Topical Administration
Drug delivery applied directly to the skin or mucous membrane for local effect. Peptide-based topical products include cyclosporine ophthalmic emulsion for dry eye, bacitracin antibiotic ointment, and gramicidin for wound infections.
Technical Context
Topical delivery targets the application site directly, minimising systemic exposure and side effects. Cyclosporine ophthalmic emulsion (0.05%, Restasis; 0.09%, Cequa) delivers the immunosuppressant directly to the ocular surface for dry eye disease, avoiding the nephrotoxicity and immunosuppression of systemic cyclosporine. Bacitracin ointment provides local antibiotic activity for wound infections. Gramicidin is used in ophthalmic and topical preparations, typically in combination with other antibiotics. For topical peptide delivery, molecular weight, hydrophilicity, and the stratum corneum barrier limit penetration of most peptides to the epidermis or superficial dermis without specialised delivery technologies (liposomes, penetration enhancers, microneedles).