Analytical methods for the determination of paracetamol, pseudoephedrine and brompheniramine in Comtrex tablets.

Comtrex® tablets composed of paracetamol, pseudoephedrine and brompheniramine are widely used for relieving symptoms related to common cold. This study has overcome the challenging dosage form ratio (250:15:1) and proposed chromatographic methods for analyzing the ternary combination were utilized displaying different apparatus, solvents and sensitivity ranges. Three chromatographic methods namely thin layer chromatography (TLC), high performance liquid chromatography with ultra-violet detection (HPLC-UV) and ultra-performance liquid chromatography coupled to tandem mass spectrometry (UPLC-MS/MS) were developed and validated for the simultaneous determination of the three drugs. Concerning the TLC method, aluminum TLC plates pre-coated with silica gel 60F254 were used and methanol:water:ammonia (9:1:0.1, v/v/v) was applied as a mobile phase; scanning of the plates was carried out at 254 nm. For the HPLC-UV method C18 column was used with an isocratic elution mobile phase composed of water:acetonitrile (75:25, v/v; pH 3.2) and the detection was at 210 nm. For the UPLC-MS/MS method; separation was performed on a UPLC-BEH C18 column with methanol: 0.1% ammonium formate (60:40, v/v) as the mobile phase utilizing diphenhydramine as an internal standard and mass spectrometry was used for detection. The methods were simple, sensitive, accurate and precise. Statistical analysis revealed no significant difference from the reported methods in regard to accuracy and precision.

Analysis of paracetamol, pseudoephedrine and cetirizine in Allercet Cold® capsules using spectrophotometric techniques.

Paracetamol (PAR), Pseudoephedrine hydrochloride (PSE) and cetirizine dihydrochloride (CET) is a ternary mixture that composes tablets which are popular for the relief of flu in Egypt. The spectra of the drugs were overlapped and no spectrophotometric methods were reported to resolve the mixture. This research proposes four spectrophotometric methods that are efficient and require water only as a solvent. The first method was ratio subtraction-ratio difference method (RSDM) where PAR was initially removed from the mixture by ratio subtraction and determined at 292.4 nm, then PSE and CET were quantified by subtracting the amplitudes of their ratio spectra between 257.0 and 230.0 nm for PSE and between 228.0 and 257.0 nm for CET. The second method was derivative ratio spectra-zero crossing (DRZC) which was based on determining both PSE and CET from the zero-crossing points of the first and third derivative of their ratio spectra at 252.0 and 237.0 nm, respectively while PAR was determined using its first derivative at 292.4 nm. Moreover, the ternary mixture was resolved using successive derivative ratio (SDR) method where PAR, PSE and CET were determined at 310.2, 257.0 and 242.4 nm, respectively. The fourth proposed method was pure component contribution algorithm (PCCA) which was applied to quantify the drugs at their λmax. Recovery percentages for RSDM were 100.7 ± 1.890, 99.69 ± 0.8400 and 99.38 ± 1.550; DRZC were 101.8 ± 0.8600, 99.04 ± 1.200 and 98.95 ± 1.300; SDR were 101.9 ± 1.060, 99.59 ± 1.010 and 100.2 ± 0.6300; PCCA were 101.6 ± 1.240, 99.10 ± 0.5400 and 100.4 ± 1.800 for PAR, PSE and BRM; respectively. The suggested methods were effectively applied to analyze laboratory prepared mixtures and their combined dosage form.

Chromatographic Analysis of a Multicomponent Mixture of B1, B6, B12, Benfotiamine, and Diclofenac; Part I: HPLC and UPLC Methods for the Simultaneous Quantification of These Five Components in Tablets and Capsules.

New, simple, highly sensitive, precise, and accurate gradient reversed-phase chromatographic methods were developed using HPLC and ultra-HPLC (UPLC) systems for the determination of five components, namely thiamine, pyridoxine, cyanocobalamin, benfotiamine, and diclofenac in tablets and capsules. The methods were compared for their efficiency in the separation and determination of these five compounds using two different C18 columns (250 × 4.6 mm, 5 µm; and 100 × 4.6 mm, 2.6 µm) for HPLC and UPLC, respectively. Chromatographic separation was performed with a mobile phase containing acetonitrile and 0.025 M phosphate buffer (pH 3.5), with a gradient program and a flow rate of 1.5 and 1.0 mL/min for both methods, respectively. The methods were validated according to International Conference on Harmonization guidelines. Linearity was achieved in the range of 5.00 to 150.00 µg/mL for each of the five compounds. Ruggedness and intermediate precision were confirmed by different analysts on different columns on different days. Moreover, the components were subjected to an accelerated stability study under acidic, alkaline, and oxidative stress conditions and no interfering peaks were observed. The five compounds were efficiently separated in <20 min by HPLC, whereas for UPLC, separation was achieved in <8 min, which dramatically decreased the consumption of organic solvents.

A novel pure component contribution algorithm (PCCA) for extracting components' contribution from severely overlapped signals; an application to UV-spectrophotometric data.

A novel, simple and accurate algorithm capable of extracting the contribution of each component from a mixture signal where the components are completely overlapped was developed. It is based on the development of a coded function which eliminates the signal of interfering components using mean centering as a processing tool; finally the pure contribution of each component is extracted. The algorithm allows the determination of each component as a single one. It was validated by the use of simulated data set of three overlapped signals and tested against simulated random noise. Two fit values were developed and calculated for optimization, one to test that that the absorptivity values of the extracted spectra are within the confidence limits of the slope and the other is the correlation between the pure and extracted spectra. It has been successfully applied to real UV data of binary mixture of Ibuprofen and Paracetamol and ternary mixture of Amiloride hydrochloride, Atenolol and Hydrochlorothiazide in tablets and capsules, respectively. The results were compared to previously reported separation method and no significant difference was found regarding both accuracy and precision.

Determination of a novel ACE inhibitor in the presence of alkaline and oxidative degradation products using smart spectrophotometric and chemometric methods.

Simple, accurate, sensitive and validated UV spectrophotometric and chemometric methods were developed for the determination of imidapril hydrochloride (IMD) in the presence of both its alkaline (AKN) and oxidative (OXI) degradation products and in its pharmaceutical formulation. Method A is the fourth derivative spectra (D4) which allows the determination of IMD in the presence of both AKN and OXD, in pure form and in tablets by measuring the peak amplitude at 243.0 nm. Methods B, C and D, manipulating ratio spectra, were also developed. Method B is the double divisor-ratio difference spectrophotometric one (DD-RD) by computing the difference between the amplitudes of IMD ratio spectra at 232 and 256.3 nm. Method C is the double divisor-first derivative of ratio spectra method (DD-DR1) at 243.2 nm, while method D is the mean centering of ratio spectra (MCR) at 288.0 nm. Methods A, B, C and D could successfully determine IMD in a concentration range of 4.0-32.0 µg/mL. Methods E and F are principal component regression (PCR) and partial least-squares (PLS), respectively, for the simultaneous determination of IMD in the presence of both AKN and OXI, in pure form and in its tablets. The developed methods have the advantage of simultaneous determination of the cited components without any pre-treatment. The accuracy, precision and linearity ranges of the developed methods were determined. The results obtained were statistically compared with those of a reported HPLC method, and there was no significant difference between the proposed methods and the reported method regarding both accuracy and precision.

Simultaneous determination of some cholesterol-lowering drugs in their binary mixture by novel spectrophotometric methods.

Four simple, specific, accurate and precise spectrophotometric methods manipulating ratio spectra were developed and validated for simultaneous determination of simvastatin (SM) and ezetimibe (EZ) namely; extended ratio subtraction (EXRSM), simultaneous ratio subtraction (SRSM), ratio difference (RDSM) and absorption factor (AFM). The proposed spectrophotometric procedures do not require any preliminary separation step. The accuracy, precision and linearity ranges of the proposed methods were determined, and the methods were validated and the specificity was assessed by analyzing synthetic mixtures containing the cited drugs. The four methods were applied for the determination of the cited drugs in tablets and the obtained results were statistically compared with each other and with those of a reported HPLC method. The comparison showed that there is no significant difference between the proposed methods and the reported method regarding both accuracy and precision.

Quantitative analysis of the cholesterol-lowering drugs ezetimibe and simvastatin in pure powder, binary mixtures, and a combined dosage form by spectrophotometry, chemometry, and high-performance column liquid chromatography.

Simple, accurate, sensitive, and precise UV spectrophotometric, chemometric, and HPLC methods were developed for simultaneous determination of a two-component drug mixture of ezetimibe (EZ) and simvastatin (SM) in laboratory-prepared mixtures and a combined tablet dosage form. Four spectrophotometric methods were developed, namely, ratio spectra derivative, ratio subtraction, isosbestic point, and mean centering of ratio spectra. The developed chemometric-assisted spectrophotometric method was the concentration residual augmented classical least-squares method; its prediction ability was assessed and compared to the conventional partial least-squares method. The developed HPLC method used an RP ZORBAX C18 column (5 microm particle size, 250 x 4.6 mm id) with isocratic elution. The mobile phase was acetonitrile-pH 3.5 phosphate buffer (40 + 60, v/v) at a flow rate of 1.0 mL/min, with UV detection at 230 nm. The accuracy, precision, and linearity ranges of the developed methods were determined. The developed methods were successfully applied for determination of EZ and SM in bulk powder, laboratory-prepared mixtures, and a combined dosage form. The results obtained were compared statistically with each other and to those of a reported HPLC method; there was no significant difference between the proposed methods and the reported method regarding both accuracy and precision.

Validated stability-indicating TLC method for the determination of noscapine.

A sensitive, selective, precise and stability-indicating thin-layer chromatographic (TLC) method was developed and validated for the analysis of noscapine, both as a bulk drug and in its formulation. The method employed TLC aluminium plates precoated with silica gel 60F-254 as the stationary phase. The solvent system consisted of chloroform-methanol (10:0.5 v/v). Densitometric analysis of noscapine and its degradation products was carried out in the absorbance mode at 254 nm. This system was found to give compact symmetrical spots for noscapine (R(f) value 0.85 +/- 0.04). Noscapine was subjected to acid and alkali hydrolysis, oxidation and photo degradation. The drug undergoes photo degradation and also degrades under acidic and basic conditions. The prepared degradation products were identified and verified through infrared (IR) and mass spectral analyses. The degraded products were also well resolved from the pure drug with significantly different R(f) values and they were quantitatively determined. The method was validated for linearity, precision, robustness, limit of detection (LOD), limit of quantitation (LOQ), specificity and accuracy. Linearity was found to be in the 1.0-10.0 microg, 0.4-3.2 microg, 1.0-9.0 microg and 0.5-5.0 microg/band ranges for noscapine, cotarnine, meconine and opionic acid, respectively. The polynomial regression analysis for the calibration plots showed a good polynomial relationship with r(2) of 0.9998, 9989, 9996 and 0.9997 for noscapine and its three degradation products, cotarnine, meconine and opionic acid, respectively. Statistical analysis proves that the method is repeatable and specific for the estimation of noscapine. As this approach could effectively separate the drug from its degradation products it can be employed as a stability-indicating method in Quality Control laboratories.