Passive Diffusion

(NOTE: You will have to change the results for passive diffusion: it just does not occur with lidocaine, according to all previously published results. I suggest you keep all absorbance readings below 0.006, and we will say any transport was due to artifact or experimental error.) Use results for passive diffusion and iontophoresis as obtained shown on same plot. For example:

Figure 1 shows the absorbance over the time course for the transportation of lidocaine from the donor compartment to the receptor compartment under conditions of passive diffusion: Figure 2 shows the absorbance over the time course for the transport of lidocaine from the donor compartment to the receptor compartment when an electrical current of 0.02mA was applied. There was very little passive diffusion of the lidocaine across the cellophane membrane. When a current was applied, the lidocaine concentration accumulated in the receptor compartment in a time-dependent manner. The cumulative transportation of lidocaine to the receptor compartment under conditions of passive diffusion can be seen in Table 1. The cumulative transportation of lidocaine to the receptor compartment under iontophoretic conditions can be seen in Table 2.

A roughly linear relationship was achieved for iontophoretic transfer of

Related Essays

A creatinine molecule .... to function. Passive transport is by simple diffusion down a concentration gradient, and requires no energy input. It occurs because .... (3173 13 )

The abuse of Siblings: A case study proposal .... to recognize them and use them clinically First line intrusion, diffusion and suffusion .... often tend to view people as either active or passive in interactions .... (3445 14 )

The Blood-Brain Barrier The Blood-Brain Barrier .... Small water-soluble molecules appear to pass by simple diffusion into the .... In normal brain, complex tight junctions impose a passive, nonselective obstruction .... (2052 8 )

The Digestive System .... absorption (except fructose, which moves by facilitated diffusion) to blood capillaries (347) b fatty acids (long chain) and glycerol - passive absorption to .... (1830 7 )

Selection of School Superintendents .... thus, play a special role in society in the development and diffusion of values .... from rules and standards to take corrective action) or passive (intervening only .... (5454 22 )

value. From the results obtained, they concluded that permeation kinetics across skin were not linear but the patch acted as a matrix controlling drug delivery and the permeation rate increased with drug loading (Padula et al 277-285). The in vivo experiments indicated that the presence of water during tape application was essential to achieve the proper adhesion and to allow effective accumulation of the drug. Applying an electric current to the tape increased the amount of drug which accumulated in the stratum corneum, indicating that lidocaine can be delivered through the skin using bioadhesive films. Sing and Roberts (127-131) used iontophoretic transdermal delivery of salicylic acid and lidocaine to local subcutaneous structures and evaluated the depth of penetration into underlying tissues. The levels of the two drugs were measured in plasma and in tissues below the electrodes of rats who had received them through iontophoresis. These levels were compared to those obtained with passive delivery (no iontophoresis) either to intact epidermis or to exposed dermis. Iontophoresis resulted in high concentrations of lidocaine in underlying tissues in both conditions compared to passive diffusion. Negligible c

Category: Misc - P