIMT, 1.0 x 10(-9)-5.0 x 10(-5) g/mL for RANT hydrochloride and 5.0 x 10(-9)-7.0 x 10(-5) g/mL for FAMT. During 11 repeated measurements of 1.0 x 10(-6) g/mL sample solutions, the relative standard deviations (RSDs) were all <5%. The detection limit was 8.56 x 10(-10) g/mL for CIMT, 8.69 x 10(-10) g/mL for RANT hydrochloride and 2.35 x 10(-9) g/mL for FAMT (S:N = 3). This method has been successfully implemented for the analysis of H(2)-receptor antagonists in pharmaceuticals.