The Role of Molecular Structure in the Crystal Polymorphism of Local Anesthetic Drugs: Crystal Polymorphism of Local Anesthetic Drugs, Part X

Abstract

This study is the first step in recognizing relationships between the structure and the solid-state properties within this limited group of active substances with common structural elements. The results clearly show that there are certain relationships, but, to understand the phenomenological behavior in more detail on a molecular level, more structural information must be collected and analyzed by computational methods.

Characterization and Comparison of Lidocaine-Tetracaine and Lidocaine-Camphor Eutectic Mixtures Based on Their Crystallization and Hydrogen-Bonding Abilities

“…Thus, the first melting endotherm (at 38.79°C) in the second heating cycle may be due to the formation of a metastable state of tetracaine, which is known to cause a decrease in the tetracaine melting point (40,41). Also, Schmidt reported melting points for tetracaine polymorphs I and II at 42 and 37°C, respectively (42). Tetracaine also shows a crystallization exotherm at 29.36°C (Fig.…”

“…The absence of hydrogen bond donor in camphor (Table II) may be used to explain the decrease of the hydrogen-bonding ability of lidocaine with camphor, which leads to crystallization from its EM as observed in the 24-h samples. In a study, Schmidt showed the importance of correlation between molecular structure and crystal polymorphism in local anesthetic drugs (42). Thus, it appears that lidocaine and tetracaine on formation of eutectic mixture interact with each other via hydrogen bonding, which retards the crystallization process of lidocaine, tetracaine, and their eutectic mixture.…”

A vibrational spectroscopic investigation on benzocaine molecule

“…Our calculation results given in Table 3 have clearly demonstrated that a good number of the fundamental bands of benzocaine have been wrongly assigned by either Alcolea Palafox [21][22][23][24] or Longarte et al [26] or both. In the light of these results, we propose reassignments for the fundamentals due to the normal modes with number 4,6,7,9,10,11,15,33,36,46,47,54,59,60, which are marked with a star character (*) in Table 4. To continue the discussion only on the conformation sensitive normal modes of the molecule will be much more preferable for both keeping the paper size shorter and determining the individual contributions of the trans and gauche conformers to the experimental vibrational spectra of benzocaine molecule.…”

“…Nowadays, synthesizing of the Schiff base ligands and their metal complexes which can show antibacterial, anticancer and herbicidal activities has become an area attracting great interest [11][12][13]; in this aspect, benzocaine has been reported as one of the preferable substances used in synthesizing of these type of structures. The structural properties of the molecule have been investigated by various workers; the polymorphic and pseudopolymorphic crystal forms of the molecule were investigated by Schmidt by means of FT-IR, FT-Raman, SSNMR spectroscopy and powder X-ray diffraction methods [14,15]. On the other hand, the experimental geometrical parameters of benzocaine in crystal form were determined in a crystallographic study carried out by Sinha and Pattabhi [16].…”

Physicochemical characterization and decomposition kinetics of (S)-4-[1-(2,3-dimethylphenyl)ethyl]-3H-imidazole HCl/S-enantiomer of medetomidineHCl

“…In some cases, improper storage of the drug (high temperatures, especially during the hot season or storage near heat sources, humidity, etc.) can reduce or even cancel the therapeutic effectiveness of drugs [28][29][30][31][32][33][34][35][36]. These reported studies have been done in different ways, and decomposition kinetics is obtained via a variety of methods.…”