A new sol-gel procedure using micellar solutions has been developed toimmobilize local anesthetic drugs in optically transparent glass. Dibucainewas selected as a direct emission probe at 77 K for determining the forms ofthe anesthetic drug (free base, monoprotonated, and/or diprotonated) and itslocation (hydrophobic core, interfacial layer or hydrophilic region) inmicelles. The photophysical properties of local anesthetics obtained in gelsare compared to those in solutions. During the gelation stage, thepredominant drug species was identified as free base dibucaine embedded inthe hydrophobic core of neutral as well as charged micelles. Thisobservation suggests that the micellar interface was modified by the largehydrophilic gel surface during the gelation stage. The modified micellarinterface allows an increase in the partition of free base dibucaine intothe hydrophobic region. At the xerogel stage, however, the collapse ofmicellar structure provides a direct interaction of dibucaine with theacidic gel surface, leading to a formation of diprotonated dibucaine. Theresults are discussed in terms of molecular basis of pharmacologicalimplications such as drug delivery, release, and transport undermicroencapsulation conditions.