Contributors to Volume 19Contents of Other VolumesBlow-Fill-Seal Aseptic ProcessingDeborah J. JonesCompounding, ContemporaryLoyd V. Allen, Jr.Drug Delivery-Oral Colon SpecificVincent H. L. Lee and Suman K. MukherjeeThe European Agency for the Evaluation of Medicinal Product (EMEA)David JacobsHarmonization-CompendiaLee. T. Grady and Jerome A. HalperinInhalation, Dry PowderLynn Van Campen and Geraldine VenthoyeLiquid Crystals in Drug DeliveryChristel C. Mueller-GoymannMedication Errors: A New Challenge for the Pharmaceutical IndustryDiane R. CousinsMucoadhesive Hydrogels in Drug DeliveryHans E. Junginger, Maya Thanou, and J. Coos VerhoefPeptides and Proteins: Buccal AbsorptionHemant H. Alur, and Thomas P. Johnston, and Ashim K. MitraPharmaceutical Quality Assurance Microbiology LaboratoriesAnthony M. CundellProcess Chemistry in the Pharmaceutical IndustryKumar G. Gadamasetti and Ambarish K. SinghRadiolabeling of Pharmaceutical Aerosols and Gamma Scintigraphic Imaging for Lung DepositionHak-Kim ChanSuper Disintegrants: Characterization and FunctionLarry L. Augsburger, Albert W. Brzeczko, Umang Shah, and Huijeong A. HahmIndex to Volume 20

Encyclopedia of Pharmaceutical Technology

High-throughput crystallization: polymorphs, salts, co-crystals and solvates of pharmaceutical solids

Nanocrystalline cellulose (NCC) is an emerging renewable nanomaterial that holds promise in many different applications, such as in personal care, chemicals, foods, pharmaceuticals, etc. By appropriate modification of NCC, various functional nanomaterials with outstanding properties, or significantly improved physical, chemical, biological, as well as electronic properties can be developed. The nanoparticles are stabilised in aqueous suspension by negative charges on the surface, which are produced during the acid hydrolysis process. NCC suspensions can form a chiral nematic ordered phase beyond a critical concentration, i.e. NCC suspensions transform from an isotropic to an anisotropic chiral nematic liquid crystalline phase. Due to its nanoscale dimension and intrinsic physicochemical properties, NCC is a promising renewable biomaterial that can be used as a reinforcing component in high performance nanocomposites. Many new nanocomposite materials with attractive properties were obtained by the physical incorporation of NCC into a natural or synthetic polymeric matrix. Simple chemical modification on NCC surface can improve its dispersability in different solvents and expand its utilisation in nano-related applications, such as drug delivery, protein immobilisation, and inorganic reaction template. This review paper provides an overview on this emerging nanomaterial, focusing on the surface modification, properties and applications of NCC.

Chemistry and Applications of Nanocrystalline Cellulose and its Derivatives: a Nanotechnology Perspective

Drug polymorphism and dosage form design: a practical perspective.

The mechanical properties of hybrid framework materials, including both nanoporous metal–organic frameworks (MOFs) and dense inorganic–organic frameworks, are discussed in this critical review. Although there are relatively few studies of this kind in the literature, major recent advances in this area are beginning to shed light on the fundamental structure–mechanical property relationships. Indeed research into the mechanical behavior of this important new class of solid-state materials is central to the design and optimal performance of a multitude of technological applications envisaged. In this review, we examine the elasticity of hybrid frameworks by considering their Young's modulus, Poisson's ratio, bulk modulus and shear modulus. This is followed by discussions of their hardness, plasticity, yield strength and fracture behavior. Our focus is on both experimental and computational approaches. Experimental work on single crystals and amorphized monoliths involved primarily the application of nanoindentation and atomic force microscopy to determine the elastic moduli and hardness properties. The compressibility and bulk moduli of single crystals and polycrystalline powders were studied by high-pressure X-ray crystallography in the diamond anvil cell, while in one instance spectroscopic ellipsometry has also been used to estimate the elastic moduli of MOF nanoparticles and deposited films. Theoretical studies, on the other hand, encompassed the application of first principles density-functional calculations and finite-temperature molecular dynamics simulations. Finally, by virtue of the diverse mechanical properties achievable in hybrid framework materials, we propose that a new domain be established in the materials selection map to define this emerging class of materials (137 references).

Mechanical properties of hybrid inorganic–organic framework materials: establishing fundamental structure–property relationships

The use of solubility parameters in pharmaceutical dosage form design

Sulfathiazole, a compound that forms four known crystal structures, has been examined with a view to understanding its polymorphism. A graph set approach was used to classify the structural differences and similarities of the polymorphs, the results of which indicated packing motifs common to three of the four structures. By combining this analysis with experimental morphological data, it has been possible to examine the origins of the observed solvent dependence of polymorph appearance in this system. In particular, the possible link between the observed hydrogen-bond motifs of each form and the associated processes of nucleation and crystal growth from n-propanol, nitromethane, ethanol, water and ammonia solution, have been considered.

Crystal chemistry and solvent effects in polymorphic systems Sulfathiazole

The interaction between water and microcrystalline cellulose in the absence and presence of lactose has been studied by thermogravimetric analysis, differential thermal analysis and immersional calorimetry. The results indicate that most of the water held within a system used for the preparation of spherical granules by extrusion/spheronization is present as free water which may be readily lost by evaporation. There is approximately 0.856 mol of water per 100 g of microcrystalline cellulose which appears to be absorbed as structured water. Microcrystalline cellulose may therefore be described as a 'molecular sponge'. The enthalpy of fusion of the 'free' water offers a simple method of estimating the effective surface area of the microcrystalline cellulose.

Raymond C Rowe

Papers

The use of solubility parameters in pharmaceutical dosage form design

Crystal chemistry and solvent effects in polymorphic systems Sulfathiazole

Thermal Studies on the Interaction of Water and Microcrystalline Cellulose

The relationship between Young's modulus of elasticity of organic solids and their molecular structure

Determination of the surface properties of two batches of salbutamol sulphate by inverse gas chromatography