Spectrophotometric and Spectrofluorimetric Determination of Famotidine and Ranitidine Using 1,4-Benzoquinone Reagent

ABSTRACT

Spectrophotometric and spectrofluorimetric methods were adopted for the analysis of Famotidine and Ranitidine depending on their reaction with 1,4 Benzoquinone reagent at pH 5.2 and 5.6, respectively. The absorbances of the resulting condensation products were measured at 502 and 508 nm for Famotidine and Ranitidine, respectively. Concentrations adhering to Beer's law were from 40-160 μg.ml^? for Famotidine and from 20-100 μg.ml^? for Ranitidine.

Furthermore the resulting condensation products exhibited fluorescence at 665 nm when excited at 290 nm and the calibration graphs were rectilinear from 0.4-1.4 μg.ml^? for Famotidine and from 0.21 μg.ml^? for Ranitidine.

Different parameters affecting these reactions were thoroughly studied. Also these methods were applied to the pharmaceutical preparations and the results were satisfactory. The validities of the methods were ascertained by the standard addition technique revealing fine results in consideration to the mean recovery percent and standard deviation.

The spectrofluorimetric method was a hundred times more sensitive then the spectrophotometric method. The proposed methods were sensitive, accurate, and precise as statistically compared with the official methods of analysis of Famotidine and Ranitidine.     

七、八元瓜环对盐酸雷尼替丁的包合作用及缓释性能

研究了七元瓜环(Q[7])和八元瓜环(Q[8])与盐酸雷尼替丁(RH)的包合作用及包合物的体外药物缓释性能.采用紫外-可见光谱法测定了体系的包合比、包合稳定常数和药物累积释放度;用1H NMR技术考察了体系主-客体的包合作用.结果表明,Q[7]和Q[8]与RH在酸性及中性条件下均能发生1∶1包合作用,包合稳定常数分别为1.21×104和2.06×104 L/mol;在碱性条件下则不发生包合作用.原药RH,Q[7]-RH及Q[8]-RH包合物在人工胃液(pH=1.2)中的60 min累积释放度分别为89.1%,56.6%和38.4%;而在人工肠液(pH=6.8)中三者的60 min累积释放度分别为90.2%,58.7%和38.0%.实验结果表明,Q[7]及Q[8]包合对RH有明显的体外缓释作用.     

HPLC separations of meropenem and selected pharmaceuticals using a polar endcapped octadecylsilane narrow bore column

Summary Stability indicating high performance liquid chromatography methods have been developed for the assay of meropenem in combination with either dopamine (A), aminophylline (B), metoclopramide (C) or ranitidine (D) in intravenous fluid mixtures. Separations B, C and D were performed on a polar endcapped ODS column (150×2 mm) with aqueous, pH 3.0—acetonitrile (89∶11, 88∶12, and 92∶8) eluent and detection at 270, 290, 317 nm respectively. Meropenem was linear over the concentration ranges 126.88–507.50, 131.25–525, and 131.25–525 gmg mL⁻¹. Aminophylline, metoclopramide and ranitidine were linear over the concentration ranges 13–52, 37.5–150, and 25–100 μg mL⁻¹. Separation A was performed on a conventional ODS column (150×2.1 mm) with aqueous, pH 3.0—acetonitrile (85∶15) eluent and detection at 280 nm. Meropenem and dopamine were linear in the 61.25–245 and 10–40 μg mL⁻¹ ranges, respectively. Accuracy and precision for all methods were 0.20–3.30% and 0.10–1.58%, respectively. Accelerated stability studies have been carried out on each drug by exposure to acid, base, H₂O₂, and heat for different time periods.     

Rapid determination of ranitidine in human plasma by high-performance liquid chromatography

Summary An HPLC method has been developed for the quantification of rantidine in plasma for pharmacokinetic studies. Metoclopramide was used as internal standard. The method uses a simple and rapid sample clean-up procedure involving single-step extraction with organic solvent to extract ranitidine from plasma. After evaporation and reconstitution the samples are chromatographed on a 250 mm×4 mm base-stable reversed-phase column with 0.05 M ammonium acetate-acetonitrile, 75∶25 (v/v) as mobile phase and UV detection at 313 nm. The calibration graph was linear for quantities of ranitidine between 10 and 2000 ng mL⁻¹. Intra- and inter-dayCV did not exceed 11.64%. The quantitation limit was 10 ng mL⁻¹ for human plasma. The applicability of this method for pharmacokinetic studies of ranitidine after oral administration are described. Approximately 90 samples can be processed in 24 h.     

On-line solution stability determination of pharmaceuticals by capillary electrophoresis

Summary Good agreement between the impurity levels in a batch of a related impurity of ranitidine were obtained by CE and HPLC. A solution of the impurity was positioned on the CE autosampler and analysed sequentially. The extent of degradation was monitored by loss of main peak and the formation of two principal degradation products. It was found that after 9.25 hours only 2% area/area of the original impurity remained. Buffering of the sample solution to pH 7 was shown to minimise this degradation.Unattended in-situ stability testing of an solution of the impurity in water was performed by CE.     

Study of the reactions of cisplatin with ranitidine and nizatidine by means of 1H NMR spectroscopy in D2O

The reactions of cisplatin with nizatidine and ranitidine were studied in D₂O at pD 7.4 and 298 K by means of ¹H NMR spectroscopy. The second order rate constants, k ₂, for the reaction of cisplatin with nizatidine is (2.71 ± 0.11) × 10⁻⁴ M ⁻¹ s⁻¹, and for the reaction with ranitidine (6.72 ± 0.17) × 10⁻⁴ M ⁻¹ s⁻¹. The reactions of nizatidine and ranitidine were also studied with other Pd(II) and Pt(II) complexes. The set of the complexes was selected because of their difference in reactivity, steric hindrance, and binding properties. Correspondence: Prof. Dr. Živadin D. Bugarčić, Faculty of Science, University of Kragujevac, Radoja Domanovića 12, 34000 Kragujevac, Serbia.     

盐酸雷尼替丁分子模板聚合物的分子识别特性

采用分子印迹技术合成了对药物雷尼替丁有高度选择性的模板聚合物。通过Scatchard方程和紫外光谱分析研究了模板聚合物的结合特性。结果表明,其结合位点的解离常数为Kd=2.679×10-3mol/L。底物的选择性结合实验表明,其模板聚合物对盐酸雷尼替丁有较大的吸附性和高度的选择性及识别能力。     

雷尼替丁离子选择性电极聚氯乙烯敏感膜的质谱与电镜剖析

本文用质谱法分析了雷尼替丁与四苯硼钠沉淀生成的电活性物质的组成。对PVC敏感膜进行电镜剖析,表明成膜过程对电极性能的影响有关。     

枸橼酸铋雷尼替丁胶囊有效成份的紫外分光光度法的测定

提出了对枸橼酸铋雷尼替丁胶囊有效成份进行紫外分光光度测定的新方法，该方法简便、快速、准确度高，能用于纯度较高的样品分析，可作为枸橼酸铋雷尼替丁胶囊药品质量标准控制方法。     

Simultaneous Determination of Ranitidine and Metronidazole at Glassy Carbon Electrode Modified with Single Wall Carbon Nanotubes

Single‐walled carbon nanotubes(SWCNTs) were dispersed into DMSO, and a SWCNTs‐film coated glassy carbon electrode was achieved via evaporating the solvent. The results indicated that CNT modified glassy carbon electrode exhibited efficiently electrocatalytic reduction for ranitidine and metronidazole with relatively high sensitivity, stability and life time. Under conditions of cyclic voltammetry, the potential for reduction of selected analytes is lowered by approximately 150 mV and current is enhanced significantly (7 times) in comparison to the bare glassy carbon electrode. The electrocatalytic behavior is further exploited as a sensitive detection scheme for these analytes determinations by hydrodynamic amperometry. Under optimized condition in amperometric method the concentration calibration range, detection limit and sensitivity were about, 0.1–200 μM, detection limit (S/N=3) 6.3×10^?8 mol L^?1 and sensitivity 40 nA/μM for metronidazole and 0.3–270 μM 7.73×10^?8 mol L^?1 and 25 nA/μM for ranitidine. In addition, the ability of the modified electrode for simultaneous determination of ranitidine and metronidazole was evaluated. The proposed method was successfully applied to ranitidine and metronidazole determination in tablets. The analytical performance of this sensor has been evaluated for detection of these analytes in serum as a real sample.