Dalia M. Nagy

Development of spectrofluorimetric method for determination of certain aminoglycoside drugs in dosage forms and human plasma through condensation with ninhydrin and phenyl acetaldehyde

A simple and sensitive spectrofluorimetric method has been developed and validated for determination of amikacin sulfate, neomycin sulfate and tobramycin in pure forms, pharmaceutical formulations and human plasma. The method was based on condensation reaction of cited drugs with ninhydrin and phenylacetaldehyde in buffered medium (pH 6) resulting in formation of fluorescent products which exhibit excitation and emission maxima at 395 and 470nm, respectively. The different experimental parameters affecting the development and stability of the reaction products were carefully studied and optimized. The calibration plots were constructed with good correlation coefficients (0.9993 for tobramycin and 0.9996 for both neomycin and amikacin). The proposed method was successfully applied for the analysis of cited drugs in dosage forms with high accuracy (98.33-101.7)±(0.80-1.26)%. The results show an excellent agreement with the reference method, indicating no significant difference in accuracy and precision. Due to its high sensitivity, the proposed method was applied successfully for determination of amikacin in real human plasma.

Spectrofluorimetric determination of certain biologically active phenothiazines in commercial dosage forms and human plasma.

A validated simple and sensitive spectrofluorimetric method was developed for the determination of chlorpromazine hydrochloride, promethazine hydrochloride, trifluperazine hydrochloride, thioridazine hydrochloride, perazine maleate and oxomemazine. The method was based on condensation of malonic acid/acetic anhydride (MAA) under the catalytic effect of the tertiary amine moiety of the studied phenothiazines to provide a deep yellow to brown colour with green fluorescence. Relative fluorescence intensity of the products was measured at λ exc 398 nm and λ em 432 nm. Different variables affecting the reaction were studied and optimized. The method was successfully applied for the determination of the studied drugs in commercial dosage forms. The lower detection limits allowed the application of this method for the determination of the compounds in plasma as an example of a biological fluid. In addition, the method was considered specific for the determination of tertiary amines in the presence of primary and secondary amines; as a result, it was deemed suitable for the determination of the cited drugs in the presence of their degradation products resulting from N-dealkylation or oxidation of the corresponding sulphoxides or sulphones.

Analysis of quetiapine in human plasma using fluorescence spectroscopy

A simple and sensitive spectrofluorimetric method has been development for the assurance of quetiapine fumarate (QTF). The proposed method was utilized for measuring the fluorescence intensity of the yellow fluorescent product at 510nm (λex 470nm). The fluorescent product has resulted from the nucleophilic substitution reaction of QTF with 4-chloro-7-nitrobenzofurazane (NBD-Cl) in Mcllvaine buffer (pH7.0). The diverse variables influencing the development of the reaction product were deliberately changed and optimized. The linear concentration range of the proposed method was of 0.2-2.0μgml-1.The limits of detection and quantitation were 0.05 and 0.17μgml-1, respectively. The proposed method was applied for the assurance of QTF in its tablets without interference from basic excipients. In addition, the proposed method was used for in vitro analysis of the QTF in spiked human plasma, the percent mean recovery was (n=3) 98.82±1.484%.

An experimental ninhydrin design approach for the sensitive spectrofluorimetric assay of milnacipran in human urine and plasma

Women are the most ones who susceptible to a common syndrome called fibromyalgia syndrome, up to 90% of all people with fibromyalgia are women. It affects mainly muscles and soft tissue and cause for them muscle pain, sleep problems and painful tender points. Milnacipran is acting as a serotonin-norepinephrine reuptake inhibitor (SNRI) therefore, it is recommended for the treatment of this syndrome. The widespread use of this compound in our market requires the development and validation of a simple, sensitive, cheap, fast and reproducible spectrofluorimetric method for the assay of milnacipran hydrochloride in its pure state, pharmaceutical tablets and spiked human urine and plasma. In the current work ninhydrin and phenylacetaldehyde in Teorell and Stenhagen buffer (pH 7) reacts with the amino moiety of milnacipran through a sensitive condensation reaction resulting in formation of a fluorescent product, which exhibits its fluorescence emission intensity at 465 nm after excitation at 390 nm. It is observed that, in the concentration range 0.5 to 3.0 μgmL-1, the constructed calibration curve was linear with a good correlation coefficient (0.9998). The condensation reaction was successfully applied for the assay of the studied drug in Avermilan® tablets, spiked human urine and plasma without interference from the components of the sample matrix with average percentage recoveries of 101.73 ± 0.56 and 100.55 ± 0.64 for urine and plasma, respectively.

Application of a xanthene dye, eosin Y, as spectroscopic probe in chemical and pharmaceutical analysis; a review

Abstract Eosin Y (EY) is an acidic xanthene dye which is mainly used in food stuff and biological staining. Various analytical methods have been reported for the utility of this dye in the quantitative determination of several pharmaceutical compounds, heavy metals in addition to some surfactants and proteins. Most of the applied methods were based on the formation of association complexes between eosin Y and the target analytes in buffered aqueous solutions. The present article represents a comprehensive review for the use of eosin Y as a probe in analytical chemistry.

Facile complexation reactions for the selective spectrofluorimetric determination of albendazole in oral dosage forms and spiked human plasma

Two simple, sensitive, and rapid spectrofluorimetric methods were developed and validated for the determination of albendazole. The first method (method I) was based on the quenching effect of albendazole on the native fluorescence of erythrosine B. The fluorescence intensity was measured at 554 nm after extraction at 527 nm. In the second method (method II) the drug was reacted with lanthanum(III) ions to form a metal complex, which was measured at 340 nm after excitation at 295 nm. The suitable pH was 3.4 (Teorell–Stenhagen buffer) and pH 5.5 (phosphate buffer solution), for method I and II, respectively. The influence of experimental factors on the fluorescence intensity of the reaction products was investigated and optimized. The linear concentration ranges were 0.2–3.5 and 0.06–0.90 μg mL−1, with detection limits of 0.049 and 0.019 μg mL−1 for method I and II, respectively. ICH guidelines were followed for validation of the developed procedures, and the results were acceptable. The Gibbs free energy change of the reactions was −24.6 and −27.5 kJ mol−1 for method I and II, respectively. These negative values indicated the high feasibility of these reactions at ambient temperature. The proposed procedures were applied successfully for the determination of albendazole in commercial dosage forms and spiked human plasma. The results showed high precision, accuracy and recovery of the reported methods without any significant interference from pharmaceutical excipients or plasma components.

Utility of the chromogenic and fluorogenic properties of benzofurazan for the assay of milnacipran in human urine and plasma

Our article presents the development and validation of two simple, very sensitive, and low-cost spectroscopic methods for the assay of milnacipran hydrochloride in bulk form, pharmaceutical tablets and spiked human urine and plasma. Spectroscopic methods (spectrophotometric and spectrofluorimetric techniques) were dependent on the chromogenic and fluorogenic properties of the 4-chloro-7 nitrobenzofurazan (NBD-Cl) reagent. The reaction product, resulting from the interaction between NBD-Cl and milnacipran in the presence of borate buffer pH 8.5, was measured spectrophotometrically at 465 nm and spectrofluorimetrically at 510 nm after excitation at 465 nm. The absorbance–concentration plot was rectilinear over the range of 1.5–12 μg mL−1 with a limit of quantitation 1.09 μg mL−1, while the fluorescence–concentration plot was rectilinear over the range of 0.03–0.5 μg mL−1 with a limit of quantitation 0.02 μg mL−1. Influential parameters affecting the development and stability of the reaction product were studied and optimized. Assurance of the cited drug in its tablets by our proposed methods was successfully completed without obstruction from the presence of the basic excipients with average percentage recoveries of 99.27 ± 1.18 and 99.44 ± 0.69 for the spectrophotometric and spectrofluorimetric methods, respectively. The spectrofluorimetric method was additionally adopted as a preliminary in vitro study for the assay of the cited drug in spiked human urine and plasma with average percentage recoveries of 101.52 ± 1.01 and 100.38 ± 1.57 for spiked urine and plasma, respectively.