A pharmaceutical suspension is a coarse dispersion in which insoluble solid particles are dispersed in a liquid medium. The particles typically have diameters greater than 0.1 μm. Under a microscope, some of these particles can exhibit Brownian movement if the dispersion has low viscosity.[1] Interfacial Properties of Suspension Because suspensions are dispersions of one phase […]
Cyclodextrin (CD) is a group of compounds known as cyclic oligosaccharides. They consist of at least six D-(+)-glucopyranose units linked together by α-1,4 bonds, and are produced through the enzymatic action of Bacillus macerans amylase on starch.[1] Types and Properties of Cyclodextrin Cyclodextrins consist of 6, 7, and 8 units of glucose referred to as […]
Occlusion or inclusion complexes results more from the architecture of molecules than from their chemical affinity. One of the constituents of the complex is trapped in the open lattice or cage-like crystal structure of the other to yield a stable arrangement. Channel Lattice Type In this complex, the host component crystallizes to form a channel-like […]
Metal-ion coordination complexes, sometimes simply called metal complexes, consist of a central metal ion bonded to one or more ligands that are electron-pair donors such as a nitrogenous base (e.g., ammonia), an ion (e.g., chloride ion), or an aromatic compound (e.g., ferrocene). The number of bonds between the metal ion and the ligand or ligands […]
An organic coordination compound, or molecular complex, is composed of constituents held together by weak interactions such as donor–acceptor forces or hydrogen bonds. Molecular complexes can be classified according to: The bonding or interaction between substrate and ligand (e.g., electrostatic interaction, charge-transfer, hydrogen bonding and hydrophobic interaction). Type of substrate and ligand forming the complex […]
Complexation is a chemical process in which molecules or molecular assemblies are formed by the combination of substrates (S) and ligands (L). Most often complex (SmLn) formation is a reversible process: $$ m.S+n.L⇄S_mL_n $$ where m substrate molecules, associate with n ligand molecules to form a complex of m:n stoichiometry. In this context, complex formation, […]
The cutter mill (Fig. 1) is very similar to the hammer mill in operation, except that sharp blades are used in place of blunt surfaces. Hammer and cutter mills are especially suited for brittle or fibrous materials and can be considered the most commonly encountered mills for roller compaction (in dry granulation). Construction and Working […]
Pin mill is a method of comminution that acts by producing particle impact and attrition. Particle size reduction occurs by impaction with the pins and by attrition between pins as the particles travel outwards under the influence of centrifugal force. Construction and Working of Pin Mill Pin mills consist of two horizontal steel plates with […]