Abstract
The purpose of this research was to explain the pharmacological significance of PRONES-PASTA by combining three local anesthetics. As a result, the following were determined by testing its anesthetic effect on guinea pig cornea.
1) Benzocaine demonstrated an immediate anesthetic effect when used after being dissolved in a hydrophilic vehicle containing polyethyleneglycol 4000 and propyleneglycol. However, its durability of action was found to be short, and its strength only about one fifth as great as that of tetracaine and dibucaine. Tetracaine showed a strong anesthetic effect with comparatively long durability. Dibucaine showed a strong, quick effect and long durability.
2) The relative toxicities of the local anesthetics tested calculated from the intraperitoneal LD50 value were 1 : 3.6 : 10; for benzocaine, tetracaine and dibucaine, respectively.
The conclusions are as follows; PRONES-PASTA, the ingredients of which consist of low toxicity benzocaine in a large amount, tetracaine of high strength but small in amount, and dibucaine with a long activity but a small amount, proved to be efficient from the view points of appearance, effect, durability of anesthetic action and toxicity.
