Spectrophotometric and spectrofluorimetric methods for determination of certain biologically active phenolic drugs in their bulk powders and different pharmaceutical formulations

Micelle-enhanced spectrofluorimetric method for the rapid determination of bronchodilator terbutaline and its prodrug bambuterol: Application for content uniformity test

A novel, simple and sensitive spectrofluorimetric approach for determination of terbutaline sulphate (TER) and its prodrug bambuterol (BAM) in their pure and pharmaceutical dosage forms was developed. The suggested approach depends on enhancing the native fluorescence of either TER or BAM at 315 and 297.2 nm after excitation at 277 and 259 nm, respectively, using sodium dodecyl sulphate (SDS) as a micellar media. In the presence of 0.7% w/v SDS, about 1.38-fold and 1.18-fold enhancement is achieved in the relative fluorescence intensity (RFI) of TER and BAM, respectively. The fluorescence-concentration curves were rectilinear over the concentration range of 0.8-16 μg mL^-1 , with detection limits (LOD) of 0.252 and 0.26 (μg mL-1), quantitation limits (LOQ) of 0.76 and 0.79 (μg mL-1), determination coefficients (r2) of 0.9981, and slopes of 45.92 and 10.44 for TER and BAM, respectively. The suggested approach was validated in accordance with ICH criteria and was effectively applied in the analysis of the studied drugs in their commercial tablets. The high sensitivity of the proposed approach allows its application in evaluating the content uniformity testing of the studied drugs in their tablets through using the official United States Pharmacopeia criteria (USP). Statistical analogies of the findings with that of the reported methods showed really good harmony and indicated no major differences in precision and accuracy.

Effective removal of doxycycline from aqueous solution using CuO nanoparticles decorated poly(2-acrylamido-2-methyl-1-propanesulfonic acid)/chitosan

The primary focus of the present study was to synthesize CuO nanoparticles decorated poly(2-acrylamido-2-methyl-1-propanesulfonic acid)/chitosan to explore its potential for uptake of doxycycline (DXN) from water. The composite material was characterized using Fourier transform infrared spectroscopy, scanning electron microscopy with energy dispersive X-ray spectroscopy, X-ray diffraction and thermogravimetric analysis-differential thermal analysis. Central composite design under response surface methodology was opted to optimize the process variables (pH, adsorbent dosage, contact time and initial concentration of DXN) for obtaining the highest removal efficiency. The removal of DXN reached 98.84% at 303 K under the optimum conditions of pH 7.0, equilibrating time of 70 min, adsorbent dose of 20 mg/25 mL and initial concentration of 50 mg L-1. The Langmuir isotherm and pseudo-second-order kinetic models fitted best with the experimental data. The values of ΔG° (- 29.159 to - 31.997 kJ mol-1), ΔH° (56.768 kJ mol-1) and ΔS° (283.382 J mol-1 K-1) demonstrated the spontaneous and endothermic nature of adsorption process. The adsorption/desorption study revealed the reusability of the prepared composite material for DXN uptake up to six cycles.

Smartphone Digital Image Using for Determination of DCH by a Diazotization Reaction

Background:

Simple, sensitive, and economic colorimetric device based on a smartphone digital image coupled with Color Grab™ application was developed for DCH drug determination. The method is based on the diazotization reaction of benzocaine with DCH drug to get an orange azo dye.

Methods:

Variable parameters such as volumes of reagents, the internal walls and ambient light have been analyzed and optimized. From the optimized conditions, a calibration curve was created by the effective intensity (IG) of an orange azo dye, a correlation of determination is 0.999 and limit of detection 0.808 mg/L.

Results:

The results of the Smartphone method were statistically compared with the reference method using a t-test and found to be a good agreement.

Conclusion:

This method requires neither solvent extraction and temperature control, also it has achieved an extensive linear range and low limit of detection compared with different methods reported in the literature.

Highly sensitive spectrofluorimetric procedure for the assay of phenothiazine derivatives in the presence of their sulfoxide oxidized product

A validated straightforward and sensitive spectrofluorimetric procedure was developed to assay trifluoperazine hydrochloride, promethazine hydrochloride, and perazine maleate. The procedure was dependent on oxidation of the investigated phenothiazines using a known excess of ammonium cerium sulfate as oxidizing agent and overseeing the fluorescence intensity of the resultant Ce³⁺ ion as the product of this reaction at λ_cx = 254 nm. and λ_em = 355 nm. Various parameters controlling the reaction were investigated and optimized. Linear calibration graphs were found in the general concentration range 5-30 ng/ml with a general correlation coefficient range 0.9994-0.9995. Limits of detection were 0.97, 0.70 and 0.56 ng/ml, whereas limits of quantification were 3.24, 2.12 and 1.89 ng/ml for trifluoperazine hydrochloride, promethazine hydrochloride and perazine maleate, respectively. The procedure was implemented successfully for analyses of the cited drugs in their trade dosage preparations such as tablets and syrups. The effect of possible interference from common excipients and their sulfoxide oxidized product was studied and the procedure showed good recovery of the drugs under study in their available dosage preparations. The possible effect of structure variation of the studied drugs on the experimental conditions and sensitivity observed with each one was also discussed.

Determination of cefixime using a novel electrochemical sensor produced with gold nanowires/graphene oxide/electropolymerized molecular imprinted polymer

Quantitative analysis of antibiotics is very important because these drugs are widely used to prevent or treat various diseases. Cefixime (CEF, a semi-synthetic antibiotic and the third generation of cephalosporin) is a bactericidal medicine that prevents formation of cell walls in bacteria as well as their growth and proliferation. It, thus, causes the death of bacteria. Antibiotics such as CEF are generally determined by chromatography and spectroscopy techniques. Electrochemical sensors are one of the fast, convenient and low-cost tools for measuring this type of compounds. In this research, an electrochemical sensor was constructed by modifying a glassy carbon electrode (GCE) with expanded graphene oxide and gold nanowires, and then its surface was electropolymerized with a molecular imprinted polymeric layer of polyaniline. The morphological characterization of the obtained film was carried out by scanning and transmission electron microscopy (SEM and TEM). The proposed sensor was analytically characterized on the purpose of comparing it to other modified GCEs. The sensor could work linearly for the concentration range of 20.0-950.0 nM and with a limit of detection of 7.1 nM. It was successfully applied to determine CEF traces in biological samples (i.e. serum and urine) with excellent recovery percentages.

Novel kinetic spectrophotometric method for estimation of certain biologically active phenolic sympathomimetic drugs in their bulk powders and different pharmaceutical formulations

A simple, selective and sensitive kinetic spectrophotometric method was described for estimation of four phenolic sympathomimetic drugs namely; terbutaline sulfate, fenoterol hydrobromide, isoxsuprine hydrochloride and etilefrine hydrochloride. This method is depended on the oxidation of the phenolic drugs with Folin-Ciocalteu reagent in presence of sodium carbonate. The rate of color development at 747-760nm was measured spectrophotometrically. The experimental parameters controlling the color development were fully studied and optimized. The reaction mechanism for color development was proposed. The calibration graphs for both the initial rate and fixed time methods were constructed, where linear correlations were found in the general concentration ranges of 3.65×10^-6-2.19×10^-5molL^-1 and 2-24.0μgmL^-1 with correlation coefficients in the following range 0.9992-0.9999, 0.9991-0.9998 respectively. The limits of detection and quantitation for the initial rate and fixed time methods were found to be in general concentration range 0.109-0.273, 0.363-0.910 and 0.210-0.483, 0.700-1.611μgmL^-1 respectively. The developed method was validated according to ICH and USP 30 -NF 25 guidelines. The suggested method was successfully implemented to the estimation of these drugs in their commercial pharmaceutical formulations and the recovery percentages obtained were ranged from 97.63%±1.37 to 100.17%±0.95 and 97.29%±0.74 to 100.14±0.81 for initial rate and fixed time methods respectively. The data obtained from the analysis of dosage forms were compared with those obtained by reported methods. Statistical analysis of these results indicated no significant variation in the accuracy and precision of both the proposed and reported methods.