Simultaneous determination of diosmin and hesperidin in combined pharmaceutical preparation by synchronous fluorescence spectrofluorimetric method.

A sensitive, rapid and green synchronous spectrofluorimetric method was developed to simultaneously analyze a binary mixture of diosmin (DSM) and hesperidin (HSP). The RSFI of both medications was measured in methanol at Δλ of 100 nm. The results indicated that specific experimental factors had an impact on these intensities. The optimization and thorough examination of these parameters were conducted. The plots of synchronous fluorescence intensity-concentration for DSM and HSP were found to be linear within the concentration ranges of 0.5-5.0 µg ml-1 and 0.2-3.0 µg ml-1, respectively. The detection limits for DSM and HSP were 0.107 µg ml-1 and 0.048 µg ml-1, respectively. The limits of quantification were 0.323 µg ml-1 and 0.144 µg ml-1 for DSM and HSP, respectively. The method outlined in this study was successfully used to determine the quantities of both drugs present in commercially available mixed tablets. The results obtained using this method were subsequently compared to those of a comparison method. Greenness assessment of the suggested procedure was accomplished by applying the GAPI method. Consequently, the recommended method can be used in the routine quality control analysis of the two cited drugs with minimum harmful effect on the environment as well as the individuals.

Green, Validated HPLC Method Coupled With Fluorescence Detection for the Analysis of Tafluprost in its Pure Form and Ophthalmic Formulation: Application to Aqueous Humor and Content Uniformity Testing.

A green, simple and sensitive HPLC method coupled with fluorescence detection was implemented for the quantitative determination of the anti-glaucoma drug tafluprost (TFL). Liquid chromatography was performed on HyperClone™ ODS (C18) column of dimensions; 150 × 4.6 mm i.d. and 5 µm particle size using a green eluent; ethanol:0.01 M phosphate buffer (60:40 v/v, pH 4.5) delivered at 1 mL min-1. Fluorescence detection was accomplished at 220 nm (excitation) and 292 nm (emission). Bimatoprost (BIM) was used as an internal standard (I.S.). In this method, TFL was eluted after 6.70 minutes. The method satisfied International Council for Harmonization (ICH) validation guidelines, as proved by good linearity (r = 0.9999, over the range 0.05-2 µg mL-1), accuracy (recovery average 100.13 ± 1.27%), precision, robustness and specificity. The limit of detection and limit of quantification were found to be 0.016 and 0.048 µg mL-1, respectively. The proposed method has been successfully applied for the estimation of TFL in eye drops and aqueous humor. For the first time, the approach was applied with acceptable results for the evaluation of the uniformity of TFL eye drops content. Furthermore, Green Analytical Procedure Index (GAPI) and analytical Eco-scale were used to prove that the proposed HPLC method is environmentally friendly.

Factorial design-assisted reverse phase HPLC-UV approach for the concurrent estimation of cetirizine and azelastine in aqueous humor.

A new analytical quality by design-assisted HPLC-UV approach is presented, for the first time, for the concurrent determination of cetirizine (CTZ) and azelastine (AZE) in raw materials, commercial eye drops and aqueous humor. The two drugs are co-administered as eye drops in severe ocular allergies. A 23 full factorial design was adopted for the chromatographic optimization to ensure the best analytical performance and reliability, as well as to save time, effort and solvent consumption. The parameters, including pH, acetonitrile ratio, and flow rate, were selected as independent factors. The responses analyzed were resolution and tailing of peaks. The separation was achieved through isocratic elution on C8 column with mobile phase made up of acetonitrile: 0.3% triethylamine of pH 5 (60:40 v/v) at a flow rate of 1.2 mL min-1 and detection at 216 nm. The elution time was less than 6 min. The approach was fully validated in accordance with International Council for Harmonization (ICH) guidelines. Good linearity was achieved over the concentration ranges of 1.0-30 and 0.5-10 µg mL-1 with limits of detection of 0.310 and 0.158 µg mL-1 and limits of quantification of 0.940 and 0.479 µg mL-1 for CTZ and AZE, respectively, with correlation coefficients of 0.9998. The intra- and inter-day precisions were lower than 2%. The good sensitivity of the approach permits the analysis of CTZ and AZE in spiked aqueous humor with mean percentage recoveries of 100.93 ± 1.42 and 100.11 ± 1.55, respectively. The statistical comparison between results of the developed method and the comparison method revealed no differences, indicating the accuracy of the method.

Fractional microneedle radiofrequency versus fractional carbon dioxide laser in the treatment of postburn hypertrophic scars.

BACKGROUND AND OBJECTIVE: New and improved treatment modalities, including lasers and energy-based devices, are promising treatment options for hypertrophic scars. This study aimed to assess the efficacy and safety of fractional microneedle radiofrequency (FMR) compared with fractional carbon dioxide (CO2 ) laser in the treatment of postburn hypertrophic scars. PATIENTS AND METHODS: Twenty patients with hypertrophic scars were enrolled in the study. Two areas in each patient were randomly assigned to fractional CO2 laser or FMR. Four sessions, 6-8 weeks apart were performed. The Patient and Observer Scar Assessment Scale (POSAS) was used for clinical evaluation, H & E and orcein-stained samples were examined for histopathological assessment, and tissue transforming growth factor beta 1 (TGFß1 ) levels were measured for biochemical evaluation. RESULTS: Both fractional CO2 and FMR-treated areas showed significant improvement in all parameters 1 month after treatment. Fractional CO2-treated areas showed a higher degree of improvement compared with FMR in OSAS (p = 0.025), elastin grading (p = 0.004), and TGFß1 levels (p = 0.000). Patients reported less downtime and showed less postinflammatory hyperpigmentation with FMR compared with fractional CO2, but this did not reach statistical significance (p = 0.327, p = 0.231; respectively). CONCLUSION: Our results demonstrate the value of FMR as an effective alternative to fractional CO2 in the treatment of hypertrophic scars, with a potentially favorable safety profile.

Two spectroscopic methods for estimation of anti-migraine medications: Sumatriptan and Zolmitriptan based on nucleophilic substitution reaction.

Sensitive and selective spectrophotometric and spectrofluorimetric methods have been developed for the estimation of two anti-migraine drugs, namely sumatriptan succinate (SUM) and zolmitriptan (ZOL). These methods depend on producing a yellow-coloured product after the reaction of the two drugs with 7-chloro-4-nitrobenz-2-oxa-1,3-diazole (NBD-Cl). The reaction products exhibited maximum absorbance at 481 nm in borate buffer of pH 9 and fluorescence emission peak at 540 nm after excitation at 470 nm for the two drugs. The linear ranges were 5-60 µg/ml for SUM and 5-50 µg/ml for ZOL in the spectrophotometric method (Method I), whereas this was 0.4-4 µg/ml for SUM and 0.5-5 µg/ml for ZOL in the spectrofluorimetric method (Method II). The method validity was assessed according to International Council for Harmonisation (ICH) guidelines. Statistical analysis of the results obtained from the proposed and comparison methods confirmed that the proposed methods were highly accurate and precise. The suggested methods could be used for the determination of the mentioned drugs in both pure form and in tablets.

Green HPLC method with time programming for the determination of the co-formulated eye drops of tafluprost and timolol in their challengeable ratio.

A new, simple and selective HPLC method was implemented for the simultaneous estimation of tafluprost (TFL) and timolol (TIM) in their new anti-glaucoma combination in the challengeable ratio of 3 and 1000 for TFL and TIM, respectively. Separation was achieved using a BDS Hypersil phenyl column and a mobile phase made up of acetonitrile: 0.015 M phosphate buffer (50:50 v/v, pH 3.5) delivered at 1 mL min-1 and the separation was completed in less than 6 min. UV detection was time programmed at 220 nm for the first 4.5 min and later at 254 nm. Mebeverine (MEB) was used as an internal standard (I.S.). The linearity was observed in the ranges of 0.6-45 and 50-2000 µg mL-1 with limits of detection (LOD) of 0.18, 16.48 µg mL-1 and limits of quantification (LOQ) of 0.55, 49.94 µg mL-1 for TFL and TIM, respectively. The method satisfied International Council for Harmonization (ICH) validation guidelines. The study was extended to the estimation of the studied drugs in their co-formulated eye drops as well as in their single dosage forms with acceptable percentage recoveries. Moreover, Green Analytical Procedure Index (GAPI) and analytical Eco-scale were investigated to confirm the greenness of the proposed HPLC method.

Spectrofluorimetric investigation for determination of sumatriptan succinate: application to tablets and spiked human plasma.

A simple and highly sensitive spectrofluorimetric method for the estimation of sumatriptan succinate has been investigated. The suggested method depends on the determination of the intrinsic fluorescence properties of the drug in aqueous systems at λem 350 nm following λex at 225 nm. The linearity range was 10-100 ng/ml, with a detection limit and quantitation limit of 1.2 and 3.6 ng/ml, respectively. The suggested method was sufficiently successful for determination of sumatriptan its pharmaceutical tablets as well as in spiked human plasma. Moreover, the validation parameters were determined following International Council for Harmonisation guidelines. Statistical analysis of the obtained results from the proposed and reference methods showed no significance difference between the two methods regarding accuracy and precision.

Green highly sensitive spectrofluorimetric method for rapid determination of tafluprost in its pure form and ophthalmic formulation.

A green, simple and easy spectrofluorimetric method was studied for rapid estimation of tafluprost (TFL). The native fluorescence of TFL was measured at 292 nm after excitation at 220 nm. The results were linear in water over the concentration range 50-600 ng ml-1 with a correlation coefficient r = 0.9999 and intercept 1.1555. The limit of detection and limit of quantification were found to be 7.87 and 23.86 ng ml-1 , respectively. Neither different pH nor surfactants enhanced the fluorescence intensity. The high sensitivity of this spectrofluorimetric method makes it suitable for analysis of low concentrations of tafluprost in commercially available ophthalmic formulations. This procedure was validated according to International Council for Harmonisation Guidelines.

Simultaneous determination of cetirizine, phenyl propanolamine and nimesulide using third derivative spectrophotometry and high performance liquid chromatography in pharmaceutical preparations.

BACKGROUND: The combination between cetirizine (CET), phenylpropanolamine (PPA) and nimesulide (NMS) under trade name Nemeriv Cp tablet is prescribed for nasal congestion, cold, sneezing, and allergy. Among all published methods for the three drugs; there is no reported method concerning estimation of CTZ, PPA and NMS simultaneously and this motivates us to develop new and simple methods for their assay in pure form and tablet preparations. RESULTS: Two new methodologies were described for the simultaneous quantification of cetirizine (CTZ), PPA and NMS. Spectrophotometric procedures relies on measuring the amplitudes of the third derivative curves at 238 nm for CTZ, 218 nm for PPA and 305 nm for NMS. The calibration graphs were rectilinear over the ranges of 8-90 µg/mL for CTZ, 20-100 µg/mL for PPA and 20-200 µg/mL for NMS respectively. Regarding the HPLC method; monolithic column (100 mm × 4.6 mm i.d) was used for the separation. The used mobile phase composed of 0.1 M phosphate buffer and methanol in the ratio of 40:60, v/v at pH 7.0. The analysis was performed using UV detector at 215 nm. Calibration curves showed the linearity over concentration ranges of 5-40, 10-100 and 10-120 µg/mL for CTZ, PPA and NMS. CONCLUSION: Application of the proposed methods to the laboratory prepared tablets was carried out successfully. The results were compared with those obtained from previously published methods and they were satisfactory. Graphical abstract Graphical abstract represents the chemical structures, representative chromatogram for the HPLC separation of a PPA, b NMS and c CTZ and third derivative absorption spectra of a PPA, b NMS and c CTZ for the spectrophotometric method.

Application of silver nanoparticles to the chemiluminescence determination of cefditoren pivoxil using the luminol-ferricyanide system.

A new simple, accurate and sensitive sequential injection analysis chemiluminescence (CL) detection method for the determination of cefditoren pivoxil (CTP) has been developed. The developed method was based on the enhancement effect of silver nanoparticles on the CL signal arising from a luminol-potassium ferricyanide reaction in the presence of CTP. The optimum conditions relevant to the effect of luminol, potassium ferricyanide and silver nanoparticle concentrations were investigated. The proposed method showed linear relationships between relative CL intensity and the investigated drug concentration at the range 0.001-5000 ng/mL, (r = 0.9998, n = 12) with a detection limit of 0.5 pg/mL and quantification limit of 0.001 ng/mL. The relative standard deviation was 1.6%. The proposed method was employed for the determination of CTP in bulk drug, in its pharmaceutical dosage forms and biological fluids such as human serum and urine. The interference of some common additive compounds such as glucose, lactose, starch, talc and magnesium stearate was investigated. In addition, the interference of some related cephalosporins was tested. No interference was recorded. The obtained sequential injection analysis-CL results were statistically compared with those from a reported method and did not show any significant differences.

Spectrofluorimetric analysis of gemifloxacin mesylate in pharmaceutical formulations.

A simple, rapid and highly sensitive spectrofluorimetric method was developed for determination of gemifloxacin mesylate (GFX) in tablets. The method is based on measuring the native fluorescence of GFX in isopropanol at 400 nm after excitation at 272 nm. The fluorescence-concentration plot was rectilinear over the range of 0.01-0.50 µg/mL with a lower detection limit of 1.19 ng/mL and quantification limit of 3.6 ng/mL. The method was fully validated and successfully applied to the determination of GFX tablets with an average percentage recovery of 99.65 ± 0.532. The method was extended to the stability study of GFX. The drug was exposed to acidic, alkaline, oxidative and photolytic degradation according to International Conference on Harmonization guidelines. The rate of GFX degradation was found at its highest in acidic conditions, and in its lowest in the neutral one. However, it was stable under dry heat and photolytic degradation conditions.

Flow-injection chemiluminescence and electrogenerated chemiluminescence determination of escitalopram oxalate in tablet form.

Rapid, simple and highly sensitive flow-injection (FI) chemiluminescence (CL) and flow-injection electrogenerated chemiluminescence (ECL) methods were developed for the determination of escitalopram oxalate (ESC), a selective serotonin reuptake inhibitor used as an antidepressant drug. The CL method was based on the CL reaction of ESC with acidic cerium(IV) and tris(2,2'-bipyridyl)ruthenium(II) (Ru(bipy)(3)(2)+). Various experimental parameters affecting CL intensity were carefully studied and optimised. The method enabled the determination of 0.001-50 µg/mL of ESC in bulk form with a correlation coefficient r = 0.9999. The limit of detection (LOD) was 0.01 ng/mL (S/N = 3). The ECL method was based on the ECL reaction of Ru(bipy)(3)(2)+ with the drug in an acidic medium, permitting the determination of ESC in the range of 0.00001-70 µg/mL with r = 0.9999 and LOD of 1 x 10(-4) ng/mL. The proposed methods were applied to the determination of ESC in commercial tablets. The results were compared statistically with those obtained from a published method using t- and F-tests.

Community-acquired methicillin-resistant Staphylococcus aureus from skin and soft tissue infections (in a sample of Egyptian population): analysis of mec gene and staphylococcal cassette chromosome

BACKGROUND: Staphylococcus aureus has been recognized as an important pathogen associated with inpatients and community infections. Community-acquired methicillin-resistant S. aureus (CA-MRSA) infections commonly present as skin and soft-tissue infections (SSTIs). Treatment often includes incision and drainage with or without adjunctive antibiotics. OBJECTIVES: This study aimed to identify CA-MRSA infections both phenotypically and genotypically, to determine their spectrum of antibiotic resistance, and to establish the best scheme for molecular distinction between hospital-acquired MRSA (HA-MRSA) and CA-MRSA by staphylococcal cassette chromosome mec (SCCmec) typing and detection of Panton Valentine leukocidin (PVL). MATERIALS: 50 swabs, from skin and soft tissue of infected lesions of outpatients attending the dermatology department of the Medical School, Alexandria University, were collected. Additionally, a nasal swab was taken from every participant. METHODS: Collection of swabs from the infected skin and soft tissues, followed by laboratory testing to phenotypically and genotypically identify MRSA. Also, nasal swabs were taken from every patient to identify MRSA colonization. RESULTS: Staphylococcus aureus strains were identified in 38 (76%) of the 50 clinical isolates. 18 (47.37%) out of the 38 S. aureus strains were resistant to oxacillin and cefoxitin discs, were penicillin binding protein 2a (PBP2a) producers, and were initially diagnosed as MRSA. All of the 18 strains were definitively diagnosed as MRSA by mecA gene detection using real time PCR, while only six (33.33%) strains were PVL positive. Using the sets of primers of Zhang et al.: nine (50%) out of the 18 CA-MRSA strains were SCCmec type V, and one (5.56%) was SCCmec type IVc. Then, using the set of primers by Oliveira et al., two (25%) out of the eight untypable MRSA strains were found to be SCCmec type IV, and six (75%) remained untypable. CONCLUSIONS: CA-MRSA must be considered when treating skin and soft tissue infections, especially in developing countries. Empirical use of agents active against CA-MRSA is warranted for patients presenting with serious SSTIs.

Community-acquired methicillin-resistant Staphylococcus aureus from skin and soft tissue infections (in a sample of Egyptian population): analysis of mec gene and staphylococcal cassette chromosome.

BACKGROUND: Staphylococcus aureus has been recognized as an important pathogen associated with inpatients and community infections. Community-acquired methicillin-resistant S. aureus (CA-MRSA) infections commonly present as skin and soft-tissue infections (SSTIs). Treatment often includes incision and drainage with or without adjunctive antibiotics. OBJECTIVES: This study aimed to identify CA-MRSA infections both phenotypically and genotypically, to determine their spectrum of antibiotic resistance, and to establish the best scheme for molecular distinction between hospital-acquired MRSA (HA-MRSA) and CA-MRSA by staphylococcal cassette chromosome mec (SCCmec) typing and detection of Panton Valentine leukocidin (PVL). MATERIALS: 50 swabs, from skin and soft tissue of infected lesions of outpatients attending the dermatology department of the Medical School, Alexandria University, were collected. Additionally, a nasal swab was taken from every participant. METHODS: Collection of swabs from the infected skin and soft tissues, followed by laboratory testing to phenotypically and genotypically identify MRSA. Also, nasal swabs were taken from every patient to identify MRSA colonization. RESULTS: Staphylococcus aureus strains were identified in 38 (76%) of the 50 clinical isolates. 18 (47.37%) out of the 38 S. aureus strains were resistant to oxacillin and cefoxitin discs, were penicillin binding protein 2a (PBP2a) producers, and were initially diagnosed as MRSA. All of the 18 strains were definitively diagnosed as MRSA by mecA gene detection using real time PCR, while only six (33.33%) strains were PVL positive. Using the sets of primers of Zhang et al.: nine (50%) out of the 18 CA-MRSA strains were SCCmec type V, and one (5.56%) was SCCmec type IVc. Then, using the set of primers by Oliveira et al., two (25%) out of the eight untypable MRSA strains were found to be SCCmec type IV, and six (75%) remained untypable. CONCLUSIONS: CA-MRSA must be considered when treating skin and soft tissue infections, especially in developing countries. Empirical use of agents active against CA-MRSA is warranted for patients presenting with serious SSTIs.

Micelle-enhanced spectrofluorimetric method for determination of cholesterol-reducing drug ezetimibe in dosage forms.

A simple and sensitive spectrofluorimetric method was developed for the determination of ezetimibe in its pharmaceutical formulations. The proposed method is based on investigation of the fluorescence spectral behavior of ezetimibe in sodium dodecyl sulfate (SDS) micellar system. In aqueous solution of acetate buffer pH 5.0, the fluorescence intensity of ezetimibe was greatly enhanced, 200% enhancement, in the presence of SDS. The fluorescence intensity of ezetimibe was measured at 380 nm after excitation at 268 nm. The fluorescence-concentration plot was rectilinear over the range of 0.03-3.0 µg/mL with lower detection limit of 3.08 × 10(-3) µg/mL. The method was successfully applied to the analysis of ezetimibe in its commercial tablets; the results were in good agreement with those obtained with the reported method. The application of the proposed method was extended to the stability studies of ezetimibe after exposure to different forced degradation conditions, such as acidic, alkaline, photo and oxidative conditions, according to ICH guidelines.

Determination of enalapril maleate and atenolol in their pharmaceutical products and in biological fluids by flow-injection chemiluminescence.

A chemiluminescent method using flow injection (FI) was investigated for rapid and sensitive determination of enalapril maleate and atenolol, which are used in the treatment of hypertension. The method is based on the sensitizing effect of these drugs on the Ce(IV)-sulfite reaction. The different experimental parameters affecting the chemiluminescence (CL) intensity were carefully studied and incorporated into the procedure. The method permitted the determination of 0.01-3.0 microg mL(-1) of enalapril maleate in bulk form with correlation coefficient r = 0.99993, lower limit of detection (LOD) 0.0025 microg mL(-1) (S/N = 2) and lower limit of quantitation (LOQ) 0.01 microg mL(-1). The linearity range of atenolol in bulk form was 0.01-2.0 microg mL(-1) (r = 0.99989) with LOD of 0.0003 microg mL(-1) (S/N = 2) and LOQ of 0.01 microg mL(-1). In biological fluids the linearity range of enalapril maleate was 0.1-2.0 microg mL(-1) in both urine and serum, and for atenolol the linearity range was 0.1-1.0 microg mL(-1) in both urine and serum. The method was also applied to the determination of the drugs in their pharmaceutical preparations.

Flow-injection chemiluminometric determination of pioglitazone HCl by its sensitizing effect on the cerium-sulfite reaction.

A flow injection chemiluminescent (FI-CL) method was developed for the determination of pioglitazone HCl. It is based on the sensitizing effect of the drug on the oxidation reaction of sulfite with cerium(IV). The different experimental parameters affecting the chemiluminescence intensity, such as concentration of reagents and some physical parameters of the manifold, were carefully studied and incorporated into the procedure. The method permits the determination of 0.05 - 3.0 microg ml(-1) of pioglitazone HCl with correlation coefficient r = 0.9999. The lower limit of detection (LOD) is 0.01 microg ml(-1) (S/N = 2) and the lower limit of quantitation (LOQ) is 0.05 microg ml(-1). The proposed method was compared with other reported methods and was found to be equally accurate and precise. It was successfully applied to the determination of the drug in pharmaceutical preparations and in biological fluids.

A Validated Adsorptive Stripping Voltammetric Determination of Antidiabetic Agent Pioglitazone HCl in Tablets and Biological Fluids.

Square-wave adsorptive cathodic stripping voltammetry was used to determine pioglitazone HCl in Britton Robinson buffer of pH5. The adsorptive cathodic peak was observed at -1.5 V vs. Ag/AgCl. The peak response was characterized with respect to pH, supporting electrolyte, frequency, scan increment, pulse-amplitude, accumulation potential and pre-concentration time. Under optimal conditions, the peak current is proportional to the concentration of pioglitazone HCl, and a linear calibration graphs were obtained within the concentration levels of 10(-8) and 10(-4) M following different accumulation time periods (0-300 s). The obtained results were analyzed and the statistical parameters were calculated. The detection limit is 8.08 × 10(-9) M (3.17 ng ml(-1)) using 300 s pre-concentration time, whereas the quantitative limit is 2.45 × 10(-8) M (9.63 ng ml(-1)). The proposed method was applied to assay the drug in pharmaceutical formulations and biological fluids. The pharmacokinetic parameters of drug in human plasma were estimated as: C max=785.8 ng ml(-1), t max=1.5 h, K e=0.125 h(-1) and t 1/2=8 h which are favorably compared with those reported in literature.

Spectrofluorometric determination of ketorolac tromethamine via its oxidation with cerium(IV) in pharmaceutical preparations and biological fluids.

A simple and sensitive fluorometric method for determination of ketorolac tromethamine was studied. The method depends on oxidation of the drug with cerium(IV) and subsequent monitoring of the fluorescence of the induced cerium(III) at lambda(em) 365 nm after excitation at 255 nm. Different variables affecting the reaction conditions, such as the concentrations of cerium(IV), sulfuric acid concentration, reaction time, and temperature, were carefully studied and optimized. Under the optimum conditions, a linear relationship was found between the relative fluorescence intensity and the concentration of the investigated drug in the range of 0.1-0.8 microg/mL. No interferences could be observed from the excipients commonly present in dosage forms. The proposed method was successfully applied to the analysis of the investigated drug in its pure form, pharmaceutical preparations, and biological fluids with good accuracy and precision. The recoveries for pharmaceutical formulations ranged from 99.8-101.0 +/- 0.6% for tablets, 98.5-101.0 +/- 1.0% for ampoules, and 99.0-100.5 +/- 0.7% for eye drops. The results obtained by the proposed method were satisfactory compared with those obtained by the official method. The recoveries for biological fluids were 99.1-100.4 +/- 0.7 and 99.0-100.0 +/- 0.5% for plasma and urine, respectively.