Pharmaceutical powders

Pharmaceutical powder aerosols have more stringent requirements placed upon the formulation regarding moisture, particle size, and the valve. For metered-dose inhalers, the dispensed product must be deflvered as a spray having a relatively small (3—6 -lm) particle size so that the particles can be deposited at the proper site in the respiratory system. On the other hand, topical powders must be formulated to minimize the number of particles in the 3—6-p.m range because of the adverse effects on the body if these materials are accidently inhaled. 

Michrafy A, Ringenbacher D, Tchoreloff P. Modelling the compaction behaviour of powders Application to pharmaceutical powders. Powder Technol. 2002 127 257-66. 

Wu C-Y, Ruddy OM, Bentham AC, Hancock BC, Best SM, Elliot JA. Modelling the mechanical behaviour of pharmaceutical powders during compaction. Powder Technol 2005 152 107-17. 

Lewis RW, Gethin DT, Yang XS, Rowe RC. A combined finite-discrete element method for simulating pharmaceutical powder tableting. Int J Num Meth Eng 2005 62 853-69. 

Yang XS, Lewis RW, Gethin DT, Rowe RC. Modelling of pharmaceutical powder compaction and tableting effect of particle sizes and irregular shape. Powder Technol. 2005 in press. 

Materials that do not compress well produce soft tablets. In addition, brittle crystalline materials will yield brittle tablets. Hiestand was the first pharmaceutical scientist to quantify rationally the compaction properties of pharmaceutical powders [23-28], The results... 

Y Miyake, A Shimoda, T Jasu, M Furukawa, K Nesuji, K. Hoshi. Packing properties of pharmaceutical powders into hard gelatin capsules. Yakuzaigaku 34 32, 1974. 

P York. Application of powder failure testing equipment in assessing effect of glidants on flowability of cohesive pharmaceutical powders. J Pharm Sci 64 1216-1221, 1975. 

Pharmaceutical Powder Compaction Technology, edited by Goran Al-derborn and Christer Nystrom... 

Particle dissolution models, which presume spherical monodisperse particle size, inadequately depict the complexity of typical pharmaceutical powders. 

Ibrahim et al. [49] described a spectrophotometric method for the determination of primaquine and other antimalarial agents in pharmaceuticals. Powdered tablet or ampule contents containing 25 mg of primaquine phosphate, was dissolved in water and the solution was made alkaline with 6 M ammonia before extraction with chloroform. The extract was evaporated to dryness and the residue was dissolved in acetonitrile. A portion of the solution was mixed with 0.04% tetracyanoethylene solution in acetonitrile and diluted to volume with acetonitrile. After 10 min, the absorbance was measured at 415 nm for primaquine. Beer s law was obeyed from 2 to 12 mg/mL. The results agreed well with those of the United State Pharmacopoeia XX method. 

Consequently, we consider that the industrial scale technological management of microwave assisted chemical reaction is no compatible with batch reactors coupled with multimode applicators. Some typical processes with a systematic decrease of the dielectric losses of the concerned reactant, such as filtration and drying of mineral or pharmaceutical powders are compatible with multimode applicators. To our knowledge, the only industrial batch microwave device is the microwave variant of the Turbosphere ( all in one solution mixer/granulator/dryer designed by Moritz... 

Fig. 3 (a) A skewed size-frequency distribution typical of pharmaceutical powders, (b)... 

As an approximate method for getting an idea about the size of capsule needed, a simple rule of six is very useful. Although not very accurate, the rule of six serves as an initial guide for the capsule size selection. When the bulk density of the powdered material is 0.6 g/cc, this rule helps in obtaining the capsule size which is fairly accurate. However, since the bulk density of pharmaceutical powders is different, it is always a good idea to verify the capsule size by actually filling the material. This rule will certainly narrow down the choice of capsule size selection for initial trials. The rule of six is given below ... 

Pharmaceutical powder is a mixture of finely divided drugs and/or chemicals in dry form. They are dispensed as bulk powders or divided powders. When the prescription is received for powders, first determine whether it is based upon one unit or upon a bulk formula to be subdivided into individual units. Bulk powders are provided as multiple doses in a container and the patient measures the dose as instructed at the time of administration. Some examples of bulk powders include Tolnaftate Powder USP and Nystatin Topical Powder USP as antifungals, and Desitin Powder for diaper rash. Divided powders are meant to be provided as single dose units in individually wrapped powder papers. Such single dose packets are stacked in a powder box, and the label... 

Rowe, R. C., Roberts, R. J. Mechanical properties. In G. Alderbom, C. Nystrom (Editors), Pharmaceutical Powder Compaction Technology, Marcel Dekker, New York, pp. 283-322. 

The DustGun aerosol generator, which has been reported for the delivery of aerosol particles to the IPL for toxicological evaluations [36], is another delivery technique which could be utilised for the evaluation of drug disposition after the delivery of pharmaceutical powder aerosols to the IPL. 

Hancock et al.63 reported a comprehensive review of a wide variety of pharmaceutical powders. Investigation of electrostatic properties of the drug substance or drug-excipient mixtures during preformulation has been recommended.64 Such studies may be particularly relevant for dry powder inhalation systems. 

Hancock, B.C., Colvin, J.T., Mullarney, M.P., and Zinchuk, A.V., The relative densities of pharmaceutical powders, blends dry granulation, and immediate release tablets, Pharm. Technol., 4, 64, 2003. 

Rowley, G., Quantifying electrostatic interactions in pharmaceutical powder systems, Int. ]. Pharm., 227, 47, 2001. 

M. Lopez-Sanchez, M.J. Ruedas-Rama, A. Ruiz-Medina, A. Molina-Diaz and M.J. Ayora-Canada, Pharmaceutical powders analysis using FT-Raman spectrometry Simultaneous determination of sulfathiazole and sulfanilamide, Talanta, 74, 1603-1607 (2008). 

R. Vehring, Red-excitation dispersive Raman spectroscopy is a snitable techniqne for solid-state analysis of respirable pharmaceutical powders, Appl. Spectrosc., 59, 286-292 (2005). 

D.J. Wargo and J.K. Drennen, Near-infrared spectroscopic characterization of pharmaceutical powder blends, J. Pharm. Biomed. Anal., 14, 1415-1423 (1996). 

A.S. El-Hagrasy, F.D Amico and J.K. Drennen III, A process analytical technology approach to near-infrared process control of pharmaceutical powder blending. Part I D-optimal design for characterization of powder mixing and preliminary spectral data evaluation, J. Pharm. Sci, 95(2), 392 06 (2006). 

M.J. Barajas, A.R. Cassiana, W. Vargas, C. Conde, J. Ropero, J. Figueroa and R.J. Romanach, Near-infrared spectroscopic method for real-time monitoring of pharmaceutical powders during voiding, Appl Spectrosc., 61(5), 490-496 (2007). 

Crooks, M.J. and Schade, H.W., Fluidized bed granulation of a microdose pharmaceutical powder. Powder Tech., 19 (1978) 103-108. 

Leuenberger H. Moist agglomeration of pharmaceutical powders. In Chulia D, Deleuil M, Pourcelot Y, eds. Powder Technology and Pharmaceutical Processes, Handbook of Powder Technology. Amsterdam Elsevier, 1994 377-389. 

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