Summary of abbreviated impactor measurement workshop organized by the European Pharmaceutical Aerosol Group.

This year, the Drugs Delivery to the Lungs 21 conference broke new ground with the first half-day devoted to a workshop focusing on experimental aspects of the abbreviated impactor measurement concept. The workshop had the following objectives: to define what further needs to be done experimentally to establish abbreviated impactor measurement; and to identify the pathway towards adoption of existing methods into the pharmacopeias, as the next step towards what is hoped will eventually be acceptance by the key regulatory agencies in Europe, Canada and the USA.

Drug delivery to the Lungs 21.

Drug Delivery to the Lungs 21 was focused exclusively on delivery technologies of medicines for the treatment of diseases that are 'local' to the respiratory tract or for wider 'systemic' distribution. Therefore, the range of diseases that can be treated via delivering drugs to the lungs is large and diverse. This diversity means that the delivery technologies (device and/or formulation) are also very varied.

Cascade impactor (CI) mensuration--an assessment of the accuracy and precision of commercially available optical measurement systems.

Multi-stage cascade impactors (CIs) are the preferred measurement technique for characterizing the aerodynamic particle size distribution of an inhalable aerosol. Stage mensuration is the recommended pharmacopeial method for monitoring CI "fitness for purpose" within a GxP environment. The Impactor Sub-Team of the European Pharmaceutical Aerosol Group has undertaken an inter-laboratory study to assess both the precision and accuracy of a range of makes and models of instruments currently used for optical inspection of impactor stages.

Minimizing variability of cascade impaction measurements in inhalers and nebulizers.

The purpose of this article is to catalogue in a systematic way the available information about factors that may influence the outcome and variability of cascade impactor (CI) measurements of pharmaceutical aerosols for inhalation, such as those obtained from metered dose inhalers (MDIs), dry powder inhalers (DPIs) or products for nebulization; and to suggest ways to minimize the influence of such factors. To accomplish this task, the authors constructed a cause-and-effect Ishikawa diagram for a CI measurement and considered the influence of each root cause based on industry experience and thorough literature review. The results illustrate the intricate network of underlying causes of CI variability, with the potential for several multi-way statistical interactions.

Product Quality Research Institute evaluation of cascade impactor profiles of pharmaceutical aerosols. Part 3. Final report on a statistical procedure for determining equivalence.

The purpose of this article is to report final results of the evaluation of a chi-square ratio test proposed by the US Food and Drug Administration (FDA) for demonstrating equivalence of aerodynamic particle size distribution (APSD) profiles of nasal and orally inhaled drug products. A working group of the Product Quality Research Institute previously published results demonstrating some limitations of the proposed test. In an effort to overcome the test's limited discrimination, the group proposed a supplemental test, a population bioequivalence (PBE) test for impactor-sized mass (ISM).

Studies of the human oropharyngeal airspaces using magnetic resonance imaging IV--the oropharyngeal retention effect for four inhalation delivery systems.

Magnetic resonance imaging (MRI) of the oropharyngeal region from 20 adult volunteers using four model inhalation devices (varying mouthpiece diameters, airflow resistances) and tidal breathing was carried out. Statistical analysis (convex hull method) selected 12 scans from 80 data sets representing the extremes of all dimensions in the population. Twelve physical mouth-throat models were made by stereolithography using the exact scan data.

Laser diffractometry as a technique for the rapid assessment of aerosol particle size from inhalers.

The rapid assessment of aerosols produced by medicinal inhalers is highly desirable from several standpoints, including the assurance of product quality, the development of new delivery systems, and the need to meet an increasing requirement by regulatory bodies for reliable in vitro performance data. Particle size analysis has traditionally been undertaken by cascade impactor on account of the direct assessment of active pharmaceutical ingredient(s) (APIs) that is possible by this method. However, laser diffractometry is less labor-intensive, more rapid, and can be a less invasive procedure.

Using multidetector CT for preoperative vascular evaluation of liver neoplasms: technique and results.

Objective: The purpose of our study was to evaluate the performance of CT angiography using multidetector CT (MDCT) for preoperative vascular evaluation in candidates who were scheduled for liver neoplasm resection.

Subjects And Methods: Forty-two consecutive subjects with malignant liver tumors scheduled for resection were studied with multiphase MDCT. The first 22 subjects underwent both multiphase MDCT angiography and catheter angiography before surgery.