ABSTRACT
Colloids are a dispersion of one phase to another, and its size ranges from 1 nm to 1 µm, and in a system, discontinuities are found at distances of that order. These nanoscale dispersed systems have considerable application in drug delivery and formulation methods.1,2 Understanding the properties of colloids can be used as a tool to access rational criteria for formulation development. Colloidal properties provide an idea about absorption, cell membrane interaction, and drug molecule behavior in the surrounding environment. Such properties play a major role in drug-loading capacity and transport mechanisms as charge and colloidal size ranges are set for this capacity. The colloidal particles greatly affect the rate of sedimentation, osmotic pressure as well as the stability and biocompatibility of colloidal drug carrier. The colloidal properties also provide a selection basis for excipients and manufacturing process criteria. These properties include the particle properties studied by the Tyndall effect, turbidity, and dynamic light scattering. Optical properties are widely used to observe the size, shape, and structure of colloidal particles. The kinetic properties, which include Brownian motion, diffusion, osmosis, sedimentation, and viscosity, deal with motion of particles with respect to the dispersion medium. These properties provide a detailed idea on the movement of colloidal carrier within the body as well as the transportation criteria of colloidal carrier across the cell membrane. The physicochemical properties such as physical state, lyophilicity, and lyophobicity are helpful in the selection of colloidal carrier for a particular drug delivery. Electrical properties, which include electrical conductivity and surface charges, are related with migration of particle and give an idea about the selection basis for excipients and the interaction of colloidal carrier with a cell membrane. The magnetic
48.1 Colloids..............................................................................................................................1111 48.2 Micelles.............................................................................................................................1112 48.3 Dendrimers ........................................................................................................................1114 48.4Liquid Crystals..................................................................................................................1114 48.5Cubosomes and Hexosomes ..............................................................................................1115 48.6 Gels ....................................................................................................................................1116 48.7 Emulsions ..........................................................................................................................1116 48.8Multiple Emulsions............................................................................................................1117 48.9 Nanoemulsions ..................................................................................................................1117 48.10 Microemulsions .................................................................................................................1117 48.11 Liposomes .........................................................................................................................1118 48.12 Niosomes ...........................................................................................................................1119 48.13 Polymersomes................................................................................................................... 1120 48.14 Nanocapsules .................................................................................................................... 1120 48.15 Microspheres .....................................................................................................................1121 48.16 Aerosols .............................................................................................................................1121 48.17 Foams ............................................................................................................................... 1122 References .................................................................................................................................... 1122
properties of colloids deal with specic delivery of drug inside the body, which helps to increase the efcacy of drug and reduces the toxicity.
