The results obtained will serve to optimize the transformation of the compound into a pharmaceutical agent
A group of researchers led by Professor Alexander Knyazev at the Faculty of Chemistry of Lobachevsky State University (Nizhny Novgorod, Russia) has been studying the thermodynamic properties of L-carnitine for several years. There is only a limited number of substances that have proven their effectiveness and safety in the course of long-term observation and at the same time offer such advantages as acceleration of recovery after exercise or the ability to eliminate body dysfunctions associated with intense exercise.
Among such substances, several compounds, including L-carnitine, attract the greatest attention of experts. This substance has gained special popularity as a corrector of energy metabolism, which improves mainly aerobic performance. Preparations based on this compound are particularly popular among athletes, since intense physical exertion almost always leads to a lack of L-carnitine in the body.
This substance has also received substantial attention of Lobachevsky University researchers who have studied its physico-chemical properties.
Biologically active substances are used in food and pharmaceutical industry, agriculture, animal husbandry, cosmetology and dermatology. They also find application as natural dyes and in the production of biologically active additives.
The production of synthetic biologically active substances opens up great opportunities for the development of medicine. However, this requires detailed information about their properties to enable the development and improvement of existing methods for obtaining and purifying these substances using computer programs. Such specialized software allows for computer synthesis based on the data chosen as the main criteria for programming, including the structure of compounds, thermodynamic parameters of substances, and chemical reactions.
“The study of structural properties and polymorphism is also of great importance for the pharmaceutical industry, since polymorphic forms of a medicinal agent may have different physical and chemical properties, such as solubility, dissolution rate, chemical and physical stability, fluidity, water absorption, flow properties, suitability for tableting, biological activity, bioavailability and toxicity. The data on these properties are extremely important at the stage when the therapeutic forms of the substance are developed,” emphasizes Professor Alexander Knyazev.
Therefore, in the course of the research, the temperature dependence of the heat capacity of levocarnitine was investigated, standard thermodynamic functions such as heat capacity, entropy, enthalpy and Gibbs function of heating were obtained for the temperature range from T ? 0 to 346 K; standard thermodynamic functions of vitamin ?11 production were calculated at T = 298.15
“In the present work, the temperature dependence of the heat capacity of L-carnitine in the range from 6 to 346 K was measured for the first time using the method of precise adiabatic vacuum calorimetry. Based on experimental data, the thermodynamic functions of L-carnitine, namely the heat capacity, the enthalpy H ° (T) – H ° (0), the entropy S ° (T) – S ° (0) and the Gibbs function G ° (T) – H ° (0) were determined for the range from T ? 0 to 350 K,” notes Alexander Knyazev.
The value of the fractal dimension D in the function of the multifractal generalization of Debye’s theory of the heat capacity of solids was evaluated, as was the nature of the structure’s heterodynamics. The enthalpy of L-carnitine combustion (-4142.1 ± 2.3) kJ mol was first measured using a high-precision combustion calorimeter. The standard molar enthalpy of L-carnitine formation in the crystalline state (-756.2 ± 2.5) kJ mol at 298.15 K was obtained from combustion experiments.
Using a combination of adiabatic calorimetry and combustion calorimetry results, the thermodynamic functions of L-carnitine formation were calculated at T = 298.15 K and p = 0.1 MPa. Low-temperature X-ray diffraction was used to determine thermal expansion coefficients.
“In the course of our research, we have studied the properties of the substance, which is important for improving the methods for its production and for developing its dosage form. Besides, using these data, it is possible to judge whether certain processes can or cannot occur in the body with the participation of the substance under study,” says Professor Alexander Knyazev in conclusion.