Flow-through Design Research Articles

Validation of a flow-through diffusion cell for use in transdermal research.

A flow-through finite-dose diffusion cell has been designed for use in transdermal drug delivery research. The diffusion cell consists of an upper donor chamber and a lower receiver compartment through which a continuous supply of fresh solvent flows. The flow is directed to an automatic fraction collector. To validate the flow-through cell, its performance was compared directly against that of a conventional single-reservoir Franz cell. Homologous alkyl p-aminobenzoates were diffused through dimethylpolysiloxane membranes, and permeability coefficients increased with increasing chain length, reaching a plateau at the butyrate ester for both types of cells. This behavior suggests a shift from membrane-controlled diffusion to boundary layer control. Permeation of the butyrate and valerate compounds was significantly faster when the flow-through cell was used, suggesting that better mixing is obtained through the flow-through cell design. Considering the advantages offered in terms of time and labor saved through its use, the flow-through cell with automatic fraction collector appears to be a viable alternative to the conventional Franz cell.

Amperometric flow-through solid electrode detector design: performance and application in high-performance liquid chromatography for the microdetermination of antioxidants in monomers

The development of laboratory-made electrochemical detectors of simple design with a glassy carbon working electrode employed with the conventional type and microbore high-performance liquid chromatographic (HPLC) columns is reported. The dependence of the detector response and performance on the eluent flow-rate, pump pulsation, applied potential, etc., is discussed. The detectors were used for HPLC, flow injection analysis and recording of constant depolarizer flow polarogams The application of the detectors to the analysis of hydroquinone, p-methoxyphenol and phenothiazine in acrylic monomers with detection limits of 10 −7− −8mg is described