Zheng JY, Fulu MY, Lee DY, Barber TE, Adjei AL. Pulmonary peptide delivery: effect of taste-masking excipients on leuprolide suspension metered-dose inhalers.
Pharm Dev Technol 2001;
6:521-30. [PMID:
11775953 DOI:
10.1081/pdt-120000290]
[Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
The purpose of this study was to evaluate the effect of taste-masking excipients on in vitro and in vivo performance of a leuprolide metered-dose inhaler (MDI) suspension formulation. Taste-masking excipients (aspartame and menthol) were added to a leuprolide suspension MDI formulation. The leuprolide MDI formulation with the taste-masking excipients was characterized in terms of milling time, particle size distribution, dose delivery and uniformity, and drug absorption in dogs. The data were compared with a formula that did not contain taste-masking excipients. It was found that the longer milling time for the leuprolide suspension with the taste-masking excipients was required to obtain a similar particle size distribution compared with the formula without taste-masking excipients using a fluid energy mill. Although measurable differences in mass median aerodynamic diameter (MMAD) and geometric standard deviation (GSD) were not observed between the two formulations, the percent of particles < or = 5 microns and the actuator retention for the formula with the taste-masking excipients were significantly different from the formula without taste-masking excipients using the Marple-Miller cascade impactor. Taste-masking excipients did not show a significant effect on valve delivery and through-can dose uniformity. However, the mean ex-actuator dose was 150.4 mg for the formula with the taste-masking excipients and 162.2 mg for the reference formula, respectively, indicating a significant difference. In tracheostomized dogs, both formulations showed comparable pharmacokinetic parameters including Cmax, Tmax, AUC0-12 and bioavailability (F%), indicating that the taste-masking excipients do not have an effect on lung absorption of leuprolide acetate. Therefore, inclusion of taste-masking excipients in the leuprolide MDI suspension formulation showed a significant impact on drug micronization, exactuator dose, and particle deposition pattern. Mechanistically, the unfavorable performance of leuprolide MDI in the presence of taste-masking excipients could be due to modification of the properties of the suspension itself and alteration of propellant evaporation following actuation.
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