title: Gamma scintigraphy for testing bioequivalence: a case study on two cromolyn sodium nasal spray preparations.
abstract: The present work was carried out to study the deposition patterns and clearance of technetium-99m (99mTc) DTPA labeled cromolyn sodium (CS) solutions when administered from two different CS nasal products using gamma scintigraphy. Five healthy volunteers received a single dose with complete crossover design involving treatment A (test formulation) and treatment B (reference formulation). The deposition patterns as well as the changes in distribution of the radiolabeled CS solutions due to the mucociliary transport were monitored by gamma scintigraphy. Primary deposition of the aforementioned nasal solutions occurred in the anterior portion of the nose. After migration into the posterior nasal cavity, the solutions were rapidly cleared by ciliary action into the nasopharynx where it was swallowed. The test product of cromolyn sodium was shown to be equivalent to the reference product with regard to nasal deposition and clearance. The results from this study indicate that external gamma scintigraphy can be used to demonstrate the equivalence of nasal sprays that are intended for local therapeutic action where the drug is not systemically absorbed into the blood circulation. Furthermore, a non-invasive imaging method such as rhinoscintigraphy may prove to be a useful technique to be utilized during the regulatory approval process for local-acting nasal products, and may facilitate the early introduction of these products to the market.
authors.affiliation: Department of Pharmaceutical Sciences, College of Pharmacy, University of Kentucky, 927 Rose Street, Lexington, KY 40536, USA. amalg0@email.uky.edu
authors.forename: Abeer M
authors.initials: AM
authors.lastname: Al-Ghananeem
authors.forename: Erik P
authors.initials: EP
authors.lastname: Sandefer
authors.forename: Walter J
authors.initials: WJ
authors.lastname: Doll
authors.forename: Richard C
authors.initials: RC
authors.lastname: Page
authors.forename: Yunik
authors.initials: Y
authors.lastname: Chang
authors.forename: George A
authors.initials: GA
authors.lastname: Digenis
mesh_terms: D000042:Absorption; D000281:Administration, Intranasal; D000328:Adult; D000336:Aerosols; D018927:Anti-Asthmatic Agents / Q000008:administration & dosage* / Q000493:pharmacokinetics*; D002626:Chemistry, Pharmaceutical; D004205:Cromolyn Sodium / Q000008:administration & dosage* / Q000493:pharmacokinetics*; D018592:Cross-Over Studies; D004305:Dose-Response Relationship, Drug; D006801:Humans; D007553:Isotope Labeling; D008297:Male; D009296:Nasal Cavity / Q000000981:diagnostic imaging* / Q000378:metabolism*; D009297:Nasal Mucosa / Q000000981:diagnostic imaging / Q000378:metabolism; D011877:Radionuclide Imaging; D019275:Radiopharmaceuticals; D016284:Technetium Tc 99m Pentetate; D013810:Therapeutic Equivalency
chemical_list: D000336:Aerosols; D018927:Anti-Asthmatic Agents; D019275:Radiopharmaceuticals; D004205:Cromolyn Sodium; D016284:Technetium Tc 99m Pentetate