Development of lidocaine oral mucoadhesive patches

Abstract

The purpose of this present study was to prepare mucoadhesive patch for oral mucosal administration of lidocaine base and lidocaine HC1 as a viable alternative dosage form to lidocaine injection for dentistry. The mucoadhesive patch was prepared as three layers, backing layer (ethyl cellulose), drug matrix film layer by using HPMC El5, PEG 400 and propylene glycol at ratios of drug : HPMC El5: PEG 400 : propylene glycol 2:1:4:1.5 (lidocaine base), 2:1:4:1 (lidocaine HC1) and mucoadhesive layer (Carbopol 934P). Each patch contained 45 mg of active ingredient. The adhesive properties, morphology, physicochemical properties, in vitro release and penetration and stability of the preparations were evaluated and compared with the commercial product (Dentipatch®). Comparision between lidocaine base, lidocaine HC1 and Dentipatch® showed that the obtained patches were flexible to be used along the curvature of the oral cavity. Lidocaine base patch was translucent while lidocine HC1 patches and Dentipatch® were transparent. Lidocaine base patch had no significant different mucoadhesive strength from Dentipatch® while lidocaine HC1 patch was less mucoadhesive. The physicochemical characterization of patches showed that lidocaine base and Dentipatch® were in solid dispersion form while lidocaine HC1 patches was in amorphous form. The release kinetic of the drug through and without dialysis membrane were fitted with first order model. The release rate through dialysis membrane was significantly slower than that without dialysis membrane. Lidocaine HC1 patch was significantly released without dialysis membrane faster than lidocaine base patch and Dentipatch® (p<0.05) while the release from lidocaine base patch and Dentipatch® had no significant different (p>0.05). The obtained patches were not stable even within the self-prepared packaging therefor protection from moisture and high temperature had to considered.