Two important interfacial properties of suspensions are: The surface free energy, and The presence of electric charges on the surface of the dispersed particles. Surface Free Energy When solid or liquid materials are reduced in size, the surface area increases readily leading to corresponding increase in surface free energy given by: ΔF ∝ ΔA ΔA
Interfacial Properties of Suspended Particles Read More »
Flocculated and deflocculated suspension: The solid drug is crushed into smaller particles and then dispersed in a dispersion medium in order to prepare a suspension. As a result of crushing, the surface area of particles and their associated surface free energy increases. This makes the system thermodynamically unstable with highly energetic particles which regroup and
Flocculated and Deflocculated Suspensions Read More »
The dispersion system is categorised in the following three groups based on the size of dispersed particles: Molecular Dispersion: This system behaves as true solutions where the solute phase is present in the solvent phase. The solute (dispersed phase) is homogeneously distributed as separate molecules of size below 1nm (10-7 cm) throughout the solvent (dispersion
Classification of Dispersed Systems and Their General Characteristics Read More »
Industrial fermenter are either of anaerobic or aerobic classes. Anaerobic fermenters do not require much special equipment, except for the removal of heat generated during the fermentation process; on the contrary, aerobic fermenters require much elaborate equipment for adequate mixing and aeration. The industrial fermentation processes are mostly aerobic, thus a typical aerobic fermenter is
Large Scale Production Fermenter Design Read More »
E.M. Southern invented the technique of southern blotting. This method is useful in molecular biology. In this method, hybridisation analysis is performed by transferring the DNA from a gel to a membrane. The DNA is cleaved using suitable restriction enzymes and made to run on a gel. Then it is treated with sodium hydroxide that
Southern Blotting – Pedagogy Zone Read More »
ELISA is a solid-phase enzyme immunobinding assay, and the most essential of the immune-enzyme assays. In this method, the antigen is attached to an antibody anchored on a solid phase (polystyrene or polyvinylchloride). This helps in retaining the immunological as well as the enzymatic activity. ELISA can be used for quantitating antibody or antigen using
Enzyme Linked Immunosorbent Assay (ELISA) Read More »
The method of western blot was discovered by George Stark at Stanford, and the name western blot was laid down by W. Neal Burnette. This method, also known as immunoblot or protein blot, detects specific proteins in a sample of tissue homogenate or extract. Western blotting is a qualitative and semi-quantitative technique for protein analysis.
Western Blotting – Pedagogy Zone Read More »
The desired antibodies should be extracted from a media sample of cultured hybridomas or a sample of ascites fluid. The contaminants in the cell culture sample consists of growth factors, hormones, and transferrins. The in vivo sample however, contains host antibodies, proteases, nucleases, nucleic acids, and viruses. Other secretions by the hybridomas (like cytokines) may
Purification of MAbs – Pedagogy Zone Read More »
Production of MAbs in culture bottles is low (5−10μg/ml), thus to increase the yield the hybrid cells are grown as ascites in the peritoneal cavity of mice. The ascitic fluid contains 5−20mg of MAb/ml, which is much superior to the in vitro cultivation techniques. Collection of MAbs from ascitic fluid has a heavy risk of contamination by pathogenic
Large Scale Production of MAbs Read More »
Many biological preparation become unstable during storage and thus their safety and efficacy are reduced. Proteins and other macromolecules may be sensitive to heat, light, radiation, and environmental changes, or they may interact with the container materials or other components of the vaccine mixture. Determining these relationships and optimising stability from the time of production
Storage Conditions and Stability of Official Vaccines Read More »