Sonia T. Hassib

Validated stability-indicating derivative and derivative ratio methods for the determination of some drugs used to alleviate respiratory tract disorders and their degradation products

Derivative and derivative ratio methods are presented for the determination of butamirate citrate, formoterol fumarate, montelukast sodium, and sodium cromoglycate. Using the second derivative ultraviolet (UV) spectrophotometry, butamirate citrate and formoterol fumarate were determined by measuring the peak amplitude at 260.4 and 261.8 nm, respectively, without any interference of their degradation products. Butamirate citrate degradation product, 2-phenyl butyric acid, was determined by the measurement of its second derivative amplitude at 246.7 nm where butamirate citrate displays zero crossing. Formoterol fumarate degradation product, desformyl derivative, could be evaluated through the use of the first derivative at peak amplitude of 264.8 nm where interference of formoterol fumarate is negligible. In the first mode, the zero-crossing technique was applied at 305 nm for the determination of montelukast sodium in the presence of its photodegradation product, cis-isomer. The derivative of ratio spectra of montelukast sodium and its cis- isomer were used to determine both isomers using the first derivative of the ratio spectra by measuring the amplitudes of the trough at 305 nm and the peak at 308 nm, respectively. The later technique was also used for the determination of a ternary mixture of sodium cromoglycate and its two degradation products using zero-crossing method. In the derivative ratio spectra of the ternary mixture, trough depths were measured at 271.6, 302.8 and 302.2 nm, using the second, the first, and the second mode to evaluate sodium cromoglycate, degradation product (1) and degradation product (2), respectively. All the methods were applied successfully to the pharmaceutical preparation and were validated according to ICH guidelines.

Reversed-Phase High Performance Liquid Chromatographic and Thin Layer Chromatographic Methods for the Simultaneous Determination of Benazepril Hydrochloride and Hydrochlorothiazide in Cibadrex Tablets

ABSTRACT Two procedures were developed for simultaneous determination of benazepril hydrochloride (I) and hydrochlorothiazide (II) in pure, laboratory made mixtures and in pharmaceutical dosage form “Cibadrex tablets® using reversed phase high performance liquid chromatographic and thin layer chromatographic methods. For reversed phase HPLC, a new very sensitive, rapid, selective method was developed. The linearity ranges were 32-448 ng/20 μl and 40-560 ng/20 μl for benazepril hydrochloride and hydrochlorothiazide, respectively. The corresponding recoveries were 99.38 ± 1.526 and 99.2 ± 1.123. The minimum detection limits were 7 ng/20 μl and 14 ng/20 μl for benazepril hydrochloride and hydrochlorothiazide respectively. On the other hand, a new, simple, sensitive and fast thin layer chromatographic scanning densitometric method was developed for simultaneous determination of benazepril hydrochloride and hydrochlorothiazide using ethyl acetate: methanol: ammonia (85: 20: 10 v/v) as the developing system. The Rf values were 0.33 & 0.68 for benazepril hydrochloride and hydrochlorothiazide respectively. The minimum detection limit obtained was 0.12 μg/spot for benazepril hydrochloride and 0.24 μg/spot for hydrochlorothiazide. The mean percentage recoveries were 100.04 ± 1.102 and 99.31 ± 1.009 for benazepril hydrochloride and hydrochlorothiazide respectively. The two proposed methods were simple, precise, sensitive and could be successfully applied for the determination of pure, laboratory made mixtures and pharmaceutical dosage forms. The results obtained were compared with those obtained by A 1%.

Derivative Spectrophotometric Determination of Levodopa and Benserazide Hydrochloride

Abstract First-derivative spectrophotometry is used to evaluate a mixture containing levodopa and benserazide hydrochloride. Levodopa is determined by zero-crossing measurement at 267 nm. The height of the valley at 232 nm is used to calculate the amount of benserazide hydrochloride in mixture. Second-derivative mode is also used to estimate the amount of levodopa. Both drugs are successfully determined in Madopar capsules using first-derivative mode.

DETERMINATION OF CERTAIN ANTISPASMODIC DRUGS AS SINGLE INGREDIENT, MEBEVERINE HYDROCHLORIDE, AND IN TWO COMPONENT MIXTURES, MEBEVERINE HYDROCHLORIDE–SULPIRIDE AND ISOPROPAMIDE IODIDE–TRIFLUOPERAZINE HYDROCHLORIDE

ABSTRACT Two simple and sensitive methods are described for the quantitative determination of mebeverine hydrochloride as single ingredient. The first method depends on the application of quantitative 1H-NMR spectroscopy using deuterated chloroform and hexamine as an internal reference standard. The second method is based on measuring the native fluorescence of mebeverine hydrochloride in 0.1 N sulphuric acid at 360 nm with excitation at 290 nm. Furthermore simultaneous determinations of two component mixtures, mebeverine hydrochloride with sulpiride and isopropamide iodide with trifluoperazine hydrochloride are presented using first-derivative and second-derivative UV-spectrophotometry, respectively. The proposed methods have been successfully applied to the determination of the cited drugs in commercial tablets. Compared with the reference methods, the proposed methods are more sensitive, with good accuracy and reproducibility.

Sepectrometric Determination of Madopar Capsules

Abstract Levodopa is determined in the presence of benserazide hydrochloride by a sensitive, simple and precise ultraviolet absorption method, recording absorbance in 0.05 M borax solution at 281, 287 and 293 nm. An equation has been used to obtain the correct absorbance at 287 nm. An accurate and specific proton magnetic resonance (PMR) procedure is proposed to quantify benserazide hydrochloride in admixture with levodopa using dimethylsulfoxide to separate the two components, and for quantitative measurements. The estimation of both drugs in Madopar capsules can be achieved successfully using the methods presented.

Determination of Some Anti-Inflammatory Drugs by Derivative Spectrophotometry

Abstract A sensitive and selective derivative spectrophotometric method is employed to quantify two N(4-quinolinyl) anthranilic acid derivatives. The method is based upon measuring the decrease in the ordinate value at 375nm and 372nm, displayed by the first derivative spectra of floctafenine and glafenine, after the addition of p-chloranilic acid. Propyphenazone is determined in the presence of adiphenine hydrochloride using first and second modes. The methods proposed are successfully applied for the determination of the aforementioned drugs in their pharmaceutical formulations.

Qualitative and quantitative analysis of uracil anticancer drugs

Two uracil anticancer drugs can be selectively identified and estimated by means of two colour reactions. 5-Fluorouracil is treated with bromine water in borax medium, and then with 2,4-dinitrophenylhydrazine in acidic medium to give an orange-red precipitate which produces a distinctly violet solution when treated with potassium hydroxide solution. Uracil mustard, containing alkylating groups, is heated with alpha-picoline in aqueous solution. The quaternary salt thus produced is condensed in alkaline medium with sodium 1,2-naphthoquinone-4-sulphonate, giving a pink colour. The possibility of using these colour tests for the determinations of these anticancer drugs in pure and dosage forms has been studied.

Simultaneous determination of timolol maleate in combination with some other anti-glaucoma drugs in rabbit aqueous humor by high performance liquid chromatography-tandem mass spectroscopy.

In this work, a sensitive, selective, accurate and precise LC-MS/MS method has been developed for the simultaneous determination of an anti-glaucoma ß-blocker, timolol maleate (TIM) with other co-administered anti-glaucoma drugs of different classes, namely; dorzolamide hydrochloride (DOR), brinzolamide (BRZ) and brimonidine tartrate (BRM) in rabbit aqueous humor (AH) using eslicarbazepine as an internal standard (IS). Liquid-liquid extraction was used for the purification and pre-concentration of analytes from rabbit AH matrix. The chromatographic separation was achieved using a mobile phase consisting of 10mM ammonium formate pH=7: methanol: acetonitrile (5: 50: 45, v/v/v) in isocratic mode of elution at a flow rate of 0.8mL/min on an INERTSIL(®) C18 ODS-3 column (150mm×4.6mm, 3.5μm). The method was operated using electrospray ionization source in the positive ionization mode prior to detection by multiple reaction monitoring (MRM) at the following transitions: m/z 317.2→261.0 for TIM, m/z 325.1→199.0 for DOR, m/z 384.2→281.0 for BRZ, m/z 292.1→212.0 for BRM and m/z 255.0→237.0 for IS. The separation was done in only 3min and the lower limit of quantitation (LLOQ) was (50ng/ml) for all cited drugs. A detailed validation of the bio-analytical method was performed as mentioned in US-FDA and EMA guidelines and the standard calibration curves were found to be linear in the range (50-5000ng/ml) for all drugs with good mean regression coefficient for all drugs.

Simultaneous HPLC Determination of Betamethasone Esters-Containing Mixtures: Analysis of Their Topical Preparations

Topical pharmaceutical preparations containing betamethasone esters are widely prescribed for treatment of severe inflammatory skin conditions. Some betamethasone esters-containing preparations are formulated with either an antibacterial or an antifungal agent or a vitamin D3 derivative. A fast reversed-phase high-performance liquid chromatography method has been developed for the simultaneous determination of three betamethasone esters-containing binary mixtures along with the excipients of their dosage forms using clobetasone butyrate as internal standard. The first mixture was betamethasone valerate and fusidic acid (Mixture I) with chlorocresol as preservative. The second mixture was betamethasone dipropionate (BTD) and clotrimazole (Mixture II) with benzyl alcohol as preservative. The third mixture was BTD and calcipotriol monohydrate (Mixture III). Optimized chromatographic separation was achieved on a Discovery® C18 (4.6 × 250 mm, 5 μm) column, using water: acetonitrile (35:65, v/v) as mobile phase at flow rate of 1 mL/min with UV detection at 230 nm. The method was validated according to ICH guidelines. The regression coefficients were > 0.999 for all drugs. The method was successfully applied for the determination of the studied drugs in bulk, synthetic mixtures and dosage forms. The developed method is accurate, sensitive, selective and precise and can be used for routine analysis in quality control laboratories.

Determination of four antiepileptic drugs in plasma using ultra-performance liquid chromatography with mass detection technique

Status epilepticus (SE) is considered the second most frequent neurological emergency. Its therapeutic management is performed using sequential antiepileptic drug regimens. Diazepam (DIA), midazolam (MID), phenytoin (PHT) and phenobarbital (PB) are four drugs of different classes used sequentially in the management of SE. A sensitive, selective, accurate and precise method was developed and validated for simultaneous determination of the four antiepileptic drugs in human plasma. Their separation and quantification were achieved using ultra-performance liquid chromatography (UPLC) with mass detection using carbamazepine as internal standard (IS). For the first three drugs and the IS, UPLC-MS/MS with electrospray ionization working in multiple reaction monitoring mode was used at the following transitions: m/z 285 → 193 for DIA; m/z 326 → 291 for MID; m/z 253 → 182 for PHT; and m/z 237 → 194, 237 → 192 for IS. For the fourth drug (PB), a molecular ion peak of PB [M + H] + at m/z 233 was used for its quantitation. The method was linear over concentration ranges 5-500 ng/mL for DIA and MID and 0.25-20 μg/mL for PHT and PB. Bioanalytical validation of the developed method was carried out according to European Medicines Agency guidelines. The developed method can be applied for routine drug analysis, therapeutic drug monitoring and bioequivalence studies.