LHRH flux

In a separate experiment, the LHRH flux was measured for 24hr during and following electrotreatment. The results (Fig. 5) were obtained using a direct current ofO.SOmA/cm for 1 h, with or without an exponential pulse (500-V initial amplitude and 6.7-msec time constant). The results again showed a significant increase in LHRH flux following the application of an electrical pulse. Moreover, the flux decreased after treatment to values near that obtained prior to electrotreatment, or in the absence of a pulse. 

Figure 6. The iontophoretic LHRH flux through human skin as a function of current density in the absence (O) or presence ( ) of an electroporative pulse.

Fig. 7 Transport of LHRH (mean SD) across human epidermis in vitro. A) passive flux, B) transport after 30 min of iontophoresis at 0.5mA/cm D) transport after a single electroporative pulse (1000 V, 5 msec) followed by 30 min of iontophoresis at 0.5mA/cm. The passive fluxes 2h after termination of treatments B and D (columns C and E, respectively) are also shown. (Redrawn from data in Ref. l)...

The delivery of LHRH through human skin in vitro was measured before, during, and alter the application of direct current (0.5 mA/cm for 30 min), either without or with (Fig. 3) a single exponential electrical pulse, applied at the initiation of the direct-current treatment (Bommannan et al, 1994). Prior to electrical treatment, the passive flux of LHRH was near 0.05 g/(cm2. hr) for both pulsed and nonpulsed samples. The application of... 

A plot of the LHRH transport data (Fig. 4a,b) shows a linear dependence of flux upon current density for both treatment protocols (Fig. 6). The flux of an ionic peptide (J ) of charge Z, through skin is related to the applied current (i) by... 

Similar to the results obtained with LHRH, calcitonin flux increased linearly with applied current in the presence or absence of an electical pulse (data not shown). Electrical pulsation, however, resulted in about 2-fold greater flux at each current density tested. From a linear regression analysis... 

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