Preparation and evaluation of bioadhesive benzocaine gels for enhanced local anesthetic effects.
This study was performed to develop new enhanced anesthetic benzocaine gels with a suitable bioadhesive property for local anesthetic effects. As the concentration of benzocaine in the HPMC gels increased up to 15%, the permeation of drug increased, thereafter slightly increased. The activation energy of drug permeation was 11.29 kcal/mol. Bioadhesive forces were also measured. The permeation rate of drug through the skin was studied using various enhancers, such as glycols, non-ionic surfactants or fatty acids. Among the enhancers used, diethylene glycol showed the most enhancing effects. Analgesic activity was examined using a tail-flick analgesimeter. According to the rat tail-flick test, the value of AUEC (0 - 360min) of 15% benzocaine gels containing diethylene glycol was 4662 +/- 200 s min, while that of gels without diethylene glycol was 3353 +/- 132 s min, showing about 1.39-fold increase in analgesic activity. Fifteen percentage of benzocaine gels containing diethylene glycol showed the most enhanced, prolonged analgesic effects, showing the maximum anesthetic effects at 240 min, while the gels without diethylene glycol showed maximum effect at 180 min.
Shin
Sang-Chul
SC
College of Pharmacy, Chonnam National University, 300 Yongbongdong Bukku, Kwangju 500-757, South Korea. shinsc@chonnam.chonnam.ac.kr
Lee
Jin-Woo
JW
Yang
Kyu-Ho
KH
Lee
Chi H
CH
D000268:Adhesiveness; D000277:Adjuvants, Pharmaceutic / Q000494:pharmacology; D000279:Administration, Cutaneous; D000779:Anesthetics, Local / Q000008:administration & dosage* / Q000493:pharmacokinetics / Q000494:pharmacology*; D000818:Animals; D001566:Benzocaine / Q000008:administration & dosage* / Q000493:pharmacokinetics / Q000494:pharmacology*; D005227:Fatty Acids / Q000494:pharmacology; D005782:Gels; D006018:Glycols / Q000494:pharmacology; D065347:Hypromellose Derivatives; D066298:In Vitro Techniques; D008747:Methylcellulose / Q000031:analogs & derivatives* / Q000737:chemistry; D008970:Molecular Weight; D010539:Permeability; D051381:Rats; D017207:Rats, Sprague-Dawley; D012867:Skin / Q000187:drug effects / Q000378:metabolism; D012869:Skin Absorption / Q000187:drug effects; D013501:Surface-Active Agents / Q000494:pharmacology; D013696:Temperature
D000277:Adjuvants, Pharmaceutic; D000779:Anesthetics, Local; D005227:Fatty Acids; D005782:Gels; D006018:Glycols; D013501:Surface-Active Agents; D065347:Hypromellose Derivatives; D008747:Methylcellulose; D001566:Benzocaine