Combining benefits of an adrenergic and a muscarinic blocker in a single formulation – A pharmacokinetic evaluation

Micellar-enhanced and green-assessed first-derivative synchronous spectrofluorimetric approach for concurrent determination of alfuzosin hydrochloride and solifenacin succinate in different matrices: Docking simulation

Alfuzosin hydrochloride (AZH) is co-formulated with solifenacin succinate (SOS) in Solitral® capsules for treating prostate hyperplasia in patients with overactive bladder syndrome. Herein and for the first time, an ultrasensitive synchronous spectrofluorimetric approach coupled with first-order derivative signal processing was designed for simultaneous determination of AZH and SOS in their pure forms, newly-released pharmaceutical capsules, and human biological fluids. AZH and SOS showed their conventional emission spectra in bi-distilled water at 382 nm and 294 nm after excitation at 325 nm and 250 nm, respectively. The native fluorescence intensities of AZH and SOS were greatly enhanced through micellar formation using sodium dodecyl sulfate surfactant (2%). The proposed approach included the use of synchronous mode at Δλ of 60 nm where the overlap between the studied analytes' fluorescence spectra wasn't completely resolved. The complete resolution was achieved by derivatization of the synchronized spectra to the first-order yielding two zero-crossing points which allowed the determination of AZH and SOS simultaneously without interference at 408 nm and 321 nm, respectively. Under optimum experimental circumstances, good linearities were accomplished over the concentration ranges of (1-24) ng/mL and (4-250) ng/mL with LOD of 0.26 ng/mL and 1.31 ng/mL for AZH and SOS, respectively. The proposed approach was validated successfully according to guidelines adopted by the ICH and compared statistically with the reported LC method with no discernible differences concerning accuracy or precision at p = 0.05. Successful application of the proposed approach achieved with excellent recovery percentages for analysis of the studied analytes in different matrices (pharmaceutical capsules and biological fluids) confirms its suitability for use in QC laboratories and other bioanalytical applications. The proposed approach's greenness was evaluated using two tools namely; penalty points scoring system and green analytical procedure index (GAPI) divulging excellent greenness of this approach relative to the reported LC method. The proposed approach relied chiefly on water as the cheapest and greenest solvent.

Eco-friendly Spectrophotometric Methods for Assessment of Alfuzosin and Solifenacin in their new Pharmaceutical Formulation; Green Profile Evaluation via Eco-scale and GAPI Tools

Background:

Alfuzosin is recently co-formulated with solifenacin for relieving two coincident urological diseases, namely; benign prostate hyperplasia and overactive bladder.

Objective:

Herein, green, simple and rapid spectrophotometric methods were firstly developed for simultaneous determination of the two cited drugs in their co-formulated pharmaceutical capsule

Methods:

Alfuzosin, which is the major component in the dosage form, was directly assayed at its extended wavelength at 330.0 nm. The challenging spectrum of the minor component, solifenacin, was resolved by five spectrophotometric methods, namely; Dual Wavelength (DW) at 210.0 & 230.0 nm, first derivative (1D) at 222.0 nm, Ratio Difference (RD) at 217.0 - 271.0 nm, derivative ratio (1DD) at 223.0 and mean centering of ratio spectra (MC) at 217.0 nm.

Results:

The proposed methods were successfully validated as per ICH guidelines. Alfuzosin showed linearity over the range of 4.0 - 70.0 μg/mL, while that of solifenacin were 4.0 - 50.0 μg/mL for DW, 2.0 - 70.0 μg/mL for 1D and RD methods, 1.0 - 70.0 μg/mL for 1DD and 4.0 - 70.0 μg/mL for MC method. Statistical comparison with their official ones showed no noticeable differences. The methods showed good applicability for assaying drugs in their newly combination. Besides the eco-scale, the greenness profile of the methods was assessed and compared with the reported spectrophotometric one via the newest metric tool; Green Analytical Procedure Index (GAPI).

Conclusions:

The proposed methods are superior in not only being smart, accurate, selective, robust and time-saving, but also in using distilled water as an eco-friendly and cheap solvent.

Evaluation and clinical comparison studies on liposomal and non-liposomal ascorbic acid (vitamin C) and their enhanced bioavailability

The aim of this study was to evaluate the oral bioavailability of liposomal vitamin C and non-liposomal vitamin C in healthy, adult, human subjects under fasting conditions through an open label, randomized, single-dose, two-treatment, two-sequence, two-period, two-way crossover, study. The vitamin C loaded liposome was well characterized using transmission electron microscopy (TEM), dynamic light scattering (DLS) and zeta potential measurements for evaluating morphology, particle size and stabilities, respectively. Microscopic image shows the core-type structure that confirms the characteristic pattern of liposome. The encapsulation efficiency (EE%) and the particle size were 65.85 ± 1.84% and below 100 nm, respectively. The results of the clinical studies of liposomal vitamin C by oral delivery to be 1.77 times more bioavailable than non-liposomal vitamin C. The liposomal vitamin C demonstrated higher values of C_max, AUC_0-t and AUC_0-∞ related to non-liposomal vitamin C due to liposomal encapsulation. No adverse events were reported. It could be concluded that liposomal encapsulated ascorbic acid (vitamin C) shows well-organized morphological pattern, uniform particle size and highly efficient, which leads to have enhanced bioavailability.

Pharmacokinetics and Bioequivalence Estimation of Two Formulations of Alfuzosin Extended-Release Tablets

Alfuzosin is a medication approved by the US Food and Drug Administration to treat benign prostatic hyperplasia symptoms. Bioequivalence studies are demanded by regulatory authorities to evaluate the expected in vivo biological similarity of 2 formulations of a medication. The aim of this study is to assess the bioavailability of the generic (test) and branded (reference) formulations of 10-mg alfuzosin extended-release tablets after oral administration to healthy adults under fed conditions. The study used a comparative randomized, single-dose, 2-way crossover open-label study design. Thirty-three participants were recruited and completed the clinical assessment. The pharmacokinetic parameters maximum plasma concentration (C_max ), area under the plasma concentration-time curve (AUC_0-t ), AUC extrapolated to infinity (AUC_0-∞ ), time to maximum concentration, and elimination half-life were estimated to prove bioequivalence. The confidence intervals for the log-transformed test/reference ratios for alfuzosin 110.7% (98.0-124.9) and 112.0% (101.9-123.1) for C_max and AUC_0-t respectively, which are within the allowed limits specified by the regulatory authorities (80-125% for C_max and AUC_0-t ). The test formulation can therefore be prescribed as an alternative to the reference for symptomatic treatment of benign prostatic hyperplasia.

A novel HPLC-DAD method for simultaneous determination of alfuzosin and solifenacin along with their official impurities induced via a stress stability study; investigation of their degradation kinetics

Stability and impurity profiling are in high demand to guarantee the potency, safety and efficacy of new formulations along with their shelf-life. In this study, stability testing of alfuzosin (ALF) and solifenacin (SOL) in their newly co-formulated capsules was conducted under different stress conditions. The obtained degradation products were structurally elucidated and found to be their official impurities, namely; ALF impurity-D and SOL impurities-A, E & I. A selective and reliable stability-indicating HPLC method was developed for assaying the cited drugs along with three of those official impurities. Chromatographic separation was accomplished within 8 minutes using a XBridge® C18 column as the stationary phase and acetonitrile : phosphate buffer (pH 8) : triethylamine (60 : 40 : 0.02, by volume) as the mobile phase at a flow rate of 1.3 mL min-1. Quantification of the analytes was performed at 210 nm using a diode array detector through which peak purity was assessed. The proposed method was validated as per ICH guidelines and it was successfully applied for the determination of the cited drugs in their combined pharmaceutical formulation with percent recoveries of 100.47 and 100.15 for ALF and SOL, respectively. Moreover, the proposed method was exploited for the assessment of the two drugs' stability in Solitral® capsules under accelerated storage conditions. The method was further extended for studying the degradation kinetics of the two drugs.

Pharmacokinetics comparison of solifenacin tartrate and solifenacin succinate: a randomized, open-label, single-dose, 2-way crossover study in healthy male volunteers

Solifenacin is a muscarinic antagonist indicated for the treatment of overactive bladder with symptoms. Solifenacin tartrate is a newly developed salt formulation of solifenacin. This study compared the pharmacokinetic and safety properties after single-dose administration of solifenacin tartrate (test formulation) and solifenacin succinate (reference formulation) in healthy male volunteers. A total of 36 subjects were enrolled in this randomized, open-label, single-dose, two-way crossover study. During each treatment period, subjects received the test formulation or reference formulation. Plasma samples were collected at pre-dose and at 1, 2, 3, 4, 5, 6, 7, 8, 10, 12, 24, 48 and 72 hours post-dose. Safety was assessed by adverse events, physical examinations, laboratory assessments, 12-lead electrocardiograms, and vital signs. Thirty-three subjects completed the study and were included in the pharmacokinetic analysis. The mean (standard deviation) values of AUC_last for the test and reference formulations were 486.98 (138.47) and 469.07 (128.29) h·ng/mL, respectively. The mean (standard deviation) values of C_max for the test and reference formulations were 14.66 (3.85) and 14.10 (3.37) ng/mL, respectively. The 90% confidence intervals for AUC_last and C_max were 0.9702 to 1.1097 and 0.9779 to 1.0993, respectively. All adverse events were mild or moderate, and there were no serious adverse events. The pharmacokinetic properties of solifenacin tartrate were similar to those of solifenacin succinate and met the acceptance criteria for bioequivalence. Both formulations were safe, and no significant difference was observed in the safety assessments of the formulations.

Population Pharmacokinetics of Fixed Dose Combination of Ceftriaxone and Sulbactam in Healthy and Infected Subjects

Increased antibacterial resistance (ABR) and limited drug discovery warrant optimized use of available antibiotics. One option is to rationally combine two antibiotics (fixed dose combination (FDC)) that may delay or prevent emergence of ABR in notorious pathogen. Major concern with FDC is the mutual interaction of its components that might influence their pharmacokinetic (PK) profile, requiring reassessing of whole formulation (adding cost and time). The interaction can be identified by comparing PK profile of a drug present in FDC with its independent entity. An open-label, crossover, single-dose comparative PK study of FDC (ceftriaxone and sulbactam) with their individual reference formulations was performed in 24 healthy adult subjects. No mutual PK interactions between ceftriaxone and sulbactam were observed. Pharmacokinetic data was used to develop a population-PK model to understand between-subject variability (BSV). Pharmacokinetics of ceftriaxone/sulbactam was explained by one and two compartment models, respectively. The subject's "weight" was identified as a covariate explaining BSV. Both internal and external validations (healthy/infected subjects) were done. The model-derived population-PK parameters of FDC's active components in infected subjects were similar to literature reported values of individual components. Efficacies of various FDC dosage regimens over a range of minimum inhibitory concentrations (MICs) were assessed by Monte Carlo simulations using population-PK parameters of infected/healthy subjects. In infected subjects, 3 g FDC/24 h can treat bacteria with MIC ≤8 μg/mL, while for MIC 8-32 μg/mL, 3 g FDC/12 h is recommended. Lastly, the developed population-PK model was successfully used to predict drug exposure in pediatric population.