Thermodynamic modeling for solubility prediction of indomethacin in self-nanoemulsifying drug delivery system (SNEDDS) and its individual components

Solubilization of a novel antitumor drug ribociclib in water and ten different organic solvents at different temperatures

OBJECTIVE

This study reports new solubility and physicochemical data for ribociclib (RCB) in water and ten organic solvents including "methanol (MeOH), ethanol (EtOH), isopropyl alcohol (IPA), n-butanol (n-BuOH), propylene glycol (PG), polyethylene glycol-400 (PEG-400), acetone, ethyl acetate (EA), Transcutol-HP (THP), and dimethyl sulfoxide (DMSO)" at 293.2-313.2 K and 101.1 kPa.

SIGNIFICANCE

The obtained data are useful for the industrial applications of RCB.

METHODS

The solubility of RCB was measured and regressed using "van't Hoff, Buchowski-Ksiazczak λh, the modified Apelblat, and Jouyban models."

RESULTS

The overall deviations of <4.0% were recorded for all four models. The maximum mole fraction solubility of RCB was 2.66 × 10^-2 in PEG-400 at 313.2 K, however, the lowest one was in the water. The RCB solubility increased with temperature and the order followed in the water and ten different organic solvents was PEG-400 (2.66 × 10^-2) > THP (1.00 × 10^-2) > PG (5.39 × 10^-3) > DMSO (5.00 × 10^-3) > n-BuOH (3.23 × 10^-3) > acetone (3.11 × 10^-3) > IPA (1.58 × 10^-3) > EA (1.41 × 10^-3) > EtOH (1.37 × 10^-3) > MeOH (8.10 × 10^-4) > water (2.38 × 10^-5) at 313.2 K. The maximum solute-solvent interactions were found in RCB-PEG-400 in comparison with other combination of RCB and solvents. "Apparent thermodynamic analysis" indicated an "endothermic and entropy-driven dissolution" of RCB in water and ten organic solvents.

CONCLUSIONS

Based on all these data and observations, PEG-400 can be used as the best co-solvent for RCB solubilization.

Experimental measurement - correlation of solubility and dissolution thermodynamics study of itraconazole in pure monosolvents at various temperatures

The information about the solubility and thermodynamic properties of solution is important for pharmaceutically important processes, formulation development, and further theoretical studies. In the present study, the solid-liquid equilibrium (solubility) for itraconazole (ITC) was determined experimentally in 14 monosolvents at temperatures between 293.15 K and 318.15 K under pressure of 0.1 MPa. The mole fraction solubilities were found to increase with increasing temperatures and followed inverse trend with the polarity of selected solvents. Besides, KAT-LSER analysis was performed to study the effect of solvent. The results revealed that the solute-solvent interaction (43.94%) was much higher than that of solvent-solvent interaction (16.59%). Thermodynamic based models like van't Hoff equation, modified Apelblat equation, Buchowski-Ksiazaczak equation, and polynomial empirical equation were applied to fit and correlate the experimental solubilities. Overall relative average deviation (RAD) and overall root-mean square deviation (104×RMSD) were observed to be minimum with the empirical polynomial equation and attained the values of 0.0033 and 0.0047, respectively. Furthermore, theoretical ideal solubilities, activity coefficients, and thermodynamic properties of dissolution including molar enthalpy, molar entropy, molar Gibbs free energy, and excess enthalpy were estimated. Ideal solubilities were projected considerably higher than experimental solubilities at each studied temperature. Thermodynamic properties of dissolution indicated that the dissolution was not a spontaneous process; observed to be endothermic (ΔH0soln>0) and enthalpy driven (ΔS0soln>0). Such solid-liquid equilibrium data of ITC will be of immense help in process and formulation development in pharmaceutical sciences.

A Solid Ultra Fine Self-Nanoemulsifying Drug Delivery System (S-SNEDDS) of Deferasirox for Improved Solubility: Optimization, Characterization, and In Vitro Cytotoxicity Studies

The research work was designed to develop a solid self-nanoemulsifying drug delivery system (S-SNEDDS) of deferasirox (DFX). According to the solubility studies of DFX in different components, Peceol, Kolliphor EL, and Transcutol were selected as excipients. Pseudo-ternary phase diagrams were constructed, and then SNEDDS formation assessment studies and solubility of DFX in selected SNEDDSs formulations were performed. DFX loaded SNEDDS were prepared and characterized. The optimum DFX-SNEDDS formulations were developed. The relative safety of the optimized SNEDDS formulation was examined in a human immortalized myelogenous leukemia cell line, K562 cells, using the MTT cell viability test. Cytotoxicity studies revealed more cell viability (71.44%) of DFX loaded SNEDDS compared to pure DFX (3.99%) at 40 μM. The selected DFX-SNEDDS formulation was converted into S-SNEDDS by adsorbing into porous carriers, in order to study its dissolution behavior. The in vitro drug release studies indicated that DFX release (Q5%) from S-SNEDDS solidified with Neusilin UFL2 was significantly higher (93.6 ± 0.7% within 5 min) compared with the marketed product (81.65 ± 2.10%). The overall results indicated that the S-SNEDDS formulation of DFX could have the potential to enhance the solubility of DFX, which would in turn have the potential to improve its oral bioavailability as a safe novel delivery system.

Solubility measurement, Hansen solubility parameters and solution thermodynamics of gemfibrozil in different pharmaceutically used solvents

Gemfibrozil (GEM) is cholesterol-lowering agent which is being proposed as poorly water soluble drug (PWSD). Temperature based solubility values of GEM are not yet available in literature or any pharmacopoeia/monograph. Hence, the present studies were carried out to determine the solubility of PWSD GEM (as mole fraction) in various pharmaceutically used solvents such as water (H₂O), methanol (MeOH), ethanol (EtOH), isopropanol (IPA), 1-butanol (1-BuOH), 2-butanol (2-BuOH), ethylene glycol (EG), propylene glycol (PG), polyethylene glycol-400 (PEG-400), ethyl acetate (EA), dimethyl sulfoxide (DMSO) and Transcutol^® (THP) at the temperatures ranging from T = 298.2 K-318.2 K under atmospheric pressure P = 0.1 MPa. Equilibrium/experimental solubilities of GEM were recorded by applying a saturation shake flask methodology and regressed using 'van't Hoff and Apelblat models'. Hansen solubility parameters for GEM and various pharmaceutically used solvents were estimated using HSPiP software. The solid states of GEM (both in pure and equilibrated states) were studied by 'Differential Scanning Calorimetry' which confirmed no transformation of GEM after equilibrium. Experimental solubilities of GEM in mole fraction were observed maximum in THP (1.81 × 10^-1) followed by DMSO, PEG-400, EA, 1-BuOH, 2-BuOH, IPA, EtOH, PG, MeOH, EG and H₂O (3.24 × 10^-6) at T = 318.2 K and similar tendencies were also recorded at T = 298.2 K, T = 303.2 K, T = 308.2 K and T = 313.2 K. 'Apparent thermodynamic analysis' on experimental solubilities furnished 'endothermic and entropy-driven dissolution' of GEM in each pharmaceutically used solvent.

Dissolution thermodynamics and solubility of silymarin in PEG 400-water mixtures at different temperatures

An isothermal method was used to measure the solubility of silymarin in binary polyethylene glycol 400 (PEG 400) + water co-solvent mixtures at temperatures T = 298.15-333.15 K and pressure p = 0.1 MPa. Apelblat and Yalkowsky models were used to correlate experimental solubility data. The mole fraction solubility of silymarin was found to increase with increasing the temperature and mass fraction of PEG 400 in co-solvent mixtures. The root mean square deviations were observed in the range of 0.48-5.32% and 1.50-9.65% for the Apelblat equation and Yalkowsky model, respectively. The highest and lowest mole fraction solubility of silymarin was observed in pure PEG 400 (0.243 at 298.15 K) and water (1.46 × 10(-5) at 298.15 K). Finally, thermodynamic parameters were determined by Van't Hoff and Krug analysis, which indicated an endothermic and spontaneous dissolution of silymarin in all co-solvent mixtures.

Enhancement effect of essential oils from the fruits and leaves of Alpinia oxyphylla on skin permeation and deposition of indomethacin

Essential oils from plants are gaining increasing attention as potential chemical penetration enhancers.