Laila El-Sayed Abdel Fattah

Fluorimetric determination of some antibiotics in raw material and dosage forms through ternary complex formation with terbium (Tb3

A highly sensitive and specific fluorimetric method was developed for the determination of cefazolin sodium I, cefoperazone sodium II, ceftriaxone sodium III, and cefixime IV. The proposed method involves the formation of ternary complex with Tb(3+) in the presence of Tris buffer. The quenching of the terbium fluorescence due to the complex formation was quantitative for the four studied drugs. The effect of pH, concentration of Tris buffer and terbium were studied. The formation of the complex was highly dependent on the pH. The optimum pH was found to be pH 8 for cefazolin sodium I, ceftriaxone sodium III, cefixime IV and pH 10 for cefoperazone sodium II. The optimum concentration for Tb(3+) was found 1 ml of 10(-4) M solution and for Tris buffer 1 ml of the prepared solution. Under the described conditions, the proposed method was applicable over the concentration range 8.79 x 10(-6)-7.91 x 10(-5), 9.7 x 10(-6)-4.49 x 10(-)5, 6.10 x 10(-6)-2.50 x 10(-5), and 4.92 x 10(-6)-2.95 x 10(-5) mol with mean percentage accuracy of 99.79+/-0.24, 98.97+/-1.25, 100.05+/-0.79, and 100.15+/-0.54 for I, II, III, and IV, respectively. The proposed method was applied successfully for the determination of studied drugs in bulk powder and in pharmaceutical formulations. The results obtained by applying the described method were statistically analyzed and compared with those obtained by applying the official method. The proposed method was used as stability indicating method for the determination of the studied drugs in the presence of their degradation products.

DIFFERENT SPECTROPHOTOMETRIC METHODS FOR THE DETERMINATION OF CIMETIDINE, RANITIDINE HYDROCHLORIDE, AND FAMOTIDINE

ABSTRACT In this work three different spectrophotometric methods were established for the determination of cimetidine (I), ranitidine hydrochloride (II) and famotidine (III) The first one is a colorimetric method, it was applied for the determination of the three drugs by using sodium nitroprusside as a color reagent to produce a red colored complexes. In this method, the zero order spectrum 0D was used for the determination of drug (III) at λ=500 nm while the first derivative spectra 1D were used for the determination of drug (I) and (II) at their corresponding wave lengths 523 and 510 nm and Δ λ=4 nm. The method can be considered as a stability indicating method for the determination of the three drugs in the presence of their induced hydrogen peroxide oxidative degradates. Beers law was obeyed in the concentration range of 25–150 µg·mL−1 for (I) and 50–500 µg·mL−1 for (II) and (III) with mean percentage recoveries of 100.27±0.697, 99.79±0.465 and 99.15±0.687, respectively. The second method is a simple colorimetric method, it was applied for the determination of drug (III). Where, 3-Methyl-2-benzo-thiazolinone hydrazone (MBTH) was used as a color reagent. It reacts with the drug to produce a bluish violet color, having two maxima at 536 and 620 nm. The percentage recoveries were 99.73±1.048 and 99.94±0.887, respectively within the concentration range of 20–120 µg·mL−1. The third one is a spectrophotometric method via a complex formation reaction by using cobalt II. A colorless complex was developed having λ max at 319 nm with a ratio of 1:1 and a stability constant logarithm of 5.49. The percentage recovery was 99.84±0.858 within a concentration range of 10–60 µg·mL−1. The statistical comparison with the BP official methods[1] and the assay validation for the three proposed methods has been applied. The results obtained showed that they could be used for the determination of the three drugs in pure and dosage forms.

Colorimetric and fluorimetric methods for determination of panthenol in cosmetic and pharmaceutical formulation.

Two methods are suggested for determination of panthenol. The first is colorimetric method where panthenol is subjected to alkaline hydrolysis; the resulting beta-alanol is allowed to react with vanillin (Duquenois reagent) in presence of McIlvain buffer pH 7.5. The color developed is measured at 406 nm. The linearity range was found to be 50-500 microg/ml while the lower limit of detection was about 10 microg/ml. The second is a sensitive and reliable modified fluorimetric method is also suggested, whereas panthenol, after alkaline hydrolysis is treated with ninhydrin. The fluorescent product was found to have excitation lambda(max) at 385 nm and emission lambda(max) at 465 nm. The method showed high sensitivity with linearity range from 0.01 to 3 microg/ml. The lower limit of detection (LOQ) reached 0.005 microg/ml. Validation of both methods was carried out and the two methods were applied for determination of panthenol in some cosmetic and pharmaceutical formulations.

Stability-Indicating Method for the Determination of Some Cephalosporines in the Prescence of Degradation Products

Abstract A rapid and convenient spectrophotometric method is described for the quantitative determination of some of Cephalosporines Cefadroxil, I Cephradine II and Cefaclor III. The proposed method depends upon the conversion of these compounds to the corresponding piperazine-2,5 dione derivatives by heating in an alkaline sorbitol-zinc ion solution for 10—25 minutes at 90°C and subsequent treatment of these derivatives with 0.1 N sodium hydroxide to obtain highly absorbing products with λmax at 345 nm for I & II and at 334 nm for III using zero order absorption curve. Using first derivative spectrum (D1) for III the λmax is at 362 nm. The method was found to be free of the interference from polymerization and other degradation products. Its application to assess the stability of the Cephalosporines was demonstrated. Verification of Beers Law showed lincarity at concentrations of 12.5-87.5 μg ml−1, 12.5-125 μg ml−l and 6.7-66.7 μg ml−1 for I, II and III respectively with mean accuracies 100.37 ± 0.72%, ...

UV-SPECTROPHOTOMETRIC STABILITY INDICATING METHODS FOR THE QUANTITATIVE DETERMINATION OF CIMETIDINE, FAMOTIDINE, AND RANITIDINE HYDROCHLORIDE IN THE PRESENCE OF THEIR OXIDATIVE DERIVATIVES

ABSTRACT Simple, sensitive and rapid spectrophotometric techniques have been established for the determination of cimetidine (I), famotidine (II) and ranitidine hydrochloride (III) in presence of their S-oxide derivatives in both raw materials and in pharmaceutical formulations. Hydrogen peroxide was used to enhance the formation of S-oxide compounds (oxidative derivatives). The first derivative of the ratio spectra ( 1 DD) technique has been applied for the determination of (I) and (II). While, direct zero order ( 0 D), first derivative ( 1 D) and the second derivative of the ratio spectra ( 2 DD) have been carried out for the determination of drug (III). Linear calibration curves were obtained for determination of (I) and (II) by applying 1 DD at 220 and 230 nm in the concentration range of 2–20 and 4–40 µg mL−1 with the mean percentage recoveries of 99.88 ± 0.943 (n = 10) and 99.88 ± 0.824% (n = 10) for (I) and (II), respectively. While for (III) linear calibration curves were obtained by applying 0 D, 1 D and 2 DD at 313, 334 and 255 nm, respectively. The concentration range was 2–20 µg mL−1 with the corresponding mean percentage recoveries of 100.13 ± 0.464, 100.01 ± 0.428 and 99.94 ± 0.439 for (I), (II) and (III), respectively. The results obtained by the proposed methods were statistically analyzed and compared with those obtained by the official BP methods.

Validated stability-indicating TLC method for the determination of noscapine.

A sensitive, selective, precise and stability-indicating thin-layer chromatographic (TLC) method was developed and validated for the analysis of noscapine, both as a bulk drug and in its formulation. The method employed TLC aluminium plates precoated with silica gel 60F-254 as the stationary phase. The solvent system consisted of chloroform-methanol (10:0.5 v/v). Densitometric analysis of noscapine and its degradation products was carried out in the absorbance mode at 254 nm. This system was found to give compact symmetrical spots for noscapine (R(f) value 0.85 +/- 0.04). Noscapine was subjected to acid and alkali hydrolysis, oxidation and photo degradation. The drug undergoes photo degradation and also degrades under acidic and basic conditions. The prepared degradation products were identified and verified through infrared (IR) and mass spectral analyses. The degraded products were also well resolved from the pure drug with significantly different R(f) values and they were quantitatively determined. The method was validated for linearity, precision, robustness, limit of detection (LOD), limit of quantitation (LOQ), specificity and accuracy. Linearity was found to be in the 1.0-10.0 microg, 0.4-3.2 microg, 1.0-9.0 microg and 0.5-5.0 microg/band ranges for noscapine, cotarnine, meconine and opionic acid, respectively. The polynomial regression analysis for the calibration plots showed a good polynomial relationship with r(2) of 0.9998, 9989, 9996 and 0.9997 for noscapine and its three degradation products, cotarnine, meconine and opionic acid, respectively. Statistical analysis proves that the method is repeatable and specific for the estimation of noscapine. As this approach could effectively separate the drug from its degradation products it can be employed as a stability-indicating method in Quality Control laboratories.

Chromatographic Study of Azintamide in Bulk Powder and in Pharmaceutical Formulation in the Presence of Its Degradation Form

Two specific, sensitive, and precise stability-indicating chromatographic methods were developed, optimized, and validated for the determination of Azintamide (AZ) in the presence of its degradation product. The first method was TLC combined with the densitometric determination of the separated bands. Separation was achieved using silica gel 60 F254 TLC plates and chloroform-acetone-glacial acetic acid (7.5 + 2.1 + 0.4, v/v/v) as the developing system. Good correlations were obtained between the integrated peak area of the studied drug and its corresponding concentrations in the linearity range. The second method used HPLC with UV diode-array detection, in which the proposed method was applied for the quantitative determination of AZ in the presence of its acidic degradation product and the quantitative determination of the acid-induced degradation product of AZ (AZ Deg) using pentoxifylline as the internal standard. The proposed components were separated on a reversed-phase C18 analytical column using acetonitrile-water (50 + 50, v/v). The flow rate was maintained at 0.55 mL/min and the detection wavelength was 260 nm. Linear regressions were obtained in the range of 1-30 and 0.3-16 μg/mL for AZ and AZ Deg, respectively. Different parameters affecting the suggested methods were optimized for maximum separation of the cited components. The suggested methods were validated in compliance with the International Conference on Harmonization guidelines and successfully applied for the determination of AZ in its pure powder form and in its pharmaceutical formulation. Both methods were also statistically compared with the reported method with no significant difference in performance observed.

A validated direct thin-layer chromatographic separation and enantioselective determination of racemic centrally acting drugs using ion-pair and ligand-exchange chiral selectors: A thermodynamic study of complexation

A rapid, inexpensive, and stereoselective densitometric—thin-layer chromatographic (TLC) method using l-(+)-tartaric acid and l-histidine—Cu complex as chiral mobile phase additive for the enantioseparation of atracurium besylate and atropine sulfate, respectively, and quantitative determination of their chiral switching (eutomer) isomers, cisatracurium besylate and hyoscyamine sulfate, were used in this study. The effect on resolution of different chiral selector concentrations, temperatures, and pH values was investigated. The spots were detected with ultraviolet (UV) lamp followed by densitometric measurements at 280 nm and 215 nm for cisatracurium besylate and hyoscyamine sulfate, respectively. The mobile phases enabling successful resolution were acetonitrile—methanol—dichloromethane—glacial acetic acid–H2O containing 70 mg l-(+)-tartaric acid (7:1:0.5:0.7:1, by volume), pH 5 for atracurium besylate, and methanol–H2O containing 40 mmol l-histidine and 20 mmol copper(II) acetate (8.8:1.2, by volume), pH 6.5 for atropine sulfate. Thermodynamic parameters, enthalpy ΔH and entropy ΔS were investigated to study the effect of temperature on the enantioseparation using the Van’t Hoff plot.