Samia M. El-Gizawy

Univariate versus Multivariate Spectrophotometric Methods for Simultaneous Determination of Complex Binary Mixtures with Overlapped Spectra: A Comparative Study

Two novel simple and accurate univariate spectrophotometric methods were described for the determination of a binary mixture of Sodium cromoglicate (SCG) and Fluorometholone (FLU) namely; ratio subtraction coupled with extended ratio subtraction (RS-EXRSM) and constant center (CCSM) spectrophotometric methods. The methods were able to recover the zero order absorption spectra of both drugs from their binary mixture through simple mathematical calculations. The linearity ranges were found to be (2.5–25 µg/mL) and (4- 25 µg/mL) for SCG and FLU, respectively. A comparative study was conducted between the proposed univariate methods versus multivariate ones, based on using principle component regression (PCR) and partial least squares (PLS-2). Upon applying the methods for the determination of SCG and FLU in laboratory prepared mixtures, the (CCSM and PLS-2) proved to be of higher predictive ability rather than (RS-EXRSM and PCR) in prediction of mixtures containing low concentration of one of the components. The proposed methods were validated in compliance with the ICH guidelines. These methods could be alternative to different HPLC techniques in quality control laboratories lacking the required facilities for those expensive techniques

HPLC Analysis of Metronidazole and Diloxanide Furoate in Its Dosage Forms

Abstract A high performance liquid chromatographic method for the simultaneous determination of metronidazole and diloxanide furoate in single and combined dosage form has been developed. Each drug acted as internal standard for the other. Both of the drugs eluted from the cyclobond column (β-cyclodextrin stationary phase) without retardation effects, using methanol-0.05 M NaH2PO4 (pH 7) in ratio 35:65, flow rate 1 ml min−1 and detection at 254 nm. Metronidazole and diloxanide furoate gave rectilinear calibration graphs in the ranges 1–10 μg and 1–5 μg respectively. Recoveries were in the range 99.6 to 101.3% and their corresponding coefficient of variation are 0.7 and 1.05% (n=6).

High Performance Liquid Chromatographic Determination of Multivitamin Preparations Using a Chemically Bonded Cyclodextrin Stationary Phase

Abstract A high performance liquid chromatographic procedure for simultaneous determination of water-soluble vitamin preparations containing pyridoxine hydrochloride (Vit. B6, cyanocobalamin (Vit. B12), thiamine hydrochloride (Vit. B1) and folic acid using a cyclobond I column was developed. The four vitamins were assayed in multivitamin pharmaceutical formulations not containing minerals. Samples were chromatographed using pH 7 phosphate buffer: methanol (80 : 20 %) mobile-phase. The procedure is rapid and the total chromatographic time does not exceed 6.64 min. The method is accurate, precise and specific.

COMPARATIVE STUDY OF NEW SPECTROPHOTOMETRIC METHODS; AN APPLICATION ON PHARMACEUTICAL BINARY MIXTURE OF CIPROFLOXACIN HYDROCHLORIDE AND HYDROCORTISONE

ABSTRACT Simple, specific, accurate and precise spectrophotometric methods were developed and validated for simultaneous estimation of Ciprofloxacin hydrochloride (CIP) and Hydrocortisone (HYD) in their pure form and pharmaceutical dosage form. Two new spectrophotometric methods were applied: extended ratio subtraction (EXRSM) and ratio difference (RDSM) methods. The results were compared to three well-established methods: Mean centering of ratio spectra method (MCR), Isoabsorpative point spectrophotometric method (IsoM) and Absorbance ratio method (ARM). The linearity range for the spectrophotometric methods was found to be (2-14 µg/mL) and (1-14 µg/mL) for CIP and HYD respectively. The selectivity of the developed methods was investigated by analyzing laboratory prepared mixtures of the two drugs and their combined dosage form. The results obtained from the proposed methods were statistically compared using one-way analysis of variance (ANOVA) where no significant difference was observed between the new (EXRSM and RDSM) and the well-established methods which prove their validity for the analysis of this binary mixture. The methods were validated as per ICH guidelines regarding accuracy, precision, repeatability and robustness; which were found to be within the acceptable limits. The new methods were simple, sensitive and don’t need a special program, so they could be easily applied as alternative methods to LC methods in quality control laboratories lacking the required facilities for those techniques.

Simultaneous determination of free and bound adriamycin, adriamycinol, adriamycinone and duanorubicin in plasma using column-switching technique and protein-coated pre-columns☆

Adriamycin, adriamycinol, adriamycinone and duanorubicin were simultaneously determined by the development of an on-line plasma clean-up system. A short protein-coated Lichrosorb, RP-8, RP-2, CN and muBondapak phenyl as well as ODS silica have been examined for their performance as pre-columns. The drugs and metabolites were separated from weakly retained plasma components through two steps; phosphate buffer saline, pH 7.4 and 15% acetonitrile in 0.1 M sodium dihydrogen phosphate, pH 3. The chromatographic conditions were: ODS/TM column, flow rate 1 ml/min, 35% acctonitrile in 0.1 M sodium dihydrogen phosphate (pH 3) containing 0.3% heptafluorobutyric acid as mobile phase. The detection was carried out using fluorescence monitor operated at an emission 555 nm and excitation 460 nm. Good resolution was obtained within 13 min. This method is reproducible for analysis of drugs and metabolites (99.3-100.1%, CV < 2%) in plasma.

Cyclodextrin Bonded Phase for Liquid Chromatographic Separation and Analysis of Some Oral Contraceptives

Abstract A specific and sensitive analytical HPLC procedure was described for quantitative determination of ethinylestradiol and norethisterone acetate (Anovlar 1) and ethinylestradiol and norgestrel (Primovlar) in tablet formulation. These steroids were extracted from the tablets with methanol. The steroids were then determined with high performance liquid Chromatograph-Cyclobond 1 column using mobile phase phosphate buffer pH 7.0: methanol (60:40), flow rate 0.5 ml min−1 and the detection was effected spectrophotometrically at 280 nm, using variable wavelength UV detector. There was > 99.3% recovery from synthetic mixtures and the coefficient of variation was < 2.0% for the formulations investigated. The method is highly quantitative and reproducible.

High-performance liquid chromatographic determination of mepyramine maleate, pheniramine maleate and phenylpropanolamine hydrochloride in tablets and drops.

HPLC with a chemically bonded β-cyclodextrin (Cyclobond I) column was used for the separation and determination of mepyramine maleate, pheniramine maleate and phenylpropanolamine hydrochloride in dosage forms. The intact compounds were separated and determined in standard mixtures and in selected pharmaceutical dosage forms. All three active ingredients in tablets and oral drops can be separated by HPLC; caffeine in timed-release tablets was determined by spectrophotometry after TLC separation from interfering components.

Ultrasensitive spectrofluorimetric method for rapid determination of daclatasvir and ledipasvir in human plasma and pharmaceutical formulations

&NA; Direct‐acting antivirals (DAAs) represent a revolution in the treatment of chronic hepatitis C which have emerged at an extremely rapid pace over the past few years. DAAs act directly on the hepatitis C virus at various points in the viral life cycle to inhibit viral production. Among these novel DAAs, are daclatasvir (DCS) and ledipasvir (LDS). Herein, a novel, fast, simple, ultrasensitive and cost‐effective spectrofluorimetric method was designed for determination of DCS and LDS in miscellaneous matrices. The method is based on investigation of the native fluorescence of the cited drugs. The relative fluorescence intensity (RFI) was measured at &lgr;ex/&lgr;em equal to 315/381 nm for DCS and 332/387 nm for LDS. Under the optimum conditions, the linear ranges of calibration curves were 0.2–30 and 6–120 ng mL−1 for DCS and LDS, respectively with correlation coefficients ≥0.9998. The detection limits were 0.047 and 1.939 ng mL−1 for DCS and LDS, respectively indicating ultrasensitivity of the proposed method. Consequently, this permits in vitro and in vivo application of the proposed method in spiked and real human plasma with good percentage recovery (96.6–103.6%). The method was validated in compliance with ICH guidelines and US‐FDA guidelines. Furthermore, the application was extended to analysis of DCS and LDS in its pharmaceutical formulations (either alone or in presence of other co‐formulated drugs) and in synthetic mixture with sofosbuvir or ribavirin.

Thin layer chromatography–densitometric determination of some non-sedating antihistamines in combination with pseudoephedrine or acetaminophen in synthetic mixtures and in pharmaceutical formulations

The combination of certain non-sedating antihistamines (NSA) such as fexofenadine (FXD), ketotifen (KET) and loratadine (LOR) with pseudoephedrine (PSE) or acetaminophen (ACE) is widely used in the treatment of allergic rhinitis, conjunctivitis and chronic urticaria. A rapid, simple, selective and precise densitometric method was developed and validated for simultaneous estimation of six synthetic binary mixtures and their pharmaceutical dosage forms. The method employed thin layer chromatography aluminum plates precoated with silica gel G 60 F254 as the stationary phase. The mobile phases chosen for development gave compact bands for the mixtures FXD-PSE (I), KET-PSE (II), LOR-PSE (III), FXD-ACE (IV), KET-ACE (V) and LOR-ACE (VI) [Retardation factor (Rf ) values were (0.20, 0.32), (0.69, 0.34), (0.79, 0.13), (0.36, 0.70), (0.51, 0.30) and (0.76, 0.26), respectively]. Spectrodensitometric scanning integration was performed at 217, 218, 218, 233, 272 and 251 nm for the mixtures I-VI, respectively. The linear regression data for the calibration plots showed an excellent linear relationship. The method was validated for precision, accuracy, robustness and recovery. Limits of detection and quantitation were calculated. Statistical analysis proved that the method is reproducible and selective for the simultaneous estimation of these binary mixtures.

Simultaneous Determination of Diazepam, Oxazepam and Temazepam in Spiked Urine By Hplc

ABSTRACT|Oxazepam and temazepam are two minor metabolites of diazepam. These three benzodiazepines may be found in presence of each other in biological fluids. Therefore, in this study an HPLC method was developed to separate and analyze them. Benzodiazepines have ability to form inclusion complexes with p-cyclodextrin (β-CyD). According to the degree of binding constant with β-CyD, these compounds can be separated by β-CyD bound to silica (cyclobond column) as the stationary phase using HPLC. The development and validation of the HPLC procedure for the separation and determination of these compounds in mixtures were studied. The mobile-phase system consisted of phosphate buffer (pH 7): methanol [75:25], with flow rate 0.8 ml min−1 and UV detection at 240 nm was used. The calibration graphs were rectilinear from 0.1-2.5 μg/ml and coefficients of variation were <2% for the three compounds in bulk forms. The method was used to analyse these bezodiazepines in spiked urine containing all three compounds in combination. Recoveries were 97-99.8% The limit of detection and limit of quantitation were 0.05 μg/ml and 0.1 μg/ml, respectively. The described method is selective, rapid, simple, reproducible and accurate.