Download Dr. Stewart: Drug Delivery Systems - Department of Surgery | Weill

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