Predicted real solubility (– log x2) and the level of hydrophilic-lipophilic balance (HLBRequ.) of phytochemicals contained in extracts isolated from linden inflorescence (Tiliae flos) with solvents of diversified polarity (εM)

Introduction: The broad spectrum of pharmacological properties of linden inflorescence extracts results from polarity and the level of hydrophilic-lipophilic balance of solvents (medium) used to separate compatible phytochemical structures with the expected pharmacotherapeutic profile.

Objective: The use of the general Hildebrand-Scatchard-Fedors theory of solubility to calculate the predicted solubility of classes of phytochemicals contained in linden inflorescences (Tiliae flos) and the indication of those structures which, due to their high solubility in the medium, are responsible for the profile of pharmacological activity.

Material and methods: The Hildebrand, Scatchard equation, supported with computational technique proposed by Fedors, allows calculation of the solubility parameters of the extraction medium. Despite application reservations, it is a fundamental tool for estimating the predictable solubility of phytochemicals in real solution.

Results: The structure of phytochemicals isolated from linden inflorescences (Tiliae flos) owing to the use of solvents of significantly diversified polarity (–dielectric constant – εM) was the basis for calculating the molar evaporation energy – ΣΔEi (cal/mol) and molar volume – ΣΔVi (cm3/mol) by Fedors method, which are fundamental quantities necessary to estimate the solubility parameter – δ1/2 and required solubility level of hydrophilic-lipophilic balance – HLBRequ.

Conclusions: Results of the presented research indicate that basing on the parameters characterizing the structure of phytochemicals and the calculated ideal (–logxi 2) and predicted real (– log x2) solubility, it is possible – using the general Hildebrand-Scatchard-Fedors theory of solubility – to choose selectively the cascade of extraction media in order to distinguish in the plant material chemical and structural individuals of different polarity.

Actual solubility (S|real.|), level of hydrophilic-lipophilic balance (HLBRequ., HLBD, HLBG) and partition coefficient (log P) of phytochemicals contained in Ext. Camellia sinensis L. aqu. siccum in the light of general Hildebrand-Scatchard-Fedors theory of solubility

Introduction: Using the general Hildebrand-Scatchard-Fedors theory of solubility, the mole fraction (x2) of solubility of phytochemicals contained in the dry green tea leaves was calculated which determines the profile of pharmacological activity.

Objective: The applicative purpose of the study was to estimate the actual solubility of phytochemicals – S|real.| [mol/dm3] in water and in water-ethanol solutions of diversified polarity (εM) for their selective extraction and optimal formulation of oral solid dosage form.

Methods: The basic physico-chemical and structural quantities of phytochemicals and corresponding mathematical equations of general Hildebrand-Scatchard-Fedors theory of solubility were used to calculate the actual solubility – S|real.| and the level of hydrophilic-lipophilic balance (HLB).

Results: The calculated actual solubility values – S|real.| [mol/dm3] collated with correlation equations enabled the assessment of phytochemical capability for the process of mass exchange on phase boundary. Correlation equations for the dependence log P = f (– log S|real.|) point to the structural preferences of phytochemicals in the kinetics of the mass exchange (diffusion) through the natural phase boundary.

Conclusions: Calculations and correlations between the values characterizing the actual solubility – S|real.|, media polarity (water, ethanol and their solutions) and the partition coefficient (log P) including the level of hydrophilic-lipophilic balance (HLB) show that basing on thermodynamic components of the general Hildebrand-Scatchard-Fedors theory of solubility, the diffusion profile of phytochemicals contained in the green tea extract (Ext. Camellia sinensis L. aqu. siccum) through the biological phase boundary as well as optimal choice of the extraction medium for selective extraction of the class of phytochemicals can be estimated.