Local anesthetics, specific agents procaine

Specific Local Anesthetic Agents. Clinically used local anesthetics and the methods of appHcation are summarized in Table 5. Procaine hydrochloride [51-05-8] (Novocain), introduced in 1905, is a relatively weak anesthetic having along onset and short duration of action. Its primary use is in infiltration anesthesia and differential spinal blocks. The low potency and low systemic toxicity result from rapid hydrolysis. The 4-arninobenzoic acid... 

Most local anesthetic agents consist of a lipophilic group (frequently an aromatic ring) connected by an intermediate chain (commonly including an ester or amide) to an ionizable group (usually a tertiary amine Table 26-1). In addition to the general physical properties of the molecules, specific stereochemical configurations are associated with differences in the potency of stereoisomers for a few compounds, eg, bupivacaine, ropivacaine. Since ester links (as in procaine) are more prone to hydrolysis than amide links, esters usually have a shorter duration of action. 

Poly(N-vinyl-pyrrolidone), or PNVP, is a biocompatible, water-soluble (JJ ) polymer that has previously been used as a synthetic blood plasma extender, as a component of soft contact lenses, and in a complex with iodine as the commercially available topical antiseptic Betadine ( ). It also forms a remarkable variety of chemically specific complexes with drugs and hormones such as the tetracyclines, phenothiazine antipsychotics, the antiepileptic drug phenytoin, procaine local anesthetics, and methyldopa antiparkinsonian drugs ( ). In its insoluble, chemically cross-linked form, PNVP has also been used as a concentrating agent for a variety of phenols and catechol compounds (22). 

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