Incorporation of sulphonated cyclodextrins into polypyrrole: an approach for the electro-controlled delivering of neutral drugs.
The electro-controlled delivery of drugs based on the doping-dedoping mechanism of Electro-Conducting Polymers is restricted to charged substances acting as dopants. In order to overcome this limitation, this study presents an approach where the trapping/delivering is based on host-guest interaction. As an example of a neutral guest, the molecule N-methylphenothiazine (NMP) is encapsulated in the host, heptasulphonated beta-cyclodextrin (beta-CDSO3-), which is tailor-made to dope PPy. The original synthetic method for beta-CDSO3- is based on sulphonation of the periodated beta-CD in the phase transfer medium. As a consequence of their size and of their multicharged character, beta-CDSO3-s are fixed dopants. The stability of the beta-CDSO3- entrapment is checked by Optical Beam Deflection (mirage effect) measurements. The ionic movements associated with the switching of the beta-CDSO3- doped PPy (PPy+, beta-CDSO3-) film appear to be mainly due to cations with this technique. Cyclic voltammetry experiments confirm the entrapment of neutral NMP by simply dipping the PPy+, beta-CDSO3- film in a CH3CN solution containing NMP. Repeated electrochemical cycling of such a reservoir electrode indicates the progressive elimination of NMP from the (PPy+, beta-CDSO3- [NMP]) film.
Bidan
G
G
Laboratoire d'Electrochimie Moléculaire, Centre d'Etudes Nucléaires de Grenoble, DRFMC/SESAM, France.
Lopez
C
C
Mendes-Viegas
F
F
Vieil
E
E
Gadelle
A
A
D003505:Cyclodextrins / Q000737:chemistry*; D016503:Drug Delivery Systems / Q000379:methods*; D004553:Electric Conductivity; D004563:Electrochemistry; D010640:Phenothiazines / Q000008:administration & dosage; D011108:Polymers / Q000737:chemistry*; D011758:Pyrroles / Q000737:chemistry*; D013451:Sulfonic Acids / Q000737:chemistry*
D003505:Cyclodextrins; D010640:Phenothiazines; D011108:Polymers; D011758:Pyrroles; D013451:Sulfonic Acids; C045775:N-methylphenothiazine; C067635:polypyrrole