Evaluation of Hydrogels Based on Poloxamer 407 and Polyacrylic Acids for Enhanced Topical Activity of Gentamicin against Susceptible Infections

Purpose: To formulate hydrogels based on poloxamer 407 and polyacrylic acids (Carbopols (R) 971P and 974P), and evaluate its suitability for enhanced topical delivery of gentamicin, a potent but highly toxic aminoglycoside antibiotic. Methods: Topical hydrogels of gentamicin were produced using poloxamer 407 and polyacrlic acids (Carbopols (R) 971P and 974P), and evaluated in terms of drug content, pH, physical assessment, viscosity and stability. In vitro antimicrobial drug release was conducted using four microorganisms - Escherichia coli, Salmonella typhi, Staphylococcus aureus and Pseudomonas aeruginosa. Results: Stable gentamicin-loaded hydrogels with good encapsulation efficiency (maximum EE% of 85.76 to 90.66 %) as well as greater zones of inhibition against all organisms (maximum range: 22.34 +/- 2.35 to 29.40 +/- 3.07 mm) than commercially available gentamicin ointment and pure sample of gentamicin (p < 0.05), were produced. Overall, poloxamer 407 hydrogels of gentamicin gave the most desirable properties in terms of pH, viscosity and rapid concentration and time-dependent antibacterial activity on all tested micro-organisms, superior to polyacrylic acids hydrogels of gentamicin. Conclusion: This study demonstrates that poloxamer 407 hydrogels of gentamicin may offer a promising approach for topical delivery of gentamicin for the treatment of skin infections caused by gentamicin-susceptible bacteria.