Lactose particle size

Fielden KE, Newton JM, Rowe RC. The influence of lactose particle size on spheronization of extrudate processed by a ram extruder. Int J Pharm 1992 81 205-224. 

Eielden, K.E. Newton, J.M. Rowe, R.C. The Effect of Lactose Particle Size on the Extrusion Properties of Microcrystalline Cellulose-Lactose Mixtures. J. Pharm. Pharmacol. 1989, 41, 217-221. 

C (typical) for commercial anhydrous lactose. Particle size distribution see Table 11. 

E. Guenette, A. Barrett, D. Kraus, R. Brody, L. Harding, G. Magee, Understanding the effect of lactose particle size on the properties of DPI formulations using experimental design. International Journal of Pharmaceutics, 380,80-88,2009. 

Sample Gas injection Gas used Pressure (bar) Drying air temperature ln(°C) Out( C) Moisture [%) Crystalline lactose %) Particle size (pm) Physical properties... 

Fraunhofer rules do not include the influence of refraction, reflection, polarization and other optical effects. Early Iziser particle analyzers used Fraunhofer approximations because the computers of that time could not handle the storage cuid memory requirements of the Mie method. For example, it has been found that the Fraunhofer-based instrumentation cannot be used to measure the particle size of a suspension of lactose (R.I. = 1.533) in iso-octane (R.I. = 1.391) because the relative refractive index is 1.10, i.e.- 1.533/1.391. This is due to the fact that diffraction of light passing through the particles is nearly the same as that passing around the particles, creating a combined interference pattern which is not indicative of the true... 

Flow behavior of powders is also of interest in direct compression. It is generally accepted that the flow rate initially increases with particle size, achieves a maximum in the range of 100-400 /um, and then decreases [85]. An excipient that has been well characterized is lactose, which undergoes particle fragmentation when compacted. For a-lactose monohydrate, it has been shown that the... 

Many surface area studies have investigated various properties of excipients. The relationship between excipient grades, flow properties, particle sizes, and surface areas have been studied. Fast-flo lactose is manufactured to contain larger particles (approximately 50 jim) than hydrous lactose (approximately 20 /zm) [23], This has been done to improve the flow properties of the fast-flo... 

Frake et al. compared various chemometric approaches to the determination of the median particle size in lactose monohydrate with calibration models constrncted by MLR, PLS, PCR or ANNs. Overall, the ensuing models allowed mean particle sizes over the range 20-110/tm to be determined with an error less than 5 pm, which is comparable to that of the laser light diffraction method nsed as reference. Predictive ability was similar for models based on absorbance and second-derivative spectra this confirms that spectral treatments do not suppress the scattering component arising from differences in particle size. 

P. Frake, I. Gill, C.N. Luscombe, D.R. Rudd, J. Waterhouse and U.A. Jayasooriya, Near-infrared mass median particle size determination of lactose monohydrate, evaluating several chemometric approaches. Analyst, 123, 2043-2046 (1998). 

Figure 9 Cumulative particle size distribution of the agglomerates at a fixed normalized amount n (=0.62) of granulating liquid for different ratios of the binary powder mixture lactose/corn starch.

Gereg and Capolla developed process parameters determined by a model laboratory bench scale Carver press, model C (Carver Inc. Savannah, Georgia, U.S.A.), which were translated to production scale compactor parameters (6). Their study provided a method to predict whether a material is suitable for roller compaction. Their study objectives were to characterize properties of the material to identify process parameters suitable to achieve the necessary particle size and density using the dry granulation process and then translate laboratory information to a production scale roller compactor. Actually, information developed from a Carver press was correlated and scaled-up to a production scale Fitzpatrick roller compactor. Model IR 520 (Fitzpatrick Co., Elmhurst, Illinois, U.S.A.) The compactor produced very similar powder granule characteristics as the Carver press. Various lactose materials, available as lactose monohydrate or spray dried lactose monohydrate, were used as the model compounds. Results indicated that a parametric correlation could be made between the laboratory bench Carver press and the production scale compactor, and that many process parameters can be transferred directly. 

Controlled optimal particle size and size distribution ensures superior flow properties of coprocessed excipients and reduced reliance on addition of glidants. The volumetric flow properties of SMCC were studied in comparison with those of the physical mixture of its parent excipients (42). The particle size range of the two test samples was found to be similar, but the flow of coprocessed excipient was better than that of the physical mixture. A comparison of the flow properties of Cellactose with its parent excipients was also performed (5) by measuring the angle of repose and Hausner ratio, and Cellactose was found to have better flow characteristics than lactose or a physical mixture of cellulose and lactose. The spray-dried coprocessed product had a spherical shape and even surfaces, which resulted in improved flow properties. On similar terms, mechanically coating the 2% CSD over microfine cellulose powder resulted in improving its flow properties (43). 

Masaki H, Akinobu O, Fukuji H. Effect of particle size of lactose on the compaction properties of powder and tensile strength of tablets. Yakuzaigaku 1986 46(l) 50-57. 

Riepma KA, Lerk CF, De Boer AH, Bolhuis GK, Kussendrager KD. Consolidation and compaction of powder mixtures. I. Binary mixtures of same particle size fractions of different types of crystalline lactose. Int J Pharma 1990 66(l-3) 47-52. 

Zeng XM, Martin GP, Tee SK, Ghoush AA, Marriott C. Effects of particle size and adding sequence of fine lactose on the deposition of salbutamol sulphate from a dry powder formulation. Int J Pharma 1999 182 133-144. 

Lactose hydrolysis with immobilized systems is the method of choice when regular production of hydrolyzed syrups on a large scale is required. The best-known of these is the Corning immobilized system, which uses lactase from Aspergillus niger covalently bound to a controlled-pore silica carrier. The particle size is 0.4 to 0.8 mm, the wet bulk density is 0.6, the activity is near 500 U/g at 50°C, and the optimal pH of operation is between 3.2 and 4.3. Estimated laboratory life is 2 years (Dohan et al. 1980). There are at least two of these plants in commercial operation, one in the Untied States and one in the United Kingdom, each a joint venture with Corning. 

Elversson, J., A. Millqvist-Fureby, G. Alderborn, and U. Elofsson. 2003. Droplet and particle size relationship and shell thickness of inhalable lactose particles during spray dtjnP arm Sci 92 900-910. 

FIGURE 20.5 Cumulative particle size distribution pt= 0.62 for different ratios of the binary mixture lactose (L)/corn starch (MS). The granule diameter is critically linked to the concentration ratio (percolation effect ). (From Leuenberger, H., Usteri, M., Imanidis, G, and Winzap38ll,. Chem. Farrn 128, 54-61... 

The carrier properties have been studied in numerous in vitro studies to understand the influence on powder performance, especially drug detachment. The particle size distribution of the carrier is of paramount importance for the delivery and dispersion of drug particles by a device at given flow-rate conditions (Steckel and Mueller 1997 French et al. 1996 Kassem et al. 1989). An increased proportion of fine particles results in more efficient dispersion (Podczeck 1999), which has led to the proposal to deliberately add microfine lactose as a ternary agent (Lukas et al. 1998). 

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