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Biomedical subjects

K K Sirkar

Publications and source records attributed to K K Sirkar.

5 recordsLinked to original sources
PubMed2001

Mathematical model of a hybrid dispersed network-membrane-based controlled release system.

A mathematical model with an exact solution is presented for the controlled release of a drug from a hybrid dispersed network-membrane based system. Both hollow fiber and flat membrane device geometries are considered. The reservoir is loaded with a drug dispersed in a liquid phase. This reservoir is bounded by a microporous membrane, the pores of which are filled with liquid immiscible with the reservoir phase liquid. The drug dissolves from the solid network into the reservoir liquid and migrates through the reservoir toward the microporous membrane. At the interface between the reservoir and the pore, the solute partitions between the reservoir and the pore liquid phases, before diffusing outward through the membrane pore. Experimental results are in close agreement with the release profiles predicted by the mathematical model. Parametric studies reveal the interaction between system parameters and the controlled release behavior. The presence of a dispersed drug phase in the reservoir results in the release of drug for an extended time. The release rate of the drug may be controlled by its rate of diffusion through the membrane pores or by its rate of dissolution into the reservoir liquid.

Chemistry, Pharmaceutical↗
PubMed1999

A mathematical model of an aqueous-organic partition-based controlled release system using microporous membranes.

A mathematical model with an exact solution is presented for the membrane-controlled release of small molecules such as nicotine, caffeine, and benzoic acid initially present in solution in the reservoir of the device. Both hollow fiber and flat membrane device geometries are considered. The reservoir is bounded by a microporous membrane, the pores of which are filled with a pore liquid immiscible with the reservoir phase liquid. At the interface between the reservoir and the pore, the solute partitions between the reservoir and the pore liquid phases, before diffusing outward through the membrane pore. The model results compare well with experimental data. Parametric studies reveal the interaction between system parameters and the controlled release behavior. A high partition coefficient of the solute between the reservoir and pore phases is found to effect pseudo-zero order release for an extended time. Similarly, when the ratio of time constants for transport of the solute through the reservoir and membrane regions is small, a constant release rate is achieved for an extended time.

Benzoic Acid↗
PubMedDate not supplied

Pressure and flux profiles in bead-filled ultrafiltration/microfiltration hollow fiber membrane modules.

A general mathematical model for the prediction of pressure, flow rate, and flux profiles in an ultrafiltration/microfiltration hollow fiber membrane module whose shell side is filled with beads has been developed. The model was studied for a variety of operational modes in such modules, e.g., ultrafiltration/microfiltration, permeate flow rate control, Starling flow (encountered in hollow fiber bioreactors), and tube-side elution (encountered in filtration-cum-chromatography processes), etc., with or without a bead-filled extended section at the permeate outlet. An algorithm is provided to determine the model parameters from experimental data using the model equations. The solutions developed have been used to study the uniformity of transmembrane pressure profile along the module length using a quantity called the uniformity factor alpha. This factor shows that the model can be a useful tool for achieving the desired module performance in a number of quite different applications. The model predicts successfully the nature of the transmembrane pressure profile and the solvent flux profile in situations that are quite different, namely, conventional ultrafiltration and Starling flow. The approach used in this study can also be adopted to develop a model for description of other operational modes such as backflushing and shell-side elution used in the processes of filtration-cum-chromatography. Those applications employing similar device configurations may also use this model to predict the pressure and flux profiles to facilitate the design of the process and the operation conditions.

Membranes, Artificial↗
PubMedDate not supplied

An integrated process for biomolecule isolation and purification.

Biomolecule isolation and purification from a fermentation broth usually involve centrifugation, filtration, adsorption, and chromatography steps. Each step contributes to the product cost and product loss. In this research, a cyclic process integrating commercially available ultrafiltration membranes and chromatographic resin beads was developed to achieve the same goal in one device. The device consisted of ion exchange beads on the shell side of a hollow fiber ultrafiltration module. Loading of proteins on the stationary phase on the shell side was carried out for a period of 5-20 min from the permeate on the shell side produced from tube-side feed in ultrafiltration. The eluent was then introduced either from the shell-side inlet or tube-side inlet; the chromatographic fractions were collected from the shell-side outlet. The column was regenerated/washed next to start a new cycle. Systems studied in this cyclic process include the following binary mixtures: myoglobin and beta-lactoglobulin; hemoglobin and bovine serum albumin; and myoglobin and alpha-lactalbumin. Excellent resolutions of the proteins were obtained. A yeast-based cellular suspension containing a mixture of myoglobin and alpha-lactalbumin was also applied to this device. The target proteins were recovered and purified successfully. The cyclic process-based device integrates clarification, concentration, and chromatographic purification of biomolecules and is suitable for both extracellular and intracellular products.

Animals↗