An eco- friendly, selective, and sensitive spectrofluorimetric method for the quantification of Dolutegravir in its bulk and tablet dosage form.

This study is concerned with assessing the bulk and tablet dosage forms of Dolutegravir (DTG) by means of a novel yet simple environmentally friendly spectrofluorimetric method that features fast response and high sensitivity compared to the time consuming HPLC methods and the lower sensitivity spectrophotometric ones. The method relies mainly on measuring the native fluorescence of Dolutegravir in water at an emission of 415 nm after excitation at 262 nm. The method shows rectilinear fluorescence-concentration relation over Dolutegravir concentration range of 0.2-1.2 µg/mL at the emission maxima, with detection limit of 0.020 µg/mL and quantification limit of 0.061 µg/mL. The results of the proposed method were compared with those obtained by applying the comparison method and the two sets coincided harmoniously. In addition, the method was validated in accordance with ICH guidelines for linearity, accuracy, precision, specificity, and robustness.

Simultaneous determination of naltrexone and bupropion in their co-formulated tablet utilizing green chromatographic approach with application to human urine.

A rapid, simple and accurate micellar HPLC-method was adopted and validated for concurrent quantification of naltrexone hydrochloride (NTX) and bupropion hydrochloride (BUP). The proposed method was conducted on RP-18 LiChrosorb® column (150 mm × 4.6 mm i.d. 5-µm particle size) at 25 °C, as a stationary phase and a mixture of 0.175 M sodium dodecyl sulphate (SDS), 0.3% triethanolamine (TEA) and 12% n-propanol in 0.02 M ortho (o)-phosphoric acid of pH 3.5 as a developing system. It was pumped at a flow rate of 1.2 mL/min, with ultraviolet detection at 210 nm. The linearity ranges were 0.5-15.0 µg/mL and 1.2-18.0 µg/mL, with detection limits of 0.10 and 0.31 µg/mL and quantification limits of 0.30 and 0.93 µg/mL for NTX and BUP, respectively. The studied drugs were successfully quantified by applying the proposed method in their co-formulated tablet. The cited method was also applied for in-vitro quantification of BUP in spiked human urine without prior extraction.

Selective and sensitive spectrofluorimetric quantification of velpatasvir in presence of sofosbuvir. Application to their co-formulated tablet.

A new sensitive, rapid and simple spectrofluorimetric method was utilized for the assessment of velpatasvir (VPS) in its bulk form as well as in its combined tablet with sofosbovir (SFV). The technique relies on measuring the native fluorescence of VPS in methanol at 385 nm and 400 nm after excitation at 295 nm. The fluorescence-concentration plots were rectilinear through the range of 2.0-20.0 ng mL-1 at both emission maxima with lower detection limits of 0.146 ng mL-1 and 0.378 ng mL-1, and lower quantification limits of 0.444 ng mL-1 and 1.147 ng mL-1 at 385 nm and 400 nm, respectively. The proposed method was appropriately used for the analysis of VPS in its commercial tablet formulation and the results were in good agreement with those achieved with the applied comparison method.

Validated stability-indicating liquid chromatographic method for the determination of ribavirin in the presence of its degradation products: application to degradation kinetics.

Ribavirin was found to be liable to acidic, alkaline, oxidative and photolytic degradation. Hence, a simple, sensitive and stability-indicating reversed-phase liquid chromatographic method was developed and validated for the determination of ribavirin in the presence of its degradation products. The analysis was carried out on an ODS C18 (250 × 4.6 mm i.d.) stainless steel column using a mobile phase consisting of 0.02 M potassium dihydrogen phosphate. The analysis was performed at ambient temperature with a flow rate of 1 mL/min and UV detection at 207 nm. Pyridoxine hydrochloride was used as an internal standard. The method showed good linearity over the concentration range of 2.0-40 µg/mL with limit of detection of 0.34 µg/mL and limit of quantification of 1.03 µg/mL. The suggested method was successfully applied for the analysis of ribavirin in its commercial capsules. Statistical evaluation and comparison of the data obtained by the proposed and comparison method revealed good accuracy and precision of the proposed method. The drug was exposed to forced alkaline, acidic, oxidative and photolytic degradation according to the ICH guidelines. Moreover, the method was utilized to investigate the kinetics of alkaline and acidic degradation of the drug. The apparent first-order rate constants, half-life times and activation energies of the degradation process were calculated.

Stability-indicating polarographic determination of acyclovir through chelation with nickel(II).

A simple and sensitive, stability-indicating polarographic method was developed for the determination of acyclovir (ACV) in raw materials and dosage forms. The proposed method relies on the chelation of ACV with nickel(II) in Britton Robinson buffer (pH 5) and measuring the resulting polarographic wave either in the direct current (DCt) or differential pulse (DPP) modes. The polarographic wave has been characterized as being catalytic reduction prewave. Different experimental parameters affecting the formation of the Ni-ACV chelate and its polarographic activity were studied and optimized. The current concentration relationship was found to be linear over the range of 0.8-8 and 1-8 microg/mL, with minimum detectabilities of 0.10 and 0.19 microg/mL using DPP and DCt modes, respectively. The method was used to investigate the kinetics of the acid-induced degradation of the drug. The apparent first-order rate constants and half-life times were calculated.