Drug In Aqueous Solution Research Articles

Neomycin Intercalation in Montmorillonite: The Role of Ion Exchange Capacity and Process Conditions.

The study examined the possibility of intercalation of montmorillonite with neomycin in an aqueous drug solution and the factors influencing the effectiveness of this process, such as the ion exchange capacity and process conditions, including the time and temperature of incubation with the drug. X-ray diffractometry (XRD), infrared spectroscopy (FTIR), thermal analysis (DSC/TG), and Zeta potential measurement were used to confirm drug intercalation as well as to investigate the nature of clay-drug interactions. The obtained conjugates with the most favorable physicochemical properties were also tested for antibacterial response against Gram-negative bacteria (Escherichia coli) to confirm that the bactericidal properties of neomycin were retained after intercalation and UV-VIS spectrophotometry was used to examine the kinetics of drug release from the carrier. The results of the conducted research clearly indicate the successful intercalation of neomycin in montmorillonite and indicate the influence of process parameters on the properties of not only the conjugates themselves but also the properties of the intercalated drug, particularly its bactericidal activity. Ultimately, a temperature of 50 °C was found to be optimal for effective drug intercalation and the conjugates obtained within 2 h showed the highest antibacterial activity, indicating the highest potential of the thus-obtained montmorillonite conjugates as neomycin carriers.

Association and clouding behaviour of surfactants in aqueous solution of propranolol hydrochloride drug: Understanding of the effects of potassium salts and temperatures

The investigation of the assembly of lithium dodecyl sulfate (LDS) and cloudy creation of triton X-100 (TX-100) in aqueous solution of amphiphilic drug propranolol hydrochloride (PLH) has been carried out by electrical conductivity and cloud point estimation method respectively. The influences of three potassium electrolytes (KCl, K2SO4, and K3PO4) on the micellization of LDS and clouding of TX-100 in presence of PLH drug have been examined. The conductivity experiments were conducted at temperatures between 288.15 and 323.15 K, with a 5 K interval.The introduction of PLH drug promotes the micelle formation of LDS up to 1 mmol kg−1 of drug. The critical micelle concentration (CMC) values of LDS in aqueous solution of PLH were shifted to lower values in aqueous electrolytes media. The cloud point (CP) of TX-100 + PLH system was observed to be increased with the rise in concentrations of PLH in aqueous medium. The reduction in the CP values of TX-100 and PLH mixed system has been attained with the enrichment of the concentrations of electrolytes and at a specific mole fraction of electrolytes, the CP values exhibited the order: CP (KCl (aq.)) > CP (K2SO4 (aq.)) > CP (K3PO4 (aq.)). The Gibbs free energy of assembly (ΔGm0) appeared as negative (spontaneous assembly) whereas ΔGc0 of clouding showed positive magnitudes indicating the nonspontaneous nature of the clouding process. The micellization of LDS demonstrate the endothermic and exothermic nature at lower and higher investigated temperature as revealed from the sign of ΔHm0values.. The positive values of entrpoyΔSm0 exhibit the micellization process to be entropically driven phenomena. The phase separation of TX-100 and PLH mixed system is entropy contributed in aqueous medium while the clouding in the presence of salts is enthalpy contributed evidenced from the negative enthalpy of clouding.

In-situ forming Cu-based metal-organic framework in the presence of chitosan-Fe3O4 nanohybrids: A pH-sensitive carrier for controlled release of doxorubicin

In recent years, stimuli-responsive drug delivery systems based on pH, particularly those developed using bio-derived nanocomposite systems, have gained significant attention. In this work, a novel magnetic carrier was designed based on biopolymeric chitosan and metal-organic framework (MOF) for pH-controlling the release of anticancer drugs. To end this, an in-situ green method was performed to form Cu-based MOF in the presence of a magnetic polysaccharide synthesized by precipitation method toward the construction of CS/Fe3O4/Cu-MOF nanocomposite. The nanocomposite was immersed in an aqueous solution of a model anticancer drug, doxorubicin (DOX), and a higher loading capacity (90.1 ± 0.5 %) was achieved. The in-vitro drug release study showed low release rates in simulated physiological environments (pH 7.4, 37 °C, lower than about 20 %), but higher release rates in tumor tissue conditions (pH 4.5, 41 °C, higher than about 60 %) over 96 h, allowing for sustained and extended delivery of DOX. Additionally, the MTT assay demonstrated that the blank and DOX-loaded CS/Fe3O4/Cu-MOF had good cytocompatibility (over 80 % cell viability) and considerable cytotoxicity (lower than 40 % at 16 μg/mL) toward breast cancer (MCF-7) cell line, respectively. These results indicated that the synthesized nanocomposite with suitable pH-sensitivity has potential as a targeted anticancer agent.

Thermo and pH-responsive nanocarriers based on mesocellular silica foam and poly(N-vinylcaprolactam-co-methacrylic acid): Synthesis, characterization, and in vitro cytotoxicity assay

Smart hybrid nanocarriers were prepared by grafting poly(N-vinylcaprolactam-co-methacrylic acid) (poly(NVCL-co-MAA)) onto mesocellular silica foams (MCF silica) to evaluate them as controlled delivery systems of doxorubicin (DOX). The development of these nanocarriers began with the synthesis of MCF silica with interconnected porous structures and an average pore diameter of 27 nm. Then, free radical polymerization was used to graft the smart copolymer, and some parameters such as comonomer concentration and reaction time were studied. The DOX was loaded by immersion in an aqueous drug solution, while the in vitro release was investigated at different pHs (7.4, 5.8) and temperatures (25, 37 °C). In addition, the cytotoxicity of nanocarriers was investigated in vitro using the direct contact method with human breast cancer cells (SKBR3). In general, hybrid nanocarriers with copolymer graft percentages ranging from 30 to 60 % were obtained. On the other hand, at higher grafting of poly(NVCL-co-MAA) onto MCF silica, higher drug loading (up to 6.41 × 10−2 mg DOX/mg HN) was observed. Furthermore, in vitro DOX release results suggested that the nanocarriers released up to 52 % at 37 °C and a pH of 5.8. Finally, the in vitro cytotoxicity assay revealed that the DOX-loaded hybrid nanocarriers were cytotoxic to SKBR3 cells, indicating a controlled administration of DOX from the nanocarriers compared to free DOX. These results suggest that nanocarriers could have great potential for use as controlled delivery systems of anticancer drugs.

Dough-Kneading-Inspired Design of an Adhesive Cardiac Patch to Attenuate Cardiac Fibrosis and Improve Cardiac Function via Regulating Glycometabolism.

Recently, hydrogel adhesive patches have been explored for treating myocardial infarction. However, achieving secure adhesion onto the wet beating heart and local regulation of pathological microenvironment remains challenging. Herein, a dough-kneading-inspired design of hydrogel adhesive cardiac patch is reported, aiming to improve the strength of prevalent powder-formed patch and retain wet adhesion. In mimicking the polysaccharide and protein components of natural flour, methacrylated polyglutamic acid (PGAMA) is electrostatically interacted with hydroxypropyl chitosan (HPCS) to form PGAMA/HPCS coacervate hydrogel. The PGAMA/HPCS hydrogel is freeze-dried and ground into powders, which are further rehydrated with two aqueous solutions of functional drug, 3-acrylamido phenylboronic acid (APBA)/rutin (Rt) complexes for protecting the myocardium from advanced glycation end product (AGEs) injury by reactive oxygen species (ROS) -responsive Rt release, and hypoxanthine-loaded methacrylated hyaluronic acid (HAMA) nanogels for enhancing macrophage targeting ability to regulate glycometabolism for combating inflammation. The rehydrated powders bearing APBA/Rt complexes and HAMA-hypoxanthine nanogels are repeatedly kneaded into a dough-like gel, which is further subjected to thermal-initiated crosslinking to form a stabilized and sticky patch. This biofunctional patch is applied onto the rats' infarcted myocardium, and the outcomes at 28 days post-surgery indicate efficient restoration of cardiac functions and attenuation of cardiac fibrosis.

Interaction of sodium dodecyl sulfate and cetyl trimethyl ammonium bromide surfactants with amantadine drug in aqueous solution: Conductometric and molecular dynamics studies

In the present work, the interaction of sodium dodecyl sulfate and cetyl trimethyl ammonium bromide surfactants with amantadine drug in aqueous solutions was studied using conductometric measurements and molecular dynamic simulation. Conductometric data were used to determine the critical micelle concentration (CMC) values of surfactants on various amantadine aqueous solutions at T= (300.2, 310.2 and 320.2) K and 0.1 MPa. The effect of amantadine concentration (m = 0.0005, 0.0010, 0.0015 and 0.002 mol.kg−1) on CMC of sodium dodecyl sulfate and cetyl trimethyl ammonium bromide surfactants was investigated. It was observed the CMC value of sodium dodecyl sulfate surfactant increases with increasing of amantadine concentration whereas the CMC values of cetyl trimethyl ammonium bromide surfactant decrease with increasing of amantadine concentration at the same temperature. Then, the thermodynamic properties such as standard Gibbs free energy, enthalpy, and entropy for micellization in aqueous solutions were determined. In addition, molecular dynamic simulation was carried out to understand the interaction sodium dodecyl sulfate and cetyl trimethyl ammonium bromide surfactants with amantadine at the molecular level and microscopic interactions. The root-mean-square deviations and electrostatic, hydrogen binding and hydrophobic interactions were determined by MD simulations. It was seen, the electrostatic and hydrogen bonding interactions play a crucial role in sodium dodecyl sulfate and amantadine aqueous system. The obtained results showed the simulation and experimental data are in agreement with each other.

Important role of pore-filling mechanism in separating naproxen from water by micro-mesoporous carbonaceous material.

Commercial micro-mesoporous carbonaceous material (MCM; 56.8% mesopores) was applied for investigating the removal phenomenon of naproxen drug in aqueous solutions through batch adsorption experiments. Results demonstrated that the adsorption capacity of MCM to naproxen was slightly affected by different pHeq (2.0-11) and ionic strength (0-1M NaCl). Adsorption kinetics, isotherms, thermodynamics, and mechanisms were evaluated at pH7.0. Adsorption kinetics indicated the rate constants for adsorption (0.2 × 10-3 L/(mg × min) and desorption (0.076/min) and the adsorption equilibrium constant (2.6 × 10-3 L/mg). Adsorption isotherm showed that MCM exhibited a high-affinity adsorption capacity to naproxen (even at low concentrations) and its Langmuir maximum adsorption capacity (Qmax ) was 252.7mg/g at 25°C. Adsorption thermodynamics proved that the adsorption process was endothermic and physisorption (ΔH° = 9.66 kJ/mol). The analysis result of pore size distribution demonstrated that the internal pore structure of MCM was appropriate for adsorbing naproxen molecules. Pore-filing mechanism (pore diffusion phenomenon) was confirmed by a considerable decrease in BET-surface area (585 m2 /g) and total pore volume (0.417 cm3 /g) of MCM after adsorbing naproxen (~1000 mg/L and pH7.0) at 5min (341 and 0.256), 60 min (191 and 0.205), 120 min (183 and 0.193), 360 min (144 and 0.175), and 24 h (71.6m2 /g and 0.123 cm3 /g, respectively). The pore diffusion occurred rapidly (even at the initial adsorption period of 5min). The FTIR technique was applied to identify the existence of C-H···π and n-π interaction. π-π interaction (evaluated through ID /IG ratio and C=C band) played a minor contribution in adsorption mechanisms. The ID /IG ratio (determined by the Raman technique) of MCM before adsorption (1.195) was similar to that after adsorption (1.190), and the wavenumber (C=C band; its FTIR spectrum) slightly shifted from 1638 to 1634 cm-1 after adsorption. A decrease in the Qmax value of MCM from 249 to 217 (H2 O2 -oxidized MCM) or to 224 mg/g (HNO3 -oxidized MCM) confirmed the presence ofπ-π interaction. Electrostatic attraction was a minor contribution. MCM can serve as a promising material for removing naproxen from water environment through a pore-filling mechanism. PRACTITIONER POINTS: Pore-filling mechanism was proposed by comparing textural properties of MCM before and after adsorbing naproxen. C-H···π and n-π interactions were identified via FTIR technique. π-π interaction was observed by FTIR and Raman techniques. Oxidation of MCM with HNO3 or H2 O2 was a helpful method to explore π-π interaction. Electrostatic attraction was explained through studies: effects of pH and NaCl along with desorption.

Structural flexibility of favipiravir and its structural analogues in solutions: experimental and computational insight.

Combined UV-vis and quantum chemical studies of the structural flexibility and tautomerism of 6-R-3-hydroxy-2-pyrazine carboxamides in solutions revealed that their keto-enol transformations are accompanied by the deprotonation of enol tautomers and the formation of the corresponding anionic species. Both the solvent and the 6-R substituent strongly influence the relative abundance of the above forms in solutions. Anions are not formed in 1,2-dichloroethane (DCE), but the probability of deprotonation in neutral water and N,N-dimethylformamide (DMF) increases in the order R = H < F < NO2. Only enol tautomers of all solutes are found in DCE. DMF stabilizes keto forms only moderately and assists much strongly in the deprotonation of all three compounds. Water tends to stabilize both keto tautomers and deprotonated anions: the keto form dominates in the case of R = H (antiviral drug T-1105), the anions are found exclusively for R = NO2, and the aqueous solution of another antiviral drug, favipiravir (R = F), contains both the keto tautomer and the anionic form. The results of quantum chemical free energy calculations are in agreement with the experimental observations.

The Effect of High-Pressure Homogenization Conditions on the Physicochemical Properties and Stability of Designed Fluconazole-Loaded Ocular Nanoemulsions.

The growing interest in high-energy emulsification is a result of its scalability, which is important from an industrial perspective and allows for a more reproducible and efficient production of pharmaceutical formulations. The aim of this study was to evaluate the effect of composition, mainly a fixed surfactant/cosurfactant (Smix) ratio, their concentration, and the parameters of high-pressure homogenization (HPH) processing on the quality and stability of ophthalmic fluconazole-loaded nanoemulsions. After a physicochemical analysis of nanoemulsions containing 20% w/w of oil, as optimal conditions for the HPH process, three cycles at a pressure of 1000 bar were established, obtaining formulations with an average droplet diameter size in the range of 80.63-129.68 nm and PDI values below 0.25. While it was expected that an increasing cosurfactant concentration decreased the droplet size, in the case of formulations containing Tween 20 and 10% w/w of cosurfactants, "over-processing" was observed, identified by the droplet size and polydispersity index increase. Consecutively, the selected formulations were evaluated for in vitro drug release in Franz's cell, antifungal activity, and 30-day stability using NMR spectroscopy. An antifungal activity test showed no significant difference in the antifungal activity between optimal fluconazole-loaded nanoemulsions and a 0.3% aqueous drug solution, but previously, research showed that prepared formulations were characterized by a higher viscosity and satisfactory prolonged release compared to a control. In a 30-day stability study, it was observed that higher HLB values of the used surfactants decreased the stability of the formulations in the following order: Kolliphor EL, Tween 80, Tween 20. The NMR spectra confirmed that Kolliphor EL-based formulations ensured the higher stability of the nanoemulsion composition in comparison to Tween 80 and a better stabilizing effect of propylene glycol as a cosurfactant in comparison to PEG 200. Therefore, the optimization of HPH technology should be focused on the selection of Smix and the Smix:oil ratio in order to prepare stable formulations of high quality.

Investigation of intermolecular interactions of l-Valine and l-Phenylalanine with muscle relaxant drug mephenesin molecule prevalent in aqueous solution by various physico-chemical methods at T=298.15K–313.15K

A complete chemical analysis of significant intermolecular interactions of l-Valine (L-Val) and l-Phenylalanine (L-Phe) with Mephenesin (MEPN) molecules in aqueous solution has been studied by different physicochemical methodologies at various temperatures (T = 298.15 K–313.15 K at an interval of 5 K) and concentrations (0.001 mol kg−1, 0.003 mol kg−1, 0.005 mol kg−1) of aqueous MEPN solution. The limiting apparent molar volume (φV0) and experimental slope (SV*) values are found from the equation of Masson, viscosity A and B-coefficient determined using the equation of Jones-Doles, molar refraction (RM) and limiting molar refraction (RM0) derived by the Lorentz-Lorenz equation, express that in our experimental solution of amino acids (AAs) in aqueous MEPN, the solute-solvent interaction predominates over the solute-solute and solvent-solvent interactions for these ternary solutions. These are also justified by the measurement of various thermodynamic parameters, free energy of activation of viscous flow per mole of solvent(Δμ1°#) and solute (Δμ2°#), activation of viscous flow of enthalpies (ΔH°#) and entropies (ΔS°#). The characteristics of structure-breaking of solutes in the aqueous drug solution have been identified by Hepler's method and dB/dT value. The spectroscopic methods like UV–visible and proton-NMR studies help to explicate the strong AA-MEPN interactions in the solution phase and obtain a good correlation with theoretical studies. Theoretical investigations are checked to authenticate the experimental observations and according to both studies, L-Phe-MEPN interaction is greater than L-Val-MEPN interaction. The experimental and correlated research data are useful for the development of model combinations of AAs with drug molecules in pharmaceutical and medicinal chemistry.

Preparation of Tamsulosin Hydrochloride-Loaded Mucoadhesive In Situ Gelling Polymeric Formulation for Nasal Delivery in Geriatrics.

This study aimed to prepare tamsulosin hydrochloride (HCl)-loaded in situ gelling formulation by using hydroxypropyl methylcellulose (HPMC), gellan gum, poloxamer 188, and benzalkonium chloride. Physicochemical evaluation of formulations included determination of pH, viscosity, gelation time, gel strength, drug content, and sterility. In silico study was performed to analyze interactions between polymers, drug, and mucin glycoprotein. In vitro degradation time, drug release, ex vivo mucoadhesion time, permeation, in vivo pharmacokinetics, and stability studies were performed to assess the formulation. Formulations were transparent and displayed acceptable physicochemical attributes. Tamsulosin HCl and polymers interacted via non-covalent interactions. HPMC formed hydrogen bonds, hydrophobic and van der Waals interactions with mucin protein while the drug formed hydrogen bonds only. Gel formulation degraded in simulated nasal fluid within 24 h. In situ gelling formulation showed 83.8 ± 1.7% drug release and remained adhered to the mucosa for 24.5 ± 1 h. A higher (~ 1.85 times) drug permeation was recorded through mucosa within 6 h by in situ gelling formulation when compared to control counterparts (aqueous solution of drug and in situ gelling formulation without poloxamer 188). Nasal administration of tamsulosin HCl by using in situ gelling formulation led to a ~ 3.3 and ~ 3.5 times, respectively, higher Cmax (maximum plasma concentration) and AUCtotal (total area under the curve) than the orally administered aqueous solution. Relative bioavailability of drug delivered by nasal in situ gelling formulation was 3.5 times the oral counterpart. These results indicated that the prepared in situ gelling formulation can act as a promising candidate for systemic administration of tamsulosin HCl.

Interactional behaviour of analgesic drugs in aqueous solution of caffeine at different temperatures using multi-technique approach

Drug combination therapies have been a promising strategy to overcome drug resistance. However, unexpected drug–drug interaction may cause adverse reactions, which puts patients in danger. Keeping this in mind, the interactions between pain killers, paracetamol (PCM), and ibuprofen sodium with caffeine (CAF) have been studied. Apparent molar volumes ( V2,ϕ) and apparent molar isentropic compression ( Ks,2,ϕ) for analgesic drugs in aqueous (1, 2, 5, and 10 mmol·kg−1) CAF solutions have been determined from measured densities, ρ, and speeds of sound, u, respectively, at T = 288.15–318.15 K and at pressure p = 101.3 kPa. The results have also been interpreted in terms of various interactions occurring in the mixed solution. Calorimetrically determined negative values of ΔtrΔdil H0 indicate the exothermicity and thus the occurrence of energetically more favorable process. The hyperchromic shift (UV absorption) in the spectra of PCM in aqueous solution of CAF suggests the dominance of solute–cosolute interactions through the hydrophobic–hydrophobic/hydrophilic groups (1H NMR) of PCM + CAF system.

Versatile applications of a spectrofluorimetric approach based on photo-induced electron transfer blocking of Lurasidone

Photo-induced electron transfer (PET) is one of the most common intermolecular causes that could be responsible for the fluorescence quenching of several fluorophores. Lurasidone is one of these compounds which intrinsic fluorescence could be turned OFF“ in alkaline medium because of the PET effect of the amino group of the piperazine ring. Upon protonation of the piperazine nitrogen atom, its electron lone pair was removed, and hence the fluorescence could be recovered, and the fluorescence is turn ON. Accordingly, a new, simple, environmentally friendly, and selective approach with high sensitivity was developed for quantitation of Lurasidone hydrochloride. The technique relies on measuring the strong native fluorescence of the drug in aqueous solution, which was excited at 316 nm and emitted at 398 nm. Lower detection and quantification limits of 12.9 and 39.0 ng mL−1 were achieved. The fluorescence concentration plot was rectilinear in the range of 30–1600 ng mL−1 with a correlation coefficient of 0.9998. The drug concentrations in commercial tablets and spiked plasma were estimated using the indicated method. The suggested approach was also used to assess how closely commercial tablets complied with USP requirements for content uniformity.

DETERMINATION OF THE IONIZATION CONSTANT OF FAVIPIRAVIR API

One of the aspects of studying the physical and chemical properties of compounds is the establishment of their ionization constants. These indicators are extremely important from both a theoretical and a practical point of view. Theoretical analysis of proteolytic equilibria and potentiometric titration of an aqueous solution of an oral antiviral drug approved for the treatment of influenza in Japan, AFI favipiravir, were carried out in the paper. The presence of a hydroxy group in the third position of the pyrazine cycle in the molecule determines the ability of favipiravir to exhibit acid-base properties. According to acid-base titration, the ionization constant of Favipiravir API was determined: pKa = 5.05 ± 0.02. On the basis of the found pK value, the degree of formation of protolytic forms was calculated depending on the pH of the solution. It was established that favipiravir API in solutions exists in two protonated (non-ionized), tautomeric forms A1H and A2H and one deprotonated (ionized) form A-. Based on the calculations, the following conclusions can be drawn: - at a pH value of the solution from 0 to 3.5, approximately 100% of the substance will be in two protonated (non-ionized), tautomeric forms A1H and A2H; - at pH = 5, approximately 50% of the substance will be in two protonated (non-ionized), tautomeric forms, A1H and A2H; - at a pH value &gt; 6.5, approximately 100% of the substance will be in one deprotonated (ionized) form of A-. This is confirmed by the nature of the electronic absorption spectra of aqueous solutions of favipiravir. In the spectrum of favipiravir in a 0.1 M hydrochloric acid solution, there are two bands at the wavelengths of 322 nm and 365 nm, which correspond to the two tautomeric forms A1H and A2H. In the spectrum of favipiravir in 0.1 M sodium hydroxide solution, there is one band at a wavelength of 364 nm, which corresponds to one ionized form of A-. At the stage of pharmaceutical development, these data on the acid-base properties of the Favipiravir API can be used in the development of production technology, the creation of quality control methods and their validation, as well as in the study of the solubility of the API and the dissolution profiles of the finished medicinal product.

Effect of Tri-Sodium Citrate and Tri-Potassium Citrate on Solute–Solvent Interactions of Diphenhydramine-Hydrochloride Drug in Aqueous Solutions from the Viewpoint of Vapor Liquid Equilibria and Volumetric and Transport Properties

Effect of Tri-Sodium Citrate and Tri-Potassium Citrate on Solute–Solvent Interactions of Diphenhydramine-Hydrochloride Drug in Aqueous Solutions from the Viewpoint of Vapor Liquid Equilibria and Volumetric and Transport Properties

Solubility of Some Drugs in Aqueous Solutions of Choline Chloride-Based Deep Eutectic Solvent Systems: Experimental Data, Modeling, and the Impact of Solution pH.

The solubility of drugs in water and organic solvents is a crucial factor in numerous pharmaceutical processes. In recent years, a new type of solvent called deep eutectic solvents (DESs) has been developed as a useful solvent for drugs. Choline chloride-glycerol/urea (ChCl-G/U) systems are DESs recognized as a novel category of environmentally friendly solvents. One recent application of this type of DES in water is the solubilization of drugs. This study aimed to investigate the solubility of certain drugs in ChCl-G/U. In addition, the solubilization mechanisms of the DESs studied, and quantitative structure-property relationship (QSPR) models for solubilization were proposed. The solubility of 13 drugs in an aqueous solution of the ChCl-G/U system was investigated using the shake flask method. The study was conducted at 10% and 50% mass fractions of the studied systems. Multiple linear regression models were used to develop mathematical relationships between the solubilization of the studied compounds in the presence of ChCl-G/U + water mixture using QSPR models. The solubility of the compounds showed a significant increase upon adding ChCl-G/U to the aqueous solutions. Based on the data obtained, QSPR models were developed using solubilization ratio and structural descriptors. The experimental data demonstrates the potential of utilizing ChCl-G/U as a medium to enhance the solubility of poorly soluble drugs in water. Solubilization of solutes in ChCl-G/U + water mixtures could be correlated with the structural properties of drugs. Moreover, the final pH of the solutions in ChCl-U is a critical factor that must be considered when using this system for solubilization.

Coupling of synchronous fluorescence spectroscopy with derivative amplitude outcomes for simultaneous determination of metoprolol succinate and olmesartan medoxomil in combined pharmaceutical preparation: Application in spiked human plasma.

For the first time a spectrofluorimetric method had been achieved for the concurrent analysis of metoprolol succinate (MET) and olmesartan medoxomil (OLM). The approach depended on assessing the first order derivative (1D) of the synchronous fluorescence intensity of the two drugs in aqueous solution at Δλ of 100nm. The amplitudes of 1D at 300nm and 347nm were measured for MET and OLM, respectively. The linearity ranges were 100-1000ng/mL and 100-5000ng/mL for OLM and MET, respectively. This approach is uncomplicated, repetitive, quick, and affordable. The results of analysis had been statistically verified. The validation assessments were carried out following the recommendations of The International Council for Harmonization (ICH). This technique could be employed to assess marketed formulation. The method was sensitive with limits of detection (LOD) of 32ng/ml and 14ng/mL for MET and OLM, respectively. Limits of quantitation (LOQ) were 99ng/ml for MET and 44ng/mL for OLM. So it can be applied to determine both drugs in spiked human plasma within the linearity ranges of 100-1000ng/mL for OLM and 100-1500ng/mL for MET.

Volumetricand ultrasonic properties of thiamine hydrochloride drug in aqueous solutions of choline-based deep eutectic solvents at different temperatures

Important efforts have been made over the past years to improve the drug acts, which leads to the discovery of novel drug preparations and delivery systems. The optimal design of such processes requires a molecular-level understanding of the interactions between drug molecules and biological membranes. The thermodynamic investigation provides deep and complete knowledge of interactions and the choice of appropriate and suitable production compounds in pharmaceutical fields. Particularly, the analysis of drugs + co-solvents in aqueous media is the central issue in many types of research because they exert their impact by interacting with biological membranes. This work is aimed to measure the density and speed of sound for the thiamine hydrochloride in water + deep eutectic solvents (DESs) mixtures (choline chloride/urea, choline chloride/ethylene glycol and choline chloride/glycerol) at temperature range (293.15–308.15) K. By correlation of the evaluated parameters in some standard relations, the partial molar parameters i.e. apparent molar volumes, Vφ,m, and apparent molar isentropic compression, κs,φ,m, are calculated. In addition, apparent molar isobaric expansion, Eφ,m0, and Hepler’s constant are computed from the density and speed of sound data. For fitting the experimental Vφ,m and κs,φ,m the Redlich-Meyer equation was employed that the important quantities; standard partial molar volume, Vm0, and partial molar isentropic compression, κs,m0, were obtained. The thermodynamic analysis of the studied system also plays a crucial role in the pharmaceutical industry.

Probing Diverse Interactions of Model Amino Acids Prevalent in Aqueous Solutions of Anti-Histaminic Drug by Physicochemical Contrivance

Probing Diverse Interactions of Model Amino Acids Prevalent in Aqueous Solutions of Anti-Histaminic Drug by Physicochemical Contrivance

Pluronic F-68 Montmorillonite As A Drug Delivery Vehicle For Extended Release Of Venlafaxine Hydrochloride.

Short half-life and low bioavailability of Venlafaxine hydrochloride (VF), an antidepressant drug, necessitates the frequent administration of VF tablets in a day in order to maintain adequate drug concentration in blood plasma. This generates the need for the development of formulations which could prolong the release of VF and reduce the multiple dosages. The present work explores the combination of Montmorillonite (Mt) with Pluronic F-68 (PF-68) (OrganoMT) for oral delivery of VF. The effect of various parameters including pH of aqueous drug solution, contact time and initial drug concentration on drug loading capacity of OrganoMT has been studied. The synthesized OrganoMT-VF complexes were characterized by various suitable techniques. XRD studies indicated that the VF molecules were intercalated within the OrganoMT layers. In vitro release behavior of VF from OrganoMT-VF complexes shows an extended-release pattern for a period of 30 h and reaches upto 70% and 60% compared to pure VF having complete release time of 5.5 h and 3.5 h in simulated gastric and intestinal fluid respectively. Various kinetic models were employed to elucidate the drug release mechanism where the best fitting was obtained with Korsmeyer Peppas model. The results suggest the possibility of designing an oral extended controlled release formulation for VF to minimize its administration frequency thereby increasing the effectiveness of drug. This improves patient compliance by reducing the dose from 4 times in 24 h to once in 24 h.