TRANSDERMAL SYSTEM EXPLAINED
ELECTROPORATION EXPLAINED
SIMILDIET LABORATORIOS - TRANSDERMAL SYSTEM MACHINE - LUIGCO 700 (instruction manual)

ELECTROPORATION

Another form of iontophoresis is electroporation . This process, in which brief, intense electric charges create small pores in the phospholipid bilayer of cell membranes, can also assist in the transdermal delivery of drugs. Electroporation appears to disrupt the lipid bilayers in the stratum corneum, and the channels it creates are said to promote the passage of hydrophilic drugs through the skin. Skin hydration increases, skin resistance decreases, and cutaneous blood flow increases (transiently). These changes have been shown to be reversible. In the future, electroporation may facilitate the delivery of hydrophilic drugs that are poor candidates for more traditional transdermal drug delivery.

Electroporation: This method involves the application of high voltage pulses to the skin which has been suggested to induce the formation of transient pores. High voltages (Ž100 V) and short treatment durations (milliseconds) are most frequently employed. Other electrical parameters that affect delivery include pulse properties such as waveform, rate and number (Banga et al, 1999). The technology has been successfully used to enhance the skin permeability of molecules with differing lipophilicity and size (i.e. small molecules, proteins, peptides and oligonucleotides) including biopharmaceuticals with molecular weights greater that 7kDA.

As electroporation improves the diffusion of such a wide range of compounds, it is thought that the pores created in the superficial layers of the skin are directly responsible for the increase in skin permeability (Weaver et al, 1999).

Electroporation is the creation of transient aqueous pores in lipid bilayer membranes by the application of a short (msec) electric pulse (Prausnitz M R et al. Proc Int Symp Control. Rel Biact Mater 1993; 20: 95-96). By using electroporation the skin permeability will be altered such that resistance to drug transport is reduced. Electroporation has been employed in transdermal drug delivery by coupling it with iontophoresis (Bommannan D et al. Pharm Res 1994; 11: 1809-1814, Prausnitz M R et al. Proc Na Acad Sci USA 1993; 90: 10504-10508, and Riviere J E et al. J Controlled Release 1995; 36: 299-233). In these cases, a short (few milliseconds) pulse of high voltage alters the skin permeability such that subsequent iontophoresis is facilitated.

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