Modified Spectrophotometric Method for the Determination of Some Important Antibiotics Through Charge - Transfere Complexation Reaction with Chloranil

Abstract

A new modified Spectrophotometric procedures are presented for the determination of three pharmaceutical antibiotic compounds through charge-transfere complexation reaction with chloranil. The complex shows an absorption mAxima at 550 nm, having a molar absorptivity coefficient of 5.55×10³,7.81×10³ and 1.38×10⁴ 1. mol^?1cm^?1 for ampicillin, amoxycillin and neomycin, respectively. Optimization of the reaction conditions has been investigated Obediance to Beer's law (40μg/ml) permitted the assay of thes drugs in its dosage forms A variety of pharmaceutical dosage forms containing ampicillin, amoxycillin and neomycin are successfully analysed by the proposed procedure.     

A Simple and Sensitive Spectrofluorimetric Method for Analysis of Some Nitrofuran Drugs in Pharmaceutical Preparations

A simple, rapid, selective and sensitive spectrofluorimetric method was described for the analysis of three nitrofuran drugs, namely, nifuroxazide (NX), nitrofurantoin (NT) and nitrofurazone (NZ). The method involved the alkaline hydrolysis of the studied drugs by warming with 0.1 M sodium hydroxide solution then dilution with distilled water for NX or 2-propanol for NT and NZ. The formed fluorophores were measured at 465 nm (λ _Ex 265 nm), 458 nm (λ _Ex 245 nm) and 445 nm (λ _Ex 245 nm) for NX, NT and NZ, respectively. The reaction pathway was discussed and the structures of the fluorescent products were proposed. The different experimental parameters were studied and optimized. Regression analysis showed good correlation between fluorescence intensity and concentration over the ranges 0.08–1.00, 0.02–0.24 and 0.004–0.050 μg ml⁻¹ for NX, NT and NZ, respectively. The limits of detection of the method were 8.0, 1.9 and 0.3 ng ml⁻¹ for NX, NT and NZ, respectively. The proposed method was validated in terms of accuracy, precision and specificity, and it was successfully applied for the assay of the three nitrofurans in their different dosage forms. No interference was observed from common pharmaceutical adjuvants. The results were favorably compared with those obtained by reference spectrophotometric methods.     

Spectrophotometric Determination of Pyrithioxin in Pharmaceutical Preparations

Rapid direct and induced difference spectrophotometric methods for determination of pyrithioxin in single dosage forms (tablets and syrups) are reported. The direct methods depend upon measurement of the absorbance of pyrithioxin in different media at λ_max i-e at 296 nm in 0.1 M hydrochloric acid, at 328 nm in citric acid-phosphate buffer of pH 7 and at 314 nm in 0.1 M sodium hydroxide. The mean percentage recovery of the authentic samples were 100.55±0.43, 101.21±0.58 and 100.29±0.64 respectively (P=0.05). The absorbance difference methods are based upon either measurement of the difference between the acid and the alkaline solutions i-e. Δ A (Alk-Acid) at 318 nm with an accuracy of 100.72±0.88 or the absorbance difference between the acid and neutral solutions i-e Δ A (pH 7-acid) at 328 nm with an accuracy of 100.31±0.68.     

Spectrofluorimetric Method for Determination and Validation of Cefixime in Pharmaceutical Preparations Through Derivatization with 2-Cyanoacetamide

A simple, sensitive and accurate method has been developed for spectrofluorimetric determination of cefixime in pure form and pharmaceutical preparations. The method is based on the reaction of cefixime with 2-cyanoacetamide in the presence of 21% ammonia at 100 °C. The fluorescent reaction product showed maximum fluorescence intensity at λ 378 nm after excitation at λ 330 nm. The factors affecting the derivatization reaction were carefully studied and optimized. The fluorescence intensity versus concentration plot was rectilinear over the range of 0.02 to 4 μg mL⁻¹ with correlation coefficient of 0.99036. The limit of detection (LOD) and limit of quantification (LOQ) was found to be 2.95 ng mL⁻¹ and 9.84 ng mL⁻¹, respectively. The proposed method was validated statistically and through recovery studies. The method was successfully applied for the determination of cefixime in pure and dosage form with percent recoveries from 98.117% to 100.38%. The results obtained from the proposed method have been compared with the official HPLC method and good agreement was found between them.     

A Validated High-Throughput Fluorometric Method for Determination of Omeprazole in Quality Control Laboratory via Charge Transfer Sensitized Fluorescence

A high-throughput 96-microwell plate fluorometric method was developed and validated to determine omeprazole (OMZ) in its dosage forms. The method was based on the charge-transfer (CT) sensitized fluorescence reaction of OMZ with 2, 3-dichloro-5, 6-dicyano-1, 4-benzoquinone (DDQ). This fluorescence reaction provided a new approach for simple, sensitive and selective determinations of OMZ in pharmaceutical preparations. In the present method, the fluorescence reaction was carried out in 96-microwell plates as reaction vessels in order to increase the automation of the methodology and the efficiency of its use in quality control laboratories. All factors affecting the fluorescence reaction were carefully studied and the conditions were optimized. The stoichiometry of the fluorescence reaction between OMZ and DDQ was determined and the reaction mechanism was suggested. Under the optimum conditions, the linear range was 100–6000 ng/ml with the lowest LOD of 33 ng/ml. Analytical performance of the proposed assay, in terms of accuracy and precision, was statistically validated and the results were satisfactory; RSD was <2.6 % and the accuracy was 98.6–101.6 %. The method was successfully applied to the analysis of OMZ in its dosage forms; the recovery values were 98.26–99.60 ± 0.95–2.22 %. The developed methodology may provide a safer, automated and economic tool for the analysis of OMZ in quality control laboratories.     

Spectrofluorometric Determination of Methocarbamol in Pharmaceutical Preparations and Human Plasma

A simple, sensitive and rapid spectrofluorometric method for determination of methocarbamol in pharmaceutical formulations and spiked human plasma has been developed. The proposed method is based on the measurement of the native fluorescence of methocarbamol in methanol at 313 nm after excitation at 277 nm. The relative fluorescence intensity-concentration plot was rectilinear over the range of 0.05–2.0 μg/mL, with good correlation (r = 0.9999), limit of detection of 0.007 μg/ mL and a lower limit of quantification of 0.022 μg/ mL. The described method was successfully applied for the determination of methocarbamol in its tablets without interference from co-formulated drugs, such as aspirin, diclofenac, paracetamol and ibuprofen, The results obtained were in good agreement with those obtained using the official method (USP 30).The high sensitivity of the method allowed the determination of the studied drug in spiked human plasma with average percentage recovery of 99.42 ± 3.84.     

磷钨钒杂多酸-TMBPS电荷转移配合物光度法测定钒

提出了一种基于形成磷钨钒杂多酸 3,3′,5 ,5′ 四甲基联苯胺 -丙磺酸 (TMBPS)电荷转移配合物的分光光度法测定钒 (Ⅴ )的新方法 ,其最大吸收波长为 45 0nm ,摩尔吸光系数 2 74× 10 4 L·mol-1·cm-1,线性范围 0 0 2～ 1μg·mL-1。采用浮选反萃取分光光度法 ,可提高测定灵敏度 ,其表观摩尔吸光系数增至 3 10×10 5L·mol-1·cm-1。     

PMR Spectrometric Analysis of Stilbestrol and Some of Its Pharmaceutical Preparations

A novel method is developed using PMR technique for quantitative determination of stilbestrol and some of its pharmaceutical preparations. The method developed is accurate, rapid, and precise. It involves comparing the integral of the nice triplet system of stilbestrol spectrum (positioned at 0.73 δ) to that of the sharp singlet signal (positioned at 6.25 δ) of maleic acid which is used as internal standard.     

Aq++H碰撞中的电荷转移

利用CTMC方法计算C^q+,N^q+,O^q+与H原子的碰撞过程的截面.入射粒子的能量范围为10~250keV/amu,离子为部分电离和完全电离的离子.给出了十二个耦合的Hamilton运动方程.用六个伪随机数确定粒子的轨道. A^q+离子和作用电子的势为模型势,其他两个势为纯库仑势。在计算中,需要2000个以上的轨道.引入约化变量σ_tr=σ_tr/q,E=E/q^1/2,得到了q标度的俘获截面,这些截面数据都集中在一条曲线附近.计算结果与其他理论计算结果作了比较,它们符合得很好.     

磷酸盐的电荷转移反应分光光度法测定

基于磷钼杂多酸与３,３’５,５’－四 苯胺形成黄色的电荷转移配合物,本文提出了一种新的测定磷酸盐的方法,其最大吸收波长为４５０ｎｍ,摩尔吸光系数为１．０８＊１０＾４Ｌ．ｍｏｌ＾－１．ｃｍ＾－１,本方法用于样品中磷酸盐的测定,结果令人满意。     

Fluorometric Determination of Bopindolol and Celiprolol in Pharmaceutical Preparations and Biological Fluids

Two sensitive fluorometric methods were developed for the determination of both bopindolol malonate (BOP) and celiprolol HCl (CLP) based on measuring their native fluorescence in methanol and acetonitrile, respectively. For BOP, the fluorescence was measured at 316?nm after excitation at 278?nm. The proposed method was successfully applied to the assay of commercial tablets as well as content uniformity testing. For CLP, the fluorescence was enhanced by the addition of carboxymethylcellulose solution and measured at 455?nm after excitation at 339?nm. The method was successfully applied to the analysis of CLP in tablets and biological fluids. In both methods, interference likely to be introduced from co-formulated, co-administered, or chemically related drugs was studied. The results were statistically compared with those obtained by reference methods and were found to be in good agreement.     

Application of PMR Spectrometry in Quantitative Analysis of Tiaprofenic Acid in Some Pharmaceutical Preparations

A simple, accurate and specific proton magnetic resonance (PMR) procedure was developed for the assay of tiaprofenic acid and its tablets. The method involves comparing the integral of the nice doublet signal of tiaprofenic acid (positioned at 1.60 δ) to that of the sharp singlet signal (positioned at 2. 1 δ) of acetanilide which is used as internal standard. The method reported in this study gives accurate and reproducible results; 100. 16 ± 0. 23% for authentic tiaprofenic acid and 100.00 ± 1. 05% for tiaprofenic acid tablets (Surgam^R). In addition, the PMR spectrum obtained helps in confirming the identify and purity of the drug.     

A Validated Spectrofluorimetric Method for the Determination of Citalopram in Bulk and Pharmaceutical Preparations Based on the Measurement of the Silver Nanoparticles-Enhanced Fluorescence of Citalopram/Terbium Complexes

A simple, sensitive, and accurate spectrofluorimetric method was developed for the determination of citalopram in bulk and pharmaceutical preparations. The method is based on the enhancement of the weak fluorescence signal (FL) of the Tb (III)-citalopram system in the presence of silver nanoparticles. Fluorescence intensities were measured at 555 nm after excitation at 281 nm. Prepared silver nanoparticles (AgNPs) were characterized by UV-Visible spectra and transmission electron microscopy (TEM). Various factors affecting the formation of citalopram-Tb (III)-AgNPs complexes were studied and optimized. The fluorescence intensity versus concentration plot was linear over the range 0.02–14 μg?mL^?1, with an excellent correlation coefficient of 0.9978. The limit of detection (LOD) and limit of quantification (LOQ) were found to be 7.15?×?10^?6?μg?mL^?1 and 2.38?×?10^?5?μg?mL^?1 respectively. The proposed method was found to have good reproducibility with a relative standard deviation of 3.66 % (n?=?6). The interference effects of common excipients found in pharmaceutical preparations were studied. The developed method was validated statistically by performing recoveries studies and successfully applied for the assay of citalopram in bulk powder and pharmaceutical preparations. Percent recoveries were found to range from 98.98 % to 100.97 % for bulk powder and from 96.57 % to 101.77 % for pharmaceutical preparations.     

缬氨酸的荷移分光光度法测定

研究了缬氨酸与四氯对苯醌(TCBQ)的荷移反应,确立了荷移反应的最佳条件。实验表明,在水溶液中,两者在50℃水浴中恒温70min,即可形成2∶1型的稳定络合物,其最大吸收波长λmax=350nm,表观摩尔吸光系数ε=4.7×104L·mol-1·cm-1,在0—6.7μg/mL范围内符合比耳定律,方法的相对标准偏差小于1.2%。方法对样品含量测定,结果与文献方法一致。     

荷移荧光光谱法测定加替沙星

研究了加替沙星(GFLX) 与电子受体四氯对苯醌(TCBQ)之间的荷移反应,建立了测定加替沙星的新方法。实验结果表明,在甲醇-水介质中于45 ℃水浴恒温20 min,GFLX与TCBQ可形成稳定的1∶1电荷转移络合物,其荧光发射强度较GFLX本身有显著的增强。在0.19～5.6 mg·L-1 浓度范围内,荧光强度与GFLX浓度呈良好的线性关系,检出限为0.005 6 mg·L-1。用于药物制剂中GFLX的含量测定,其回收率为101.1%～103.9%;标准偏差为1.0%～1.9%。同时建立了测定尿样中GFLX的荷移同步荧光光谱法,GFLX浓度在0.023～3.4 mg·L-1范围内与荧光强度呈良好的线性关系,检出限为0.003 4 mg·L-1。用本方法测定尿液中的GFLX,结果与文献值基本一致,回收率为93.9%～101.0%;标准偏差为1.0 %～1.7%。     

Radiophotolumenescence of Irradiated Polymethylmethacrylate Doped with Some Charge Transfer Complexes

Radiophotolumenescence (RPL) of irradiated and non irradiated thin films of polymethylmethacrylate (PMMA) doped with anthracene (Anth) as a donor, and tetracyanoquinodimethane (TCNQ) as an acceptor, has been investigated. The RPL – glow spectrum was recorded to study the characterizing emission bands from the point of view of glow peak position and intensity and hence the prospective relative sensitivities. RFL – signal fading after one month storage in dark at room temperature post gamma irradiation was also studied. PMMA doped with 6:4 donor to acceptor ratio has been proved to be the most sensitive one with less fading regarding gamma detection. On the other hand 2 Anth: 8 TCNQ was found to be the proper dopant concentration ratio for thermal neutron detection.     

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.     

Spectroscopic and Conductive Properties of Some Charge Transfer Complexes of Iodine

Abstract

The interaction of iodine with donor bases such as neutral red (NR) and 1, 10 -phenanthroline (Ph) have been studied spectrophotometrically in C₂H₅OH. The results indicate the formation of 2:3 charge transfer complexes of the type (base)₂3I₂. Mass, Raman and ¹H NMR spectra have been recorded for each complex. I₃ ^? and I₂ species are observed in these complexes. In addition, the d.c. conductivity is measured in the range (300–400) K°. The energy gap of the ionic conduction has been calculated. The conduction process is thought to involve iodide transfer between polyanions.     

荷移分光光度法测定醋酸氯己定

通过醋酸氯己定与红紫素的荷移反应来测定制剂中醋酸氯己定的含量,是利用分光光度法进行测定的。反应在乙醇-丙酮介质中进行,反应物的最大吸收波长为545 mn,表观摩尔吸光系数为1.54×10~4 L·mol-1·cm-1,相对标准偏差为0.89％(n=6),药物浓度在0-45 mg·L-1范围内呈线性关系;此方法简便易行,条件易于控制,灵敏度高,对样品的测定结果令人满意。