Mobile aliphatic domains in humic substances and their impact on contaminant mobility within the matrix.

Using a novel NMR option, magic angle spinning pulsed field gradient (MAS PFG) NMR, the mobility of aliphatic domains in humic substances in the presence of toluene (about 4.5 wt. %) has been monitored.

Characterisation and functionality of inhalation anhydrous lactose.

The relationships between the physicochemical properties and functionality in dry powder inhaler (DPI) performance was investigated for inhalation grade anhydrous lactose and compared to monohydrate grades. The excipients were characterised using a range of techniques including particle size analysis, moisture sorption and powder rheometry. The inhalation anhydrous lactose grades were readily characterisable.

The role of fines in the modification of the fluidization and dispersion mechanism within dry powder inhaler formulations.

Purpose: To investigate the role of in situ generated fine excipient particles on the fluidization and aerosolization properties of dry powder inhaler (DPI) formulations.

Materials And Methods: Carrier based DPI formulations were prepared under low and high shear blending. Powder rheometery was utilized to measure bulk powder properties in a consolidated and aerated state.

Influence of fine lactose and magnesium stearate on low dose dry powder inhaler formulations.

The behaviour of dry powder blends for inhalation, depending on the amount of fine lactose particles smaller than 10microm and the presence of magnesium stearate (MgSt), was studied in this work. A laser light diffraction method was developed to determine accurately size and volume fraction of these fine lactose particles in coarse carrier lactose (x(50) approximately 220microm). A linear relationship between measured volume fraction undersize at 10microm Q(3)(10microm) and added fine lactose could be established.

Influence of particle size and shape on flowability and compactibility of binary mixtures of paracetamol and microcrystalline cellulose.

The influence of the size and shape of paracetamol particles on the flow and compression behavior of blends (1:1) of microcrystalline cellulose (MCC) was investigated. The effect of paracetamol particle shape was investigated by using two differently prepared samples, micronized and novel engineered Solution Atomization and Xstallization by Sonication (SAXS) particles, which exhibited similar particle size ranges (2-6 microm). The results were compared to data obtained for an untreated paracetamol sample.

Processing of spherical crystalline particles via a novel solution atomization and crystallization by sonication (SAXS) technique.

Purpose: The objective was to develop a single-step pharmaceutical particle engineering technique able to produce particles within a well-defined particle size range while controlling macroscopic spherical morphology and mesoscopic surface topography.

Methods: Paracetamol (acetaminophen) aerosol droplets were generated by spraying a solution via either an electrohydrodynamic atomizer (EHDA) or an air pressure atomizer. The highly supersaturated droplets were collected in a suitable nonsolvent of the drug and crystallized by ultrasonication.

The effect of mechanical processing on surface stability of pharmaceutical powders: visualization by atomic force microscopy.

Atomic force microscopy was used to investigate the influence of mechanical processing (milling) on the surface stability of salbutamol sulfate. Phase imaging, a development of tapping mode atomic force microscopy, was used to elucidate variations in the physico-mechanical properties on the surface of salbutamol sulfate crystals by measuring the phase lag of an oscillating tip in contact with the surface. Simultaneous measurements of topographical and phase images indicated an increase in disorder on the surface as milling time was increased.