Predicting the Fine Particle Fraction of Dry Powder Inhalers Using Artificial Neural Networks.

Dry powder inhalers are increasingly popular for delivering drugs to the lungs for the treatment of respiratory diseases, but are complex products with multivariate performance determinants. Heuristic product development guided by in vitro aerosol performance testing is a costly and time-consuming process. This study investigated the feasibility of using artificial neural networks (ANNs) to predict fine particle fraction (FPF) based on formulation device variables. Thirty-one ANN architectures were evaluated for their ability to predict experimentally determined FPF for a self-consistent dataset containing salmeterol xinafoate and salbutamol sulfate dry powder inhalers (237 experimental observations). Principal component analysis was used to identify inputs that significantly affected FPF. Orthogonal arrays (OAs) were used to design ANN architectures, optimized using the Taguchi method. The primary OA ANN r2 values ranged between 0.46 and 0.90 and the secondary OA increased the r2 values (0.53-0.93). The optimum ANN (9-4-1 architecture, average r2 0.92 ± 0.02) included active pharmaceutical ingredient, formulation, and device inputs identified by principal component analysis, which reflected the recognized importance and interdependency of these factors for orally inhaled product performance. The Taguchi method was effective at identifying successful architecture with the potential for development as a useful generic inhaler ANN model, although this would require much larger datasets and more variable inputs.

Efficacy, tolerability and consumer acceptability of terbinafine topical spray versus terbinafine topical solution: a phase IIa, randomised, observer-blind, comparative study.

INTRODUCTION: Tinea pedis is one of the world's most prevalent dermatophyte infections. MedSpray™ tinea pedis 1 % w/w (topical spray) is a novel, easy-to-use propellant-based spray formulation containing 1 % w/w terbinafine, requiring no manipulation at the site of infection. This is in contrast to the only formulation currently approved in Europe for single application (none are approved in the USA for single use), which is Lamisil(®) Once 1 % w/w (topical solution), containing 1 % w/w terbinafine hydrochloride, which requires manipulation on the affected area. OBJECTIVE: The aim of this study was to evaluate the efficacy, tolerability and consumer acceptability of a topical spray versus a topical solution in the treatment of tinea pedis. METHODS: This study is a phase IIa, randomised, observer-blind, non-inferiority comparative study of the topical spray compared with the topical solution over a 12-week study period. The study was conducted at Bioskin GmbH, Hamburg and Berlin. Patients (n = 120) who presented with the presence of interdigital tinea pedis caused by dermatophytes on one or both feet were enrolled in the study. Patients were randomly assigned between the two treatment groups. Either the topical spray or the topical solution was administered by the study nurse and consisted of a single application (equivalent to 20 mg of terbinafine per foot) on day 1 of the study. No further applications were made for the duration of the study. The hypothesis formulated before commencement of the study was that the topical spray would prove to be non-inferior to the topical solution. Efficacy assessments, including clinical signs and symptoms, mycology and microscopy were performed at baseline and 1, 6 and 12 weeks after treatment. RESULTS: The rate of mycological cure at week 1 was statistically equivalent for both treatments. There was a significant reduction in the overall clinical score as assessed by the Physician's Global Assessment of signs and symptoms for both treatment groups. CONCLUSION: The topical spray and the topical solution showed comparable anti-fungal activity. Furthermore, the non-inferiority of topical spray to the topical solution was confirmed as determined by the proportion of patients categorised as successfully treated at week 1. This confirms that a topical spray product, which can be applied once without touching the affected skin, is equally as effective in the treatment of tinea pedis and removes the risk of organism transfer associated with touching infected areas. CLINICAL TRIAL REGISTRATION NUMBER: EudraCT-No. 2008-002399-92.