Novel validated spectrofluorimetric methods for the determination of taurine in energy drinks and human urine.

Two sensitive, selective, economic and validated spectrofluorimetric methods were developed for the determination of taurine in energy drinks and spiked human urine. Method Ι is based on fluorimetric determination of the amino acid through its reaction with Hantzsch reagent to form a highly fluorescent product measured at 490 nm after excitation at 419 nm. Method ΙΙ is based on the reaction of taurine with tetracyanoethylene yielding a fluorescent charge transfer complex, which was measured at λex /em of (360 nm/450 nm). The proposed methods were subjected to detailed validation procedures, and were statistically compared with the reference method, where the results obtained were in good agreement. Method Ι was further applied to determine taurine in energy drinks and spiked human urine giving promising results. Moreover, the stoichiometry of the reactions was studied, and reaction mechanisms were postulated.

Micellar HPLC and derivative spectrophotometric methods for the simultaneous determination of fluconazole and tinidazole in pharmaceuticals and biological fluids.

Micellar high-performance liquid chromatography (HPLC) and first-derivative ultraviolet spectrophotometry were used to simultaneously determine fluconazole (FLZ) and tinidazole (TNZ) in combined pharmaceutical dosage forms. The derivative procedure is based on the linear relationship between the drug concentration and the first derivative amplitudes at 220 and 288 nm for FLZ and TNZ, respectively. The calibration graphs were linear in the range of 1.5-9.0 µg/mL for FLZ and 10.0-60.0 µg/mL for TNZ. Furthermore, an HPLC procedure with ultraviolet detection at 210 nm was developed. For the HPLC procedure, good chromatographic separation was achieved using an ODS C18 column (250 × 4.6 mm i.d.). The mobile phase containing 0.15M sodium dodecyl sulphate, 0.3% triethylamine and 12% n-propanol in 0.02M orthophosphoric acid at pH 5.5 was pumped at a flow rate of 1 mL/min. Indapamide was used as an internal standard. The method showed good linearity over the concentration ranges of 1.5-30.0 and 10.0-200.0 µg/mL, with limits of detection of 0.36 and 2.70 µg/mL and limits of quantification of 1.1 and 8.2 µg/mL for FLZ and TNZ, respectively. The suggested methods were successfully applied for the simultaneous analysis of the drugs in their laboratory prepared mixture, co-formulated tablet and single dosage forms. Moreover the second method was also extended to the determination of the drugs in biological fluids.

Micelle-enhanced spectrofluorimetric method for determination of cyproheptadine hydrochloride in tablets: application to in-vitro drug release and content uniformity test.

A highly sensitive and simple spectrofluorimetric method was developed for the determination of cyproheptadine hydrochloride (CYP) in its pharmaceutical formulations. The proposed method is based on the investigation of the fluorescence spectral behaviour of CYP in a sodium dodecyl sulphate (SDS) micellar system. In aqueous solution, the fluorescence intensity of CYP was greatly enhanced (150 %) in the presence of SDS. The fluorescence intensity was measured at 410 nm after excitation at 280 nm. The fluorescence-concentration plot was rectilinear over the range 0.2-2.0 µg/mL, with lower detection limit of 0.06 µg/mL. The proposed method was successfully applied to the assay of commercial tablets as well as content uniformity testing. The application of the proposed method was extended to test the in-vitro drug release of CYP tablets, according to USP guidelines. The results were statistically compared with those obtained by official USP method and were found to be in good agreement.

Spectrofluorimetric determination of terbinafine hydrochloride and linezolid in their dosage forms and human plasma.

A highly sensitive, simple and rapid spectrofluorimetric method was developed for the determination of Terbinafine HCl (TRH) and linezolid (LNZ) in their pharmaceutical formulations. The proposed method is based on measuring the native fluorescence of the studied drugs in water at 336 nm after excitation at 275 nm for TRH and 375 nm after excitation at 254 nm for LNZ. The fluorescence-concentration plots were rectilinear over the range of 0.02-0.15 µg/mL for TRH and 0.5-5.0 µg/mL for LNZ. With lower detection limits of 3.0 and 110.0 ng/mL and a lower quantification limit of 9.0 and 320.0 ng/mL for TRH and LNZ, respectively. The method was successfully applied to the analysis of TRH in its commercial tablets, cream, gel and spray formulations and the results were in good agreement with those obtained with the official method. In addition the method was also applied to the analysis of LNZ in its capsule and I.V solution and the results were in good agreement with those obtained with the comparison method. The effect of sensitizers was studied. The method was extended to the determination of the studied drugs in spiked human plasma and the results were satisfactory.

Clinical, parasitological and social studies on Wuchereria bancrofti in Egypt.

This study was conducted on patients attending Al-Hussein University Hospital and Mansura University Hospitals. Sheets were filled out on each patient (age, residence, occupation, family similar condition, travelling, disease duration, symptoms suggesting acute dermatolymphangitis attacks, frequency and duration. They were 25 lymphoedema patients and 8 controls (17 males & 16 females) and subjected to clinical and parasitological examinations. According to residence, five patients were from Giza Govemorate (18.18%), four from Dakahlia G. (12.12%), four from Gharbia G. (12.12%), five from Menoufia G. (15.15%), four from Sharkia G. (12.12%), two cases from Kafr Elsheikh G. (6.06%) and one patient from Assiut G. (3.03%). In controls, 6 were from Al-Hussein Cairo G. (15.15%), and two cases (6.06) from Al-Abbassia. They were 48% farmers (10 male & 2 female); 4% grocers (1 male); 8% carpenters (2 male); and 40% house wife (10 female). According to lymphedema site: 3 cases (12%) were bilateral lower limbs lymphedema (2 female & 1 male), 13 cases (52%) had right lower limb lymphedema (6 female & 7 male), and 9 cases (36%) had left lower limb lymphedema (4 female & 5 male). They were 18 (72%) with below knee extension of lymphedema (10 male & 8 female) and 7 (28%) above knee extension of lymphedema (3 male & 4 female). Grade of lymphedema was one case (male) with grade II lymphedema (4%), 13 cases (52%) with grade III (7 male & 6 female) and 11 cases (44%) with grade IV (5 male & 6 female). Duration of lymphedema was one case with grade II lymphedema in a period of 3 years, 13 cases with grade III lymphedema and the durations of lymphedema for these cases were (one case with 5 years duration, 3 cases were > 6-9 years,6 cases were > 9-12 years and 3 cases were > 12 years) and 11 cases with grade IV lymphedema and duration of lymphedema for these cases were (one case with 6 years duration, 2 cases were > 6-9 years,3 cases were > 9-12 years and 5 cases were > 12 years).

Kinetic determination of ribavirin in drug formulations.

Two simple and sensitive kinetic methods were developed for the determination of ribavirin in bulk and in its pharmaceutical preparations using alkaline potassium permanganate as an oxidizing agent. The methods are based upon a kinetic investigation of the oxidation reaction of the drug at room temperature for fixed times of 20 and 30 minutes. In the first method, the absorbance of the colored manganate ion was measured at 610 nm, while in second method the reduction in the absorbance of permanganate was measured at 525 nm. The absorbance concentration plots were linear over the range of 3-15 µg/ml with detection limits of 0.028 µg/ml in the first method and 0.229 µg/ml for the second method. The proposed methods were applied successfully for the determination of the drug in its pharmaceutical formulations, the percentage recoveries were 100.15 ± 1.34, 100.06 ± 0.86 in the first method, and 99.60 ± 0.54, 100.43 ± 0.82 in the second method. The results obtained were compared statistically with those obtained by the official method and showed no significant differences regarding accuracy and precision.

Comparative study on the para-metabolic oxidation of phenytoin and decadeuteriophenytoin.

The in-vivo metabolic conversion of equal mixture of phenytoin and decadeuteriophenytoin to the para-hydroxy metabolite in rat was investigated in order to verify a possible role of an insertion or abstraction mechanisms in the hydroxylation process. Determination of kH/k2H values of urine samples at 2 h intervals for 24 h indicated that there was no isotope effect during in-vivo para-hydroxylation of phenytoin. This gives evidence of the arene oxide intermediacy possibly being the sole pathway for para-hydroxylation of phenytoin.

A study on beta-adrenergic receptors in children with asthmatic bronchitis.

The function of beta-adrenergic receptors was assessed in 50 children with asthmatic bronchitis and 45 healthy controls by the hyperglycemic, eosinopenic and platelet aggregation responses to epinephrine. The results showed evidence of beta-adrenergic blockade in children with asthmatic bronchitis. It is suggested that this blockade may reflect a functional and/or a structural immaturity of the beta receptors in these children.

Histopathological and histochemical studies on the tonsils in children with rheumatic heart disease.

The tonsils were studied histologically and histochemically in 67 children with rheumatic heart disease, 33 children with chronic tonsillitis and 5 normal children. The tonsils of rheumatic children showed hyperplasia and hyperactivity of lymphocytes and paucity of phagocytes. It was suggested that these peculiar findings might contribute to the pathogenesis of rheumatic fever.