Role of nasal casts for in vitro evaluation of nasal drug delivery and quantitative evaluation of various nasal casts

Background:Nasal casts may characterize intranasal drug deposition.Methodology:The Koken cast, described as 'anatomically correct', and the Optinose cast, derived from MRI of a healthy male during velum closure, were dimensionally compared and assessed for deposition assessment suitability.Results:Smallest vertical cross-sectional areas (valve region) for Koken and Optinose right/left: 2.55/2.75 and 1.18/1.18 cm(2), respectively, versus a 'normative' mean (range) of 0.85 cm(2)(0.2-1.6 cm(2)). Intranasal volumes differed (computed tomography/water fill): Koken, 35.8/38.6 cm(3)and Optinose, 24.1/25.0 cm(3), versus a 'normative' mean (range) of 26.4 cm(3)(20.9-31.1 cm(3)).Conclusion:Koken cast dimensions are larger than the normal range and the Optinose cast. The validity of casts for regulatory drug deposition studies is suspect.