Tetracaine structure

Testosterone, conformation of, 129 molecular model of, 129 structure and function of, 1082 Tetracaine, structure of, 967 Tetrahedral geometry, conventions for drawing. 8... 

The ending caine stems from cocaine, the first clinically employed local anaesthetic. Procaine and tetracaine are ester-linked substances, the others are amides. Amide bonded local anaesthetics usually contain two i s in their name, ester-bonded only one. In the structure drawings, the lipophilic portion of the molecule is depicted at the left, the amine at the right. The asterisk marks the chiral centre of the stereoisomeric drugs. Lipid solubility is given as the logarithm of the water octanol partition coefficient, log(P). 

Some other anesthetics with similar structures are prilocaine, tetracaine, ropivacaine, bupivacaine, chloroprocaine, and mepivacaine ... 

Local anesthetics interact with peripheral nerve cell membranes and exert a pharmacological effect [34]. Potential oscillation was measured in the presence of 20 mM hydrochlorides of procaine, lidocaine, tetracaine, and dibucaine (structures shown in Fig. 16) [19]. Amplitude and the oscillatory and induction periods changed, the extent depending on the... 

FIG. 16 Chemical structures of (a) procaine hydrochloride, (b) lidocaine hydrochloride, (c) tetracaine hydrochloride, and (d) dibucaine hydrochloride. 

FIG. 1 Molecular structures of the drugs examined in the delivery study the general anesthetics, alkanols (I), halothane (II), enflurane (III), isoflurane (IV), halogenated cyclobutane (V) the local anesthetics, dibucaine hydrochloride (VI), procaine hydrochloride (VII), tetracaine hydrochloride (VIII), lidocaine hydrochloride (IX), benzyl alcohol (X) the endocrine disruptor, bisphenol A (XI), and alkylbenzenes, benzene (XII), toluene (XIII), ethylbenzene (XIV), and propylbenzene (XV). 

Local anesthetics are positively charged amphiphiles in solution. We have selected hydrochlorides of dibucaine (DBC H ), procaine (PRC H ), tetracaine (TTC H ), and lido-caine (LDC H ). All of these drugs are structurally similar they consist of the substituted benzene ring and tertiary amine moieties, as shown by (VI)-(IX) in Fig. 1. The presence of the positive charge increases the solubility in water and in consequence, the anesthetic efficiency. 

Shimooka, T., Shibata, A. and Terada, H. (1992). The local anesthetic tetracaine destabilizes membrane structure by interaction with polar headgroups of phospholipids, Biochim. Biophys. Acta, 1104, 261-268. 

Tetracaine Tetracaine, the 2-diethylaminoethyl ester of 4-butylaminobenzoic acid (2.1.6), is also structurally analogous to procaine, in which the amino group of the benzene ring is replaced by a butylamine radical. The methods for its synthesis are the same as the above-mentioned methods for procaine or chloroprocaine, with the exception of using 4-butylaminobenzoic acid in place of 4-aminobenzoic acid. There is also a proposed method of synthesis that comes directly from procaine (2.1.1). It consists on its direct reaction with butyric aldehyde and simultaneous reduction by hydrogen using a palladium on carbon catalyst [6]. 

Benzonatate Benzonatate, p-butylaminobenzoate 2,5,8,11,14,17,20,23,26-nonaocta-cozan-28-ol (23.2.2), is synthesized by reesterifying the ethyl ester of 4-butylaminoben-zoic acid with the monomethyl ether nonaethylenglycol. It is a structural analog of the local anesthetic tetracaine [3,4],... 

A series of dibenzazonines with the general structure 111 (R, R, = H, alkyl, alkoxy, halo R2 = H, alkyl R3 = H, alkyl, alkanoyl n = 1,2) were prepared from thebaine (45) and found to have antiarrhythmic activity similar to that of procainamide and local anaesthetic activity lasting longer than that of tetracaine (45). One compound of this series, named asocainol (111, R = R, = H, R2 = Me, R3 = H, n = 2), is a useful drug whose mechanism of action in isolated guinea pig papillary muscles has been studied in detail (78, 79). 

Cross-sensitization between proxymetacaine and tetracaine is thought to be rare. Moreover, the chemical structure of proxymetacaine is sufficiently different from tetracaine to make cross-reactivity unlikely. This case suggests, however, that some degree of cross-sensitization can occur. 

Broadly speaking, it has been observed critically amongst all the known local anaesthetics , which are invariably employed in clinical practice, that there exists no clear-cut and obvious structure activity relationship in them. Besides, a plethora of these clinically prevalent and useful local anaesthetics are importantly tertiary amines , such as Butacaine, Bupivacaine, Dibucaine, Lidocaine, Mepivacaine, Prilocaine, Pramoxine, Proxymetacaine, Tetracaine etc. 

Examples Possible resonance structures of procaine, lidocaine and tetracaine are as describe below ... 

Following the introduction of procaine, hundreds of structurally related analogues were prepared and their local anesthetic properties examined. Most of these compounds were prepared for the purposes of enhancing the intrinsic potency and the duration of action of procaine. Among these compounds, tetracaine remains the most potent, long-acting ester-type local anesthetic agents used in spinal anesthesia. 

Later the structure of procaine was modified to obtain, for particular medical uses, a substance which could easily penetrate mucous membranes. A redistribution of lipophilic groups gave the much-used local anaesthetic, tetracaine (amethocaine, Decicain ) 7.12) (these steps are reviewed by Barlow, 1968). It is now known that a tremendous number of chemicals have local anaesthetic... 

These local anesthetics, including lidocaine (Xylocaine), mepivacaine (Carbo-caine), Prilocaine (Citanest), and bupivacaine (Marcaine) are weak sensitizers, but allergic reactions are sporadically reported, e. g., lidocaine (Turner 1977). Recently Fregert et al. (1979) described two patients developing lidocaine allergy after 8 and 1 month use of Xyloproct ointment (lidocaine 5%, hydrocortisone acetate) they also had positive patch tests to related amide anesthetics, both to mepivacaine, one to bupivacaine and prilocaine. A positive reaction to the chemically unrelated cincaine was interpreted as concomitant sensitivity rather than cross-sensitivity. Safe substitutes for benzocaine-sensitive patients include lidocaine, mepivacaine, prilocaine, bupivacaine, and pyrocaine (Fisher 1973 p. 312), all based on an amide structure. Lidocaine-sensitive patients may use tetracaine (pontocaine), a derivative of aminobenzoic acid. 

One of the first uses of local anesthetics (LA) for anesthesia was in the late nineteenth century with William Halsted reporting a mandibular block and brachial plexus block using cocaine [37,38]. The chemical structure of local anesthetics in clinical use consists of an aromatic (lipophilic) benzene ring linked to an amino group (hydrophflic) via either an ester or an amide intermediate chain. The intermediate link classifies the local anesthetic as either an ester (procaine, chloroprocaine, tetracaine, and cocaine) or an amide (lidocaine, prilocaine, mepivacaine, bupi-vacaine, etidocaine, and ropivacaine). 

Chemical structure Udocaine, see Figure 68.4 tetracaine, see Figure 68.5... 

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