Oxybuprocaine, also known as benoxinate or BNX, is an ester-type local anesthetic, which is used especially in ophthalmology and otolaryngology. Oxybuprocaine is sold by Novartis under the brand names Novesine or Novesin. It is formulated commonly as the hydrochloride salt for topical ocular and mucosal application (typical ophthalmic concentration 0.4 percent) and provides rapid onset of surface anesthesia, typically within 20 to 60 seconds, with an effective duration of approximately 10 to 20 minutes for diagnostic or minor procedures. Chemically it belongs to the amino ester group and is susceptible to hydrolysis by plasma and tissue esterases to para-aminobenzoic acid type metabolites; systemic absorption from ophthalmic use is minimal but increases with damaged epithelium. pH and formulation excipients affect onset and comfort; many commercial eye drop formulations are buffered to reduce instillation discomfort. Pregnant patients: safety data in human pregnancy are limited; topical ophthalmic use results in low systemic exposure, but use in pregnancy should be reserved for cases where the potential benefit justifies the potential risk to the fetus.
Parent: Oxybuprocaine
Parent: Oxybuprocaine
Parent: Oxybuprocaine / Oxybuprocaine Hydrochloride
Parent: Oxybuprocaine
The impurity profile for oxybuprocaine focuses on hydrolysis and synthetic byproducts. Related compounds commonly monitored include the de-esterified alcohol fragment, para-aminobenzoic acid type hydrolysis products, trace aromatic amines and alkylated aniline synthesis impurities, and residual solvents from manufacture. Typical specification ranges used in analytical control are individual specified impurities not greater than 0.2 percent weight by weight and total impurities not greater than 0.5 percent weight by weight as measured by a stability-indicating HPLC method. Impurities of potential toxicological concern are controlled at lower levels in accordance with ICH guidance, with reporting thresholds commonly around 0.05 percent and qualification thresholds determined by daily dose and safety assessment. Due to chemical lability, control of pH, storage temperature and avoidance of water exposure during manufacture are critical to limit hydrolytic impurity formation.
Oxybuprocaine is used as a topical surface anesthetic for the eye and for short procedures in the ear, nose and throat where mucosal anesthesia is required, such as tonometry, foreign body removal and minor surgical manipulations.
Onset is rapid, generally 20 to 60 seconds after topical application, with clinically useful anesthesia lasting about 10 to 20 minutes; repeated applications are possible but increase risk of epithelial toxicity.
Oxybuprocaine is classified as an amino ester local anesthetic, metabolized primarily by tissue and plasma esterases to para-aminobenzoic acid type metabolites; clinically it is used as a topical ophthalmic and otolaryngologic anesthetic.
Instillation can cause transient stinging or burning for some patients, particularly with unbuffered formulations or when the ocular surface is inflamed; buffered preparations and appropriate formulation excipients are used to minimize this sensation.
