Transcript Slide 1
Drug delivery systems Michael G. Stewart, MD, MPH Professor and Chairman Department of Otorhinolaryngology Paranasal sinuses & middle ear • Frequent sites of infection, inflammation • Lined by mucous membrane (mucosa) with good capacity for absorption • Current surgical management • Opening, ventilation, irrigation • Potential problems & issues • Access to cavity • Maintenance of medication dose Other potential locations • • • • Into abdominal cavity Into chest cavity Intra-vascular Directly into tissue, joint, muscle Sinus: clinical diseases • • • • • • Chronic inflammatory sinus disease Chronic infection Nasal polyps Fungal sinusitis Cystic fibrosis Other diseases of mucus and cilia transport Paranasal sinus anatomy Normal sinus CT Normal middle turbinate, left side Nasal polyps Large nasal polyp Endoscopic sinus surgery Endoscopic sinus surgery Endoscopic sinus surgery video Problems – sinus disease • Access to sinus cavities • Mucosa is source of inflammation, polyp regrowth • Inhaled solutions go directly to back of nose • Irrigated solutions go partially into some sinuses • Oral or intravenous meds go to mucosa • Problems with long-term use of steroids and antibiotics, antifungal meds Problems – sinus disease 2 • Fungal particles trapped in sinus cavity • “inside the sinus, outside the body” • Surgery to ventilate sinus is only part of solution • Bacterial overgrowth in sinus cavity • Impairment in mucus, cilia function Potential solutions - sinuses • • • • • Topical delivery system Implantable delivery system Slow-dissolving “gel” into sinus? Positive pressure aerosol? Other method of delivery • Long-term dosing directly to area • High topical dose, limited systemic absorption • Constant dosing Ear anatomy Ear disease • Middle ear • Persistent effusion • Recurrent infection or effusion • Eustachian tube block Ear disease • Inner ear – middle ear could be source of drug delivery • Meniere’s disease (recurrent vertigo) • Autoimmune inner ear disease • Sudden hearing loss • Ototoxic systemic medications • Noise trauma Normal eardrum Middle ear effusion Issues – ear disease • Easier access • Problems • requires puncturing eardrum • requires multiple procedures, doses • long-term problems, want preventative treatment in some cases Delivery system • • • • Prolonged release Steady dosing (not bolus) Remain in situ Not interfere with hearing Summary • Paranasal sinus and ear disease are very common problems • Can get access to site of disease • Need better long-term delivery and distribution of medication doses