Improvement of Lidocaine Local Anesthetic Action Using Lallemantia royleana Seed Mucilage as an Excipient.

Lallemantia royleana (Balangu) is a well known Iranian medicinal plant that its seed mucilage has many applications in modern pharmacology. Plant mucilage traditionally was used as a gel supplement, and natural matrix for sustained release of drugs. But it seems that these compounds are not a simple additive and also have many undiscovered pharmacological properties. In this research, the anesthetic action of gel prepared from Balangu mucilage alone and its mixture with lidocaine hydrochloride are compared with the effect of commercial 2% lidocaine gel by rat tail flick test. Mucilage of Balangu seed alone showed analgesic effect. Duration and potency of anesthesia induced by gel containing mucilage alone (0.01 g/mL) were identical to commercial 2% lidocaine gel. But, local anesthetic potency and duration of gel made from 2% lidocaine-mucilage gel mixture was significantly higher than commercial 2% lidocaine gel. The gel prepared from mucilage causes a good analgesia with unknown mechanism. Besides, mixture of Balangu mucilage prepared gel with lidocaine improves lidocaine anesthesia. The increase in potency of lidocaine action results from mucilage dermal penetration enhancing effects; and longer anesthetic duration of this mixture are related to the capability of mucilage based gel for sustained drug release.