Formulation of Bioadhesive Carbomer Gel Incorporating Drug-Loaded Gelatin Microspheres for Periodontal Therapy

Purpose: To formulate carbomer gel to localize and target drug action in periodontal pockets. Methods: Diclofenac sodium (DS, anti-inflammatory) and metronidazole hydrochloride (MH, antibacterial) were loaded in gelatin microspheres using glutaraldehyde cross-linking. The microspheres were evaluated for drug loading, entrapment and encapsulation efficiency, particle size, drug release as well as by scanning electron microscopy (SEM) and differential scanning calorimetry (DSC). The microspheres were incorporated into carbomer gel and evaluated for drug release. Results: Loading, entrapment and encapsulation efficiencies of DS in the microsphere were 23.4, 93.6, and 74.9 w/w%, respectively, while for MH the values were 21.5, 86.0 and 73.1 % w/w, respectively. Mean particle size of unloaded microspheres, DS- and MH-loaded microspheres was 33.5, 67.8 and 51.4 μm, respectively. SEM showed spherical geometry of microspheres while DSC indicated the amorphous nature of t entrapped DS and MH. Sustained release of DS and MH over a 4-h period from the microspheres and gel was achieved. Conclusion: Carbomer gel loaded with microspheres of diclofenac and metronidazole is a potential localized delivery system for the treatment inflammation and infection in periodontal pockets.