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Solid State Testing of Inhaled Formulations
Published in Anthony J. Hickey, Sandro R.P. da Rocha, Pharmaceutical Inhalation Aerosol Technology, 2019
Philip Chi Lip Kwok, Hak-Kim Chan
Density equals mass divided by volume. However, there are several types of densities with regards to solids, depending on what volume is included in the measurement. True density of a compound is the mass divided by the volume of the atomic or molecular unit cell in a crystal, without voids. It can be derived from X-ray diffraction data on the composition and volume of a unit cell (British Pharmacopoeia 2017, European Pharmacopoeia 2017). Pycnometric density is obtained by measuring the volume occupied by a powder in a gas displacement pycnometer (British Pharmacopoeia 2017, European Pharmacopoeia 2017, United States Pharmacopeia 40-National Formulary 35 2017). There are two chambers in the gas pycnometer, namely, a calibrated test chamber with volume Vc and an expansion chamber with volume Vr. They are connected by a valve in between. A known mass of powder is first put into the test chamber. After closing the pycnometer and with the valve open between the two chambers, the reference pressure (Pr) is recorded. That valve is then closed and the test chamber is filled with a gas to an initial pressure Pi. Helium is usually used because it can fill small pores due to its high diffusivity. Then the valve between the two chambers is opened and the final pressure within the two connected chambers becomes Pf. The volume occupied by the sample (Vsample) can be calculated as below (British Pharmacopoeia 2017, European Pharmacopoeia 2017, United States Pharmacopeia 40-National Formulary 35 2017):
Production of rice bran oil (Oryza sativa L.) microparticles by spray drying taking advantage of the technological properties of cereal co-products
Published in Journal of Microencapsulation, 2022
Nathan H. Noguera, Dyana C. Lima, José Claudio Klier Monteiro Filho, Rodney A. F. Rodrigues
To determine the bulk packed density (g.cm−3), 2.00 g of powder was transferred to a 25 ml graduated cylinder and accommodated by successive beats until there was no more variation in volume. Then, the packed bulk density was calculated through the relation between the mass of the particles and the volume occupied by them. This parameter considers the existence of empty spaces between the particles. The real density, which considers only the mass and volume occupied by each particle, was evaluated at 25 °C in an AccuPyc® 1330 V2.02 2399 automatic helium gas pycnometer (Norcross, USA). The particle bed porosity (%) was calculated through the relation between the packed bulk density and the real density of the particles (Koç et al. 2008).
Impact of roll compaction design, process parameters, and material deformation behaviour on ribbon relative density
Published in Drug Development and Industrial Pharmacy, 2018
Kitti Csordas, Raphael Wiedey, Peter Kleinebudde
Apparent particle density. The apparent particle density of the studied materials was measured using helium gas pycnometer (AccuPyc 1330, Micromeritics, Norcross, GA, USA). Each bulk powder was measured n = 3 and 10 measuring cycles were set during each measurement. The average apparent particle density of MCC was measured to be 1.5712 g/cm3, for spray-dried mannitol 1.4715 g/cm3 and in case of the 50–50% (w/w) mixture 1.5424 g/cm3.
Parameter estimation for roller compaction process using an instrumented vector TF mini roller compactor
Published in Pharmaceutical Development and Technology, 2019
Jay Poorna Reddy, Rahul Phanse, Vishwas Nesarikar
Ribbons collected from roller compaction were analyzed for relative density values. True density of pre-blends and envelope density is required for calculation of relative density. True density of pre-blends measured by Accupyc II 1340 Helium Gas Pycnometer (Micromeritics Instrument Co., Norcross, GA, USA). Analysis was conducted in triplicate. The pre-blend samples were dried at 50 °C for 12 h prior to analysis.