Novel spectrophotometric and factor-based multivariate calibration-prediction techniques for determination of two inhibitors of hepatitis C-virus and hepatocellular carcinoma in pure, human urine, and human plasma.

Novel univariate and multivariate factor-based calibration-prediction techniques were validated for simultaneous ultraviolet spectrophotometric determination of ribavirin (RIV), daclatasvir (DAV), sofosbuvir (SOV), and sorafenib (SON) which are co-administered for treatment of hepatocellular carcinoma (HCC) that results from Hepatitis C-virus (HCV) infection in their commercial products and in biological fluids. Determination of these compounds is essential owing to their pharmacotherapeutic benefits. Due to spectral overlapping of RIV, DAV, SOV, and SON, univariate extended derivative ratio (EDR) method and multivariate partial least-squares (PLS) and principal component regression (PCR) methods were used for constructing the calibration curves. The extended derivative ratio (EDR) absorption maxima at 215 nm and minima at 310.5 nm was used for determination of RIV and DAV, respectively and absorption maxima at 240.3 nm and minima at 284.5 nm for determination of SOV and SON, respectively. The linearity was established over the range of 6-42 µg mL-1, 4-16 µg mL-1, 10-70 µg mL-1, and 3-9 µg mL-1 for RIV, DAV, SOV and SON with correlation coefficient (r2) of 0.9997, 0.9997, 0.9999 and 0.9997, respectively. This method was effectively applied to pure, pharmaceutical preparations and to spiked human urine and plasma. PLS and PCR models were established for the determination of the studied drugs in the range of 6-42, 4-16, 10-70 and 3-9 µg mL-1 for RIV, DAV, SOV, and SON, respectively. Furthermore, updating the PLS model (PLS model update) were allowed for the determination of these drugs in spiked human urine, plasma and drug-dissolution test of their tablets. The obtained results were compared to official and reported method showing that there were no significant differences. The results of applying PLS and PCR models for evaluation of RIV, DAV, SOV, and SON in human urine samples as real samples were also encouraging. It is expected that the suitable features of the proposed method make it helpful for biological and clinical applications.

Investigation of anti-Hepatitis C virus, sofosbuvir and daclatasvir, in pure form, human plasma and human urine using micellar monolithic HPLC-UV method and application to pharmacokinetic study.

Simultaneous determination of sofosbuvir (SOF), and daclatasvir (DAC) in their dosage forms, human urine and human plasma using simple and rapid micellar high performance liquid chromatographic method coupled with UV detection (HPLC-UV) had been developed and validated. These drugs are described as co-administered for treatment of Hepatitis C virus (HCV). HCV is the cause of Hepatitis C and some cancers such as liver cancer (hepatocellular carcinoma) and lymphomas in humans. Separation and quantitation were carried out on anonyx™ C8 monolithic (100 × 4.6 mm (i.d.) analytical column maintained at 25 °C. The mobile phase consisted of 0.1 M sodium dodecyl sulfate (SDS) solution containing 20% (V/V) n-propanolol and 0.3% (V/V) triethylamine and pH was adjusted to 6.5 using 0.02 M phosphoric acid, respectively. The retention times of SOF and DAC were 4.8 min, and 6.5 min, respectively. Measurements were made at flow rate of 0.5 mL/min with injection volume of 20 µL and ultraviolet (UV) detection at 226 nm. Linearity of SOF and DAC was obtained over concentration ranges of 50-400, and 40-400 ng/mL, respectively in pure form, 60-300 and 50-300 ng/mL, respectively for human plasma and over 50-400, and 40-400 ng/mL, respectively for human urine with correlation coefficient >0.999. The proposed method demonstrated excellent intra- and inter-day precision and accuracy. The suggested method was applied for determination of the drugs in pure, dosage form, and in real human plasma, real human urine and drug-dissolution test of their tablets. The obtained results have been statistically compared to reported method to give a conclusion that there is no significant differences.

Utility of Cremophor RH 40 as a micellar improvement for spectrofluorimetric estimation of sorafenib in pure form, commercial preparation, and human plasma.

An easy, quick, simple and accurate spectrofluorimetric method was recognized and validated for evaluation of sorafenib (SOR) in pure form and biologically in plasma. Cremophor RH 40 (Cr RH 40) used for enhancing the fluorescence activity of SOR in phosphate buffer (pH 7). Cr RH 40 improved the native fluorescence of SOR remarkably in water. The fluorescence spectrum of SOR was observed at 405 nm after excitation at 265 nm. The linearity appeared to be in the range of 5 to 600 ng ml-1 for pure and from 9 to 500 ng ml-1 for plasma using the protein precipitation (ppt) method while from 10 to 500 ng ml-1 for plasma using liquid-liquid extraction method. The precisions and the accuracy of the estimated method gave satisfactory results. The recommended method was effectively applied for determination of SOR in human plasma with high recovery values. The results of some compounds that are possibly found in plasma were studied. The proposed method was also focused on real volunteers and a drug dissolution test.

A novel spectrofluorimetric method for determination of imatinib in pure, pharmaceutical preparation, human plasma, and human urine.

The following paper represents a simple, highly sensitive, responsive validated and developed spectrofluorimetric method for estimation of imatinib (IMB) in its pure, commercial preparation, human urine and human blood plasma. The calibration curve was in the range 4-900 ng ml-1 for pure form and urine and 8-900 ng ml-1 for plasma in a medium contains carboxymethyl cellulose (CMC) and acetate buffer (pH 5) with excitation wavelength (λex ) 230 nm and emission wavelength (λem ) 307 nm. The limit of detection (LOD) was 0.37 ng ml-1 for the pure form, 0.64 ng ml-1 for human urine, and 0.70 ng ml-1 for human plasma, while the limit of quantitation (LOQ) was 1.2 for pure form, 1.91 for urine and 2.1 for plasma. The suggested method was successfully applied for evaluation of IMB in tablets within 99% mean percentage recovery. The excipients that are usually used as additives in pharmaceutical dosage form did not interfere with the suggested method. The method was efficiently used for estimation of IMB in human urine and human plasma. The effect of some cations that might be present in urine and plasma was also studied. The method was also focused on human volunteers and in vitro drug release.

Spectrophotometric and AAS determination of ramipril and enalapril through ternary complex formation.

Two sensitive, spectrophotometric and atomic absorption spectrometric procedures are developed for the determination of two antihypertensive agents (enalapril maleate and ramipril). The spectrophotometric procedures for the two cited drugs are based on ternary complex formation. The first ternary complex (copper(II), eosin, and enalapril) was estimated by two methods; the first depends on its extraction with chloroform measuring at 533.4 nm. Beer's law was obeyed in concentration range from 56 to 112 microg ml(-1). The second method for the same complex depends on its direct measurement after addition of methylcellulose as surfactant at the pH value 5 at 558.8 nm. The concentration range is from 19 to 32 microg ml(-1). The second ternary complex (iron(III), thiocyanate, and ramipril) was extracted with methylene chloride, measuring at 436.6 nm, with a concentration range 60-132 microg ml(-1). The direct atomic absorption spectrometric method through the quantitative determination of copper or iron content of the complex was also investigated for the purpose of enhancing the sensitivity of the determination. The spectrophotometric and atomic absorption spectrometric procedures hold their accuracy and precision well when applied to the determination of ramipril and enalapril dosage forms.