Composite method to quantify powder flow as a screening method in early tablet or capsule formulation development

The flow properties of typial tablet and capsule formulation excipients, active compounds, and representative formulation blends were tested with current and novel flow measurement techniques to identify a reliable bench test to quantify powder flow as a screening method in early tablet and capsule formulation development. Test methods employed were vibrating spatula, critical orifice, angle of repose, compressibility index, and avalanching analysis. Powder flow results from each method were compiled in a database, sorted, and compared. An empirical composite index was established and powder flow was ranked in accordance with formulator experience. Principal components analyses of the angle of repose, percent compressibility, and critical orifice of the powder materials were also performed. The first principal component accounted for 72.8% of data variability; scores associated with this principal component score can serve as an index of flowability. Data generated from vibrating spatula and avalanching methods were not reproducible and were inconsistent with formulator experience and cited vendor references for flow. Improvements of test instruments and further studies are necessary for better assessment of these approaches

Liposomal amikacin dry powder inhaler: Effect of fines on in vitro performance

The aim of the present investigation was to prepare and evaluate the influence of adding fines on the in vitro performance of liposomal amikacin dry powder inhaler (AMK LDPI) formulations. Liposomes composed of hydrogenated soyaphosphatidylcholine, cholesterol and saturated soyaphosphatidylglycerol (AMK 1), or stearylamine (AMK 2) were prepared by a reverse phase evaporation technique, extruded to reduce size and separated from unentrapped drug. Purified liposomal dispersion was subjected to lyophilization using optimized cryoprotectant to achieve maximum percentage drug retentio (PDR). Lactose carrier in varying mass ratios with or without addition of fines in different mixing sequences was used to formulate AMK LDPI formulations. AMK LDPI formulations were characterized for angle of repose, compressibility index, dispersibility index, scanning electron microscopy, and fine perticle fraction (FPF). PDR was found to be 97.6%±2.2% for AMK1 and 98.5%±1.9% for AMK2 using sucrose as optimized cryoprotectant in lipid:sucrose ratio of 1∶4. Lactose carrier containing 10% fines (wt/wt) was found to be the optimum blend at 1∶5 mass ratio of liposome:lactose. The addition of fines and the order of mixing of fines were found to influence the FPF with significantly different device fractions. FPF of AMK LDPI formulations using Rotahaler as the delivery device at 30, 60, and 90 L/min were found to be 21.85%±2.2% and 24.6%±2.4%, 25.9% ±1.8% and 29.2%±2.1%, and 29.5%±2.6% and 34.2%±2.0% for AMK1 and AMK2, respectively. From the studies performed in this investigation, it was observed that liposomal charge, addition of fines and order of mixing fines, has a significant effect (P<.05) on in vitro deposition of drug from LDPI formulation

Engineered mannitol ternary additives improve dispersion of lactose-salbutamol sulphate dry powder inhalations

The aim of this study was to evaluate the influence of novel engineered fine mannitol particles (4.7%, w/w) on the performance of lactose-salbutamol sulphate dry powder inhaler (DPI) formulations to obtain promising aerosolisation properties. The results showed that the more elongated the fine mannitol particles, the weaker the drug-carrier adhesion, the better the drug content homogeneity, the higher the amount of drug expected to be delivered to the lower airways and the higher the total DPI formulation desirability. Linear relationships were established showing that mannitol particles with a more elongated shape generated powders with broader size distributions and that were less uniform in shape. The weaker the drug-carrier adhesion, the higher the fine particle fraction of the drug is upon aerosolisation. It is believed that more elongated fine mannitol particles reduce the number of drug-carrier and drug-drug physical contact points and increase the ability of the drug particles to travel into the lower airways. Additionally, a lower drug-carrier contact area, lower drug-carrier press-on forces and easier drug-carrier detachment are suggested in the case of formulations containing more elongated fine mannitol particles. Ternary 'drug-coarse carrier-elongated fine ternary component' DPI formulations were more favourable than both 'drug-coarse carrier' and 'drug-elongated coarse carrier' binary formulations. This study provides a comprehensive approach for formulators to overcome the undesirable properties of dry powder inhalers, as both improved aerosolisation performance and reasonable flow characteristics were obtained using only a small amount of elongated engineered fine mannitol particles. © 2013 American Association of Pharmaceutical Scientists

Rapid Particle Size Measurement Using 3D Surface Imaging

The present study introduces a new three-dimensional (3D) surface image analysis technique in which white light illumination from different incident angles is used to create 3D surfaces with a photometric approach. The three-dimensional features of the surface images created are then used in the characterization of particle size distributions of granules. This surface image analysis method is compared to sieve analysis and a particle sizing method based on spatial filtering technique with nearly 30 granule batches. The aim is also to evaluate the technique in flowability screening of granular materials. Overall, the new 3D imaging approach allows a rapid analysis of large amounts of sample and gives valuable visual information on the granule surfaces in terms of surface roughness and particle shape