Formulation, Characterization and Antibacterial Study of Microsponges Loaded Gel of Clarithromycin for Topical Drug Delivery

Microsponge drug delivery systems comprise of spherical and porous microspheres used for prolonged topical drug delivery. These systems considerably reduce the undesirable side effects, offering improved patient compliance and reduced dosing frequency. The present study was focused on the development of topical controlled release preparations of microsponges loaded gel of clarithromycin with the purpose to cure bacterial skin infections. Four batches of Microsponges (F1, F2, F3, and F4) of clarithromycin (CLR) containing fixed amounts of clarithromycin (100 mg), Dichloromethane (5 ml), polyvinyl alcohol (5 % w/v) and distilled water (25 ml) with varying polymer concentrations were prepared by quasi-emulsion solvent diffusion method and evaluated for % Production Yield, % drug content, % encapsulation efficiency, particle size, polydispersity index (PDI) and % drug release characteristics. The selected Microsponges formulation (F3) was incorporated in Carpopol 934 gel for topical application. The prepared gel (CLRMS-F3 Gel) was evaluated for physical characteristics, pH, spreadability, viscosity, and in vitro drug release. Furthermore, the gel formulation was compared with pure clarithromycin gel for antibacterial activity against Gram positive stain (S. aureus) and Gram negative (E. coli.) by cup and plate method. The F3 microsponge formulation exhibited a production yield of 83.75%, drug content (21.5 ± 0.50 %), encapsulation efficiency of 86.04 ± 2.30%. Their particle size was satisfactory (3.80 ± 0.01 µm) and they were found to be spherical and porous in nature. F3 microsponges released 69.36 ± 1.27 % of the drug over a period of 8 hrs and were incorporated into the gel formulations. The gel prepared using F3 microsponges was transparent, homogenous and exhibited pH of 6.8 ± 0.02, Spreadability 9.92 ± 0.44 g/cm and viscosity 35370.17 ± 493.09 centipoise. The CLRMS-F3 gel released 82.13 ± 0.47 % drug in 12 hrs by zero-order kinetic. The antibacterial activity studies revealed a higher potency against both S. aureus and E. coli of the prepared CLRMS-F3 gel in comparison to both pure CLR gel and azithromycin standard. On the basis of the above study, it may be concluded that microsponges gel formulation can be potentially useful in improving topical drug delivery of antibacterial agents and can give better therapeutic efficacy.