Simultaneous determination of amiloride and furosemide in pharmaceutical formulations by first digital derivative spectrophotometry

Application of data-intelligence algorithms for modeling the compaction performance of new pharmaceutical excipients

Background

Pharmaceutical excipient development is an extensive process requiring a series of pre-formulation studies to evaluate their performance. The present study compares the conventional compaction and compression pre-formulation studies with artificial intelligence (AI) modeling to predict the performances of thermally and chemically modified starches obtained from Livingstone potato.

Results

The native starch was modified by three methods, and we obtained the following starches; pregelatinized starch (PS), ethanol dehydrated pregelatinized starch (ES), and acid hydrolyzed starch (AS). Microcrystalline cellulose (Avicel® PH101) was employed as a reference since its use in tablet direct compression has been established. The role of compaction pressure on the degree of volume reduction of the tablets was studied using Kawakita and Heckel models which highlighted that when the starch is modified by pregelatinization followed by ethanol dehydration, and/and or acid hydrolysis modification, a directly compressible starch can be obtained that can plastically deform. The data-intelligence results indicated the reliability of the AI-based models over the linear models. Hence, the comparative results demonstrated that the Adaptive neuro-fuzzy inference system (ANFIS) outperformed the other two models in modeling the performance of all of the four excipients with considerable performance accuracy.

Conclusion

The compressibility indices have shown matching characteristics of AS and ES to Avicel® PH101 in terms of direct compressibility potential than PS. Moreover, the data intelligence modeling demonstrates the reliability and satisfactory of ANFIS as a hybrid model over the other two models with increased performance skills in modeling the compaction properties of these novel pharmaceutical excipients.

Multicomponent spectrometric analysis of drugs and their preparations

Pharmaceutical preparations may contain a single ingredient or multi-ingredients as well as excipients. In multicomponent systems, specific analytical methods are required to determine the concentrations of individual components in the presence of interfering substances. Ultraviolet and visible spectrometric methods have widely been developed for the analysis of drugs in mixtures and pharmaceutical preparations. These methods are based on ultraviolet and visible multicomponent analysis and chemometrics (multivariate data analysis). The commonly used chemometric methods include principal component analysis (PCA); regression involving classical least squares (CLS), partial least squares (PLS), inverse least squares (ILS), principal component regression (PCR), multiple linear regression (MLR), artificial neural networks (ANNs); soft independent modeling of class anthology (SIMCA), PLS-discriminant analysis (DA); and functional data analysis (FDA). In this chapter, the applications of multicomponent ultraviolet and visible, derivative, infrared and mass spectrometric and spectrofluorimetric methods to the analysis of multi-ingredient pharmaceutical preparations, biological samples and the kinetics of drug degradation have been reviewed. Chemometric methods provide an efficient solution to calibration problems in the analysis of spectral data for the simultaneous determination of drugs in multicomponent systems. These methods facilitate the assessment of product quality and enhance the efficiency of quality control systems.

Modern kinetic spectrophotometric procedure for estimation of furosemide drug as bulk form and in pharmaceuticals preparations

A simple, rapid, sensitive, inexpensive and easy to perform kinetic spectrophotometric procedure for the investigation of trace quantities of the drug, furosemide (FRO), as bulk and in the pharmaceutical preparations, has been improved upon. The enhanced method was depended on the fashioning of the Schiff ‘s base by the reaction of the aldehyde group present in the 5-sulfo salicylaldehyde reagent, and the primary amino group present in furosemide. The latter acts as a ligand for the formation of an intense colored complex with Co(II) in an acidic medium, with maximum absorption at 608 nm. In the work, kinetic spectrophotometrics were established through the fixed time method. Moreover, Beer’s law was applied on the range of concentration between 5-100 ppm, while the molar absorptivity and the Sandell sensitivity were 3.9295×104 l.mol−1cm−1, 0.008 μg.cm−2, respectively. The detection limit (LOD) was 2.133 µg/ml−1, and LOQ was 1.105 µg/ml−1. Ideal circumstances for all colour improvement were seen, and the suggested procedure has been effectively employed in investigating amounts of furosemide (FRO) in bulk forms and in pharmaceutical preparations (tablets, injection sample). Additives and general excipient materials did not affect the studied method. A statistical comparison between the results that were obtained from the reference method gave good agreement.

Validation of different spectrophotometric methods for determination of vildagliptin and metformin in binary mixture

New, simple, specific, accurate, precise and reproducible spectrophotometric methods have been developed and subsequently validated for determination of vildagliptin (VLG) and metformin (MET) in binary mixture. Zero order spectrophotometric method was the first method used for determination of MET in the range of 2-12 μg mL(-1) by measuring the absorbance at 237.6 nm. The second method was derivative spectrophotometric technique; utilized for determination of MET at 247.4 nm, in the range of 1-12 μg mL(-1). Derivative ratio spectrophotometric method was the third technique; used for determination of VLG in the range of 4-24 μg mL(-1) at 265.8 nm. Fourth and fifth methods adopted for determination of VLG in the range of 4-24 μg mL(-1); were ratio subtraction and mean centering spectrophotometric methods, respectively. All the results were statistically compared with the reported methods, using one-way analysis of variance (ANOVA). The developed methods were satisfactorily applied to analysis of the investigated drugs and proved to be specific and accurate for quality control of them in pharmaceutical dosage forms.

Native fluorescent detection with sequential injection chromatography for doping control analysis

BACKGROUND

Sequential injection chromatography (SIC) is a young, ten years old, separation technique. It was proposed with the benefits of reagent-saving, rapid analysis, system miniaturization and simplicity. SIC with UV detection has proven to be efficient mostly for pharmaceutical analysis. In the current study, a stand-alone multi-wavelength fluorescence (FL) detector was coupled to an SIC system. The hyphenation was exploited for developing an SIC-FL method for the separation and quantification of amiloride (AML) and furosemide (FSM) in human urine and tablet formulation.

RESULTS

AML and FSM were detected using excitation maxima at 380 and 270 nm, respectively, and emission maxima at 413 and 470 nm, respectively. The separation was accomplished in less than 2.0 min into a C18 monolithic column (50 × 4.6 nm) with a mobile phase containing 25 mmol/L phosphate buffer (pH 4.0): acetonitrile: (35:65, v/v). The detection limits were found to be 12 and 470 ng/mL for AML and FSM, respectively.

CONCLUSIONS

The proposed SIC-FL method features satisfactory sensitivity for AML and FSM in urine samples for the minimum required performance limits recommended by the World Anti-Doping Agency, besides a downscaled consumption of reagents and high rapidity for industrial-scale analysis of pharmaceutical preparations.

A comparative study of first-derivative spectrophotometry and high-performance liquid chromatography applied to the determination of losartan potassium in tablets

Losartan, a highly effective blood pressure-lowering agent, has been widely used for the treatment of hypertension. A fast and reliable method for the determination of losartan was highly desirable to support formulation screening and quality control. A first-derivative UV spectroscopic method and HPLC were developed for the determination of losartan in the tablet dosage form. The first-derivative spectrum recorded between 220 and 320 nm and a zero-crossing technique for first-derivative measurement at 232.5 nm were selected. The selectivity and sensitivity of the method was in desirable range. In comparison with the direct UV method, first-derivative UV spectroscopy has a definite trough without any interference from UV absorbing-excipients. This method is also fast and economical in comparison with the more time-consuming HPLC method regularly used for formulation screening and quality control and can be used routinely by any laboratory possessing a spectrophotometer with a derivative accessory. The linear concentration ranges were 2-50 microg ml(-1), (D(1)=-0.0159C-0.0056, r=0.9994, n=6). Between-days CV of < or =2.9%, within-day CV of < or =2.1%, and analytical recovery close to 98.1% show the suitability of the method for determination in quality control.

Behavior and quantification studies of amiloride drug using cyclic and square-wave adsorptive stripping voltammetry at a mercury electrode

The cyclic voltammograms of amiloride at the hanging mercury drop electrode showed a single well-defined four-electron irreversible cathodic peak in Britton-Robinson (B-R) buffer of pH 2. At higher pH values (pH > or =3), two irreversible cathodic peaks corresponding to the transfer of four (first peak) and two (second peak) electrons, were obtained The peak potentials were shifted to more negative values on the increase of pH of the medium, implying the involvement of protons in the electrode reaction and that the proton-transfer reaction precedes the proper electrode process. The 4-electron single peak (pH 2) or the first peak (pH > or = 3) may be attributed to the cleavage of the -CH=NH double bond of the N-imidino amide group with the release of NH(3) molecule. While the second peak may be due to the saturation of the C?O double bond of the carboxamide moiety. Based on the interfacial adsorptive character of the drug onto the mercury electrode surface, a simple, sensitive and low cost square-wave adsorptive cathodic stripping (SWAdCS) voltammetric procedure was optimized for analysis of the drug. The optimal operational conditions of the proposed procedure were: accumulation potential E(acc)= -0.7 V, accumulation time t(acc)= 60-65s, scan increment= 10 mV, pulse-amplitude = 50-60 mV, frequency =120 Hz using a B-R buffer of pH 8 as a supporting electrolyte. The linear concentration range was found to be 2 x 10(-9) to 2 x 10(-7) M amiloride with limits of detection (LOD) and quantitation (LOQ) of 1.9 x 10(-10) and 6.3 x 10(-10) M, respectively. The procedure was successfully applied for determination of amiloride in pharmaceutical formulation and spiked in human serum. The LOD and LOQ of amiloride spiked in human serum were 5.7 x 10(-10) and 1.9 x 10(-9) M amiloride, respectively. The procedure did not require sample pretreatment or any time-consuming extraction or evaporation steps, other than deproteinization and then centrifugal separation of protein from serum sample prior to analysis of the drug.