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A sensitive, simple and rapid stability-indicating HPLC method using fluorescence detection was developed for the quantitative determination of the antihistaminic drug cyproheptadine hydrochloride ...

Background and Study Aims: Effect of peginterferon and ribavirin treatment on chronic hepatitis C virus infection has been early established. However, predictors of treatment success need more elucidation. The present study is directed to estimate the importance of rapid virological response, and other host and viral factors in naïve Egyptian patients treated with 48 weeks of pegylated interferon and ribavirin. Patients and Methods: A total of 111 naïve Egyptian patients with chronic hepatitis C genotype 4 were randomly assigned to a treatment regimen consisting of either peginterferon-alpha-2a (180 μg/week) or peginterferon-alpha-2b (1.5 μg/Kg/week) plus oral ribavirin (10.6 mg/Kg/day). This treatment was given for 48 weeks with a 24-week follow-up. The endpoint was sustained virological response. Results: Overall, sustained virological response was achieved by 85 (70.2%) patients, while 26 (21.5%) patients relapsed. Rapid virological response occurred in 95 patients where 77 (84.6%) of them attained SVR and 14 (15.4%) of them relapsed (P\lt;0.001). Concerning host and viral factors, age, gender and pretreatment viral load, they all did not influence the outcome of therapy. On the other hand, higher liver fibrosis stage according to Metavir score (F3) significantly modified the sustained virological response compared to stage F1 with an Odds ratio 5.9 (95% confidence interval (CI): 1.1-31.0) and compared to F2 with an Odds ratio 7.2 (95% confidence interval (CI): 1.3-40.9). Conclusion: Rapid virological response is an independent factor that influences the sustained virological response. Besides, low pretreatment fibrosis stage is a predictor of sustained virological response.

Two simple and rapid spectrophotometric methods were developed for the simultaneous determination of methocarbamol (MET) and aspirin (ASP) in their combined dosage form. The first method, zero-crossing first derivative spectrophotometry, is based on the measurement of the first derivative amplitude values at 279.2 nm and 246.6 nm for the simultaneous determination of MET and ASP, respectively. The second method, ratio first derivative spectrophotometry, is based on the measurement of the peak amplitudes of the first derivative of the ratio spectra at 284 nm for MET and at 238.2 and 246 nm for ASP determination. The calibration graphs were linear over the range of 2.0–30.0 μg mL−1 for MET and ASP by the two proposed methods. The detection limits of the first derivative method were found to be 0.2998 and 0.3227 μg mL−1 and the quantitation limits were 0.9084 and 0.9780 μg mL−1 for MET and ASP, respectively. For the ratio first derivative method, the limits of detection and quantitation were 0.2795 and 0.8470 μg mL−1 for MET, respectively, while for ASP the limits of detection and quantitation were 0.2485 and 0.7530 μg mL−1 at 238.2 nm and 0.4173 and 1.2647 μg mL−1 at 246 nm. The proposed methods were applied successfully in the assay of the studied drugs in their combined tablets. The results compared favorably to those obtained by the reference methods.

A highly sensitive, simple and rapid spectrofluorimetric method was developed for the determination of lacidipine (LCP) in tablets. The proposed method is based on the investigation of the fluorescence spectral behavior of LCP in both sodium dodecyl sulphate (SDS) and the tween-80 micellar system. In aqueous solutions of acetate buffer (pH 4.5), the fluorescence intensities of LCP were greatly enhanced (ca. 2.4 and 4.3 folds) in the presence of either SDS or tween-80, respectively. The fluorescence intensity was measured at 444 nm after excitation at 277 nm using either SDS or tween-80 as a surfactant. The fluorescence–concentration plots were rectilinear over the ranges of 50.0–500.0 ng/ml and 5.0–200.0 ng/ml with lower detection limits of 5.11 and 2.06 ng/ml and lower quantification limits of 17 and 6.87 ng/ml using SDS and tween-80, respectively. The method was successfully applied to the analysis of LCP in commercial tablets and the results were in good agreement with those obtained with the comparison method. Furthermore, content uniformity testing of pharmaceutical tablets was also conducted. Copyright © 2014 John Wiley & Sons, Ltd.

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.

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.

A new simple, rapid, and sensitive reversed-phase liquid chromatographic method was developed and validated for the simultaneous determination of methocarbamol (MET) and ibuprofen (IBU) in their combined dosage form. The separation of these compounds was achieved within 7.0 min on a CLC Shim-pack C8 column (250 × 4.6 mm, 5-µm particle size) using isocratic mobile phase containing a mixture of methanol and 0.05 M dihydrogen phosphate buffer (75:25, v/v) at pH 6.5. The analysis was performed at a flow rate of 1.0 mL/min with fluorescence-detection at 295 nm after excitation at 224 nm. The selectivity, linearity of calibration, accuracy, intra- and inter-day precision and recovery were examined as parts of the method validation. The concentration–response relationship was linear over a concentration range of 0.05–0.50 µg/mL for MET and 0.03–0.50 µg/mL for IBU with a limit of detection 3.8 ng/mL and 1.6 ng/mL for MET and IBU, respectively. The proposed method was applied for the simultaneous determination of ...

A new simple, rapid and sensitive reversed-phase liquid chromatographic method was developed and validated for the simultaneous determination of methocarbamol (MET) and aspirin (ASP) in their combined dosage form. The separation of these compounds was achieved within 6.0 min on a CLC Shim-pack C8 column (250 × 4.6 mm, 5 µm particle size) using isocratic mobile phase consisting of acetonitrile and 0.02 M dihydrogenphosphate buffer (30:70, v/v) at pH = 5.0. The analysis was performed at a flow rate of 1.0 mL/min with fluorescence detection at 277/313 nm for MET and 298/410 nm for ASP using real-time programming. The selectivity, linearity of calibration, accuracy, inter- and intra-day precision and recovery were examined as parts of the method validation. The concentration-response relationship was linear over concentration ranges of 0.02-0.20 and 0.02-0.40 µg/mL for MET and ASP, respectively, with a limit of detection of 6 and 32 ng/mL for MET and ASP, respectively. The proposed method was successfully applied for the analysis of both MET and ASP in prepared tablets with average recoveries of 99.88 ± 0.65% for MET and 100.44 ± 0.78% for ASP. The results were favourably compared to those obtained by a reference method.

The study represents the first report on the development of spectrophotometric methods for determination of ethamsylate (EST) in the presence of hydroquinone as an impurity and/or acidic degradation product. The proposed methods are based on the reaction of EST through it,s secondary amino group either with 1,2-naphthoquinone-4-sulphonate sodium (NQS) at pH 10.7 or 2,4-dinitrofluorobenzene (DNFB) at pH 9.3 to form orange and yellow colored reaction products peaking at 478 and 387 nm for methods (I) and (II), respectively. The different experimental parameters affecting the development and stability of the reaction products in methods (I) and (II) were carefully studied and optimized. The absorbance-concentration plots were rectilinear over the concentration ranges of 2-30 and 2-14 µg mL−1 for methods (I) and (II), respectively. The lower detection limits were 0.13 and 0.19 µg mL−1 and the lower quantitation limits were 0.44 and 0.63 µg mL−1 for methods (I) and (II), respectively. Both methods were successfully applied to commercial ampoules and tablets.

Objective The aim of this study was to evaluate the reliability of a non-invasive method (saliva) for determination of testosterone level in diagnosing cases of Polycystic Ovarian Syndrome (PCOS), and comparing it with serum free testosterone. Study design Prospective clinical controlled trial. Participants and interventions Fifty women with PCOS and 20 normal women as control group were selected for the study. They all aged between 23 and 35year. For all patients serum follicle stimulating hormone (FSH) and luteinizing hormone (LH) were assessed by chemiluminescent assay. Serum free testosterone (FT) was assayed by radioimmunoassay (RIA) and salivary testosterone (ST) by ELISA technique. BMI was calculated for all participants and transvaginal sonography to determine ovarian morphology and ovarian volume. Results The present study showed a significant positive correlation between salivary testosterone, as measured by ELISA, and serum free testosterone measured by RIA (p=0.001 and r=0.52). Using the receiver operator curve, salivary testosterone was found to be more sensitive than serum (FT) (84% vs. 66%) in diagnosing PCOS patients. Conclusion Determination of salivary testosterone is a reliable method to detect changes in the concentration of available biologically active testosterone in the serum. Salivary testosterone provides a sensitive, simple, reliable, non-invasive and uncomplicated diagnostic approach for PCOS.

A sensitive and rapid spectrophotometric procedure has been investigated for the determination of fenoterol either per se or in pharmaceutical preparations. The proposed procedure is based on the reaction between the drug and 4-chloro-7-nitrobenzo-2-oxa-1,3-diazole (NBD-Cl) at pH 7.2, using borate buffer, to produce a yellow adduct. The latter has maximum absorbance at 400 nm and obeys Beer's law within the concentration range 5-30 microg/ml. Regression analysis of the calibration data showed a good correlation coefficient (r=0.9996) with minimum detection limit of 0.24 microg/ml (6.2 x 10(-8) M). The proposed procedure has been successfully applied to the determination of this drug in its tablets and in syrup, the mean percent recoveries were 97.45+/-0.59 and 98.7+/-0.64%, respectively. The results obtained are in good agreement with those given using a reference method. The pharmaceutical additives other than active ingredient did not interfere. A proposal of the reaction pathway has been postulated.

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.

A new simple, rapid and sensitive reversed-phase liquid chromatographic method was developed and validated for the simultaneous determination of methocarbamol (MET) and aspirin (ASP) in their combined dosage form. The separation of these compounds was achieved within 6.0 min on a CLC Shim-pack C8 column (250 × 4.6 mm, 5 µm particle size) using isocratic mobile phase consisting of acetonitrile and 0.02 M dihydrogenphosphate buffer (30:70, v/v) at pH = 5.0. The analysis was performed at a flow rate of 1.0 mL/min with fluorescence detection at 277/313 nm for MET and 298/410 nm for ASP using real-time programming. The selectivity, linearity of calibration, accuracy, inter- and intra-day precision and recovery were examined as parts of the method validation. The concentration-response relationship was linear over concentration ranges of 0.02-0.20 and 0.02-0.40 µg/mL for MET and ASP, respectively, with a limit of detection of 6 and 32 ng/mL for MET and ASP, respectively. The proposed method was successfully applied for the analysis of both MET and ASP in prepared tablets with average recoveries of 99.88 ± 0.65% for MET and 100.44 ± 0.78% for ASP. The results were favourably compared to those obtained by a reference method.

A new simple, rapid and sensitive reversed-phase liquid chromatographic method was developed and validated for the simultaneous determination of ascorbic acid (ASC) and salicylamide (SAL) in their combined dosage form. The analysis was carried out on CLC Shim-pack C8 column (250 x 4.6 mm, 5 μm particle size) using a mobile phase consisting of methanol: 0.03 M phosphate buffer mixture (55: 45, v/v) of pH 4.0. The mobile phase was pumped at a flow rate of 1 mL/min with ultraviolet detection at 255 nm. The selectivity, linearity of calibration, accuracy, intra and inter day precision and recovery were examined as parts of the method validation. The concentration– response relationship was linear over a concentration range of 0.50-10.00 and 5.00-50.00 μg/mL for ASC and SAL, respectively with limits of detection of 0.048 and 0.676 μg/mL. The proposed method was applied for the simultaneous determination of the two studied drugs in their combined tablets with average recoveries of 100.04 ± 0.75% and 100.11 ± 1.04% for ASC and SAL, respectively. The results were favorably compared to those obtained by the comparison methods.

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.

A rapid, simple and highly sensitive first derivative synchronous fluorometric method has been developed for the simultaneous analysis of binary mixture of sulpiride (SUL) and mebeverine hydrochloride (MEB). The method is based upon measurement of the synchronous fluorescence intensity of these drugs at ∆λ = 100 nm in water. The different experimental parameters affecting the fluorescence of the two drugs were carefully studied and optimized. The fluorescence-concentration plots were rectilinear over the range of 0.05–1 µg/mL and 0.2–3.2 µg/mL for SUL and MEB respectively with lower detection limits (LOD) of 0.006 and 0.01 µg/mL and quantification limits (LOQ) of 0.0.02 and 0.05 µg/mL for SUL and MEB, respectively. The proposed method was successfully applied for the determination of the two compounds in synthetic mixtures and in commercial tablets. The high sensitivity attained by the proposed method allowed the determination of both of SUL and MEB metabolite (veratic acid) in real human plasma samples applying second derivative synchronous fluorometric technique. The mean% recoveries (n = 3) for both MEB metabolite (veratic acid) and SUL were 99.82 ± 2.53 and 98.84 ± 6.20 for spiked human plasma respectively, while for real human plasma, the mean% recoveries (n = 3) were 91.49 ± 4.25 and 91.36 ± 8.46 respectively.

A simple, accurate, and reliable titrimetric method is described for the determination of six antimony(III) compounds, namely: antimony(III) oxide, antimony(III) chloride, tartar emetic, bilharcid, astiban, and anthiomaline. The suggested method involved the use of N,N -dibromodiethylbarbituric acid (5 × 10 −3 M ) solution as titrant. The detection of the end point could be accomplished either visually, using dye-stuffs as indicators, or potentiometrically using a platinum/calomel electrode system. Alternatively, spectrophotometric titration was also performed. The molar reactivity was assessed and a proposed reaction pathway is presented. The suggested method was applied to the determination of the studied compounds in dosage forms, and the results compared favorably with the official or published methods.

Flumequine was found to be reduced at the dropping mercury electrode in Britton-Robinson buffer containing methanol as a solubilizer, over the pH range 5–10. A well-defined cathodic wave was produced over this entire range. The wave was characterized as being diffusion-controlled, although adsorption phenomena played a limited role in the reduction process. The proposed method was applied to the determination of Flumequine in tablets, and the results were satisfactorily accurate and precise.

A highly sensitive and simple spectrofluorimetric method has been developed for the determination of almotriptan malate (ALM) and zolmitriptan (ZOL) in their pharmaceutical preparations. The proposed method is based on the investigation of the fluorescence spectral behavior of the two drugs in aqueous acidic systems. The fluorescence intensity was measured at 360 and 350 nm after excitation at 270 nm for ALM and ZOL, respectively. The fluorescence–concentration plots were rectilinear over the range 0.1–1.2 μg mL−1 and 5–40 ng mL−1, with lower detection limits of 0.03 μg mL−1 and 0.70 ng mL−1 for ALM and ZOL, respectively. The proposed method was successfully applied for the assay of commercial tablets as well as for content uniformity testing. The application of the proposed method was extended to the assay of ZOL in biological fluids. The results were statistically compared to those obtained by comparison methods and were found to be in good agreement.

Cirrhosis (Cir) is often associated with chronic renal failure (CRF) in Egyptian patients on regular hemodialysis (RHD). This is largely attributed to hepatosplenic schistosomiasis and concomitant Hepatitis C viral infection. As the liver has a major role in vitamin D3 activation, we designed this study to envisage the impact of Cir on renal osteodystrophy (ROD). It included 130 consecutive age- and gender-matched subjects in 4 categories. Group I: 39 patients (34 male and 5 female; mean age 48.8 years) with Cir normal renal function; group II: 37 patients (30 male and 7 female; mean age 49.0 years) with CRF and normal liver function, on RHD for a mean duration of 6 ± 3.9 years; group III: 41 patients (30 male and 11 female; mean age 50.7 years) with CRF and concomitant Cir, stable on RHD for a mean duration of 7.0 ± 4.0 years; and group IV: 16 normal volunteers (13 male and 3 female; mean age 46.3 years). The prevalence of diabetes as well as previous infection with schistosomiasis was similar in all patient groups and that of HCV infection was alike in groups I and III. In all subjects, conventional parameters of liver and renal function were tested; in addition to measurement of serum total protein, albumin, calcium, phosphate, total and bone-specific alkaline phosphatase (B-ALP), parathormone (PTH), 5-hydroxycholecalciferol (5HD), 1,25-dihydroxycholecalciferol (1,25HD), Cross Laps (CXL) as a marker of bone resorption, and aminoterminal propeptide of type I procollagen (PINP) as a measure of bone formation. Bone mineral density (BMD) was measured by either Dual Energy X-ray Absorptiometry (DEXA) or Computerized Tomography (CT). Group II patients displayed the typical CRF profile comprising hypocalcemia, hyperphosphatemia, increased total and bone-specific alkaline phosphatases, high PTH and 25HD, low 1,25HD, increased PINP as well as CXL, and generally decreased BMD. Cir (Group III) significantly (p value at least

N,N-Dibromodiethylbarbituric acid has been evaluated as an oxidimetric titrant in an aqueous acidic medium. It was found to oxidize reducing species easily, with the transfer of four electrons, and to be capable of brominating certain moieties embedded in pure pharmacodynamic molecules in situ. The reagent was investigated for the determination of a number of hydrazine derivatives of pharmaceutical interest. The detection of the end-point could be accomplished by using any one of three techniques: visually, using dyestuffs as indicators, spectrophotometrically or potentiometrically. The proposed method was applied to the determination of the compounds studied in dosage forms. The results obtained compared favourably with those given by the official methods.

Two spectrophotometric methods are proposed for the simultaneous spectrophotometric determination of phenaaopyridine and nitrofurantoin in tablets. No preliminary separation step is required. The first method involves the use of the modified Vierardt equation as developed by Glenn. The second method is based on the spectral changes induced bg reduction using Zn/HCl; the absorption spectrum of nitrofurantoin completely disappears, Phenazopyridine on the other hand develops a new absorption spectra at 320 nm, the absorbance ratio of the peak at 380 nm to that at 320 nm could be adopted to develop a spectrophotometric method for the determination of both compounds in admixture. The suggested methods were applied to the determination of the two compounds in tablets, and the results obtained were accurate and precise.

Two Spectrophotometric methods were developed for the estimation of pyrithioxin dihydrochloride in its formulations. The first method involves the use of 2,6-dichloroquinone-4-chlorimide (DQC) whereby a bluish-green colour is produced with Λmax at 650. In the second method, pyrithioxin is reduced using Zn[ddot]/HCL, allowed to react with p-phenylenediamine, followed by ferric ammonium sulphate whereby a bluish-violet colour is produced having a Λmax at 600 nm. The stoichiometric balance of both reactions was assessed and proposals of the reacition pathways were presented. The suggested methods were applied successfully for the determination of pyrithioxin in tablets and syrups.

While many pathobiochemical consequences of lipid peroxidation like hepatotoxicity, ageing and artherosclerosis have been described in the literature, no non-destructive biochemical function of lipid peroxidation has been demonstrated unequivocally. A negative association between the extent of lipid peroxidation in tumour cells and their proliferative behaviour has been postulated (Bartoli and Galeotti 1979). Experimental evidence is available in the literature for the following factors, which may contribute to this negative association: (a) Decreased content of polyunsaturated fatty acids, (b) Shift of the balance between pro-oxidant (e. g. iron) and antioxidant (e. g. glutathione) substances to the antioxidant side. (c) decreased activity of peroxidative enzymes (e. g. NADPH-cytochrome c reductase), (d) reduced access of oxygen as a consequence of increased tumour membrane rigidity.

A spectrophotometric method for the determination of three nitro derivatives, namely, oxamniquine, nitrazepam and chloramphenicol, is described. The proposed method involves reduction of the analyte with Zn-HCl followed by diazotisation and coupling of the resulting diazonium salt with ethyl acetoacetate in alkaline medium. The stoicheiometry of the reaction was assessed and a possible reaction pathway is presented. The nominal recovery of the drugs from pharmaceutical preparations ranges from 98.78 ± 0.51 to 100.96 ± 0.81%. The method is simple, sensitive and applicable to unit dose analysis.

The analytical utility of ethyl acetoacetate for the spectrophotometric determination of benzothiadiazine diuretics has been studied. The procedure developed is based on coupling of the diazotized drugs with the reagent, which possesses an active methylene group. The stoichiometry of the reaction is presented. The nominal recovery of the drugs from pharmaceutical preparations ranges from 97.6 ± 0.7 to 102.3 ± 0.3%. The suggested method is simple, sensitive and applicable to unit dose analysis.