1. Determination of Tetracaine Hydrochloride by Fluorescence Quenching Method with Some Aromatic Amino Acids as Probes
Xiaojuan Gan & Shaopu Liu & Zhongfang Liu & Xiaoli Hu. J Fluoresc (2012) 22:129–135
Tetracaine hydrochloride [4-(butylamino) benzoic acid 2-(dimethylamino) ethyl ester 2-(dimethylamino) ethyl 4-(butylamino) benzoate hydrochloride, TA•HCl], is an ester-type local anesthetic. This drug is very potent, long-acting agent with a low therapeutic dose, being commonly used to induce spinal anesthesia. Excessive dose and abuse of local anesthetics may cause sudden medical accidents. So it is important to determine the concentrations of local anes-
thetics in body fluids in the medical and judicial case in order to guide clinical use of local anesthetics. However, the components of body fluids are complex and the analyte is usually present at low concentration in body fluids. Therefore, it is very necessary to develop an accurate and quick examination technique for TA•HCl. According to The Pharmacopoeia of People’s Republic of China, only high concentration of TA•HCl can be determined by titration method. However, the method is tedious and time-consuming, for the samples have to be heated. Judging the end point is difficult and the sensitivity of method is low. Literature survey reveals many methods for the determination of TA•HCl concentration in pharmaceutical preparations and biological fluids such as spectrofluorometry, chemiluminesence (CL), spectrophotometry, electrochemistry method, high performance liquid chromatography (HPLC), gas chromatograph-mass spectrometer(GC-MS), resonance Rayleigh scattering (RRS), etc.
2. Effect of Temperature on the Encapsulation of the Drug Tetracaine Hydrochloride by β-Cyclodextrin and Hydoxypropyl-β-Cyclodextrin in Aqueous Medium
T. FERGOUG*, E. JUNQUERA and E. AICART∗∗.Journal of Inclusion Phenomena and Macrocyclic Chemistry 47: 65–70, 2003
Tetracaine hydrochloride (Scheme 1) belongs to an important class of synthetic drugs of the therapeutic family of local anesthetics, whose structures resemble natural compounds actively participating in nerve impulse transmission. It is believed that the cationic form of the drug, which seems to be the active principle, joins the Na+ channels on the nerve membrane, thus blocking the initiation and transmission of nervous impulses [13, 14]. However, local anesthetics often show a short duration of action, and adverse side effects, such as cardiac and neurological toxicity, accompanied sometimes by allergic reactions. It is then expected that the formulation of tetracaine hydrochloride as a microencapsulate with a cyclodextrin may show a better bioavailability, with all or some of these undesirable effects masked or abolished.