Reflectometric monitoring of the dissolution process of thin polymeric films.
Pharmaceutical thin films are versatile drug-delivery platforms i.e. allowing transdermal, oral, sublingual and buccal administration. However, dissolution testing of thin films is challenging since the commonly used dissolution tests for conventional dosage forms correspond rather poorly to the physiological conditions at the site of administration. Here we introduce a traditional optical reflection method for monitoring the dissolution behavior of thin polymeric films. The substances, e.g. drug molecules, released from the film generate an increase in the refractive index in the liquid medium which can be detected by reflectance monitoring. Thin EUDRAGIT®RL PO poly(ethyl acrylate-co-methyl methacrylate-co trimethylammonioethyl methacrylate chloride) (RLPO) films containing the model drug perphenazine (PPZ) were prepared by spraying on a glass substrate. The glass substrates were placed inside the flow cell in the reflectometer which was then filled with phosphate buffer solution. Dissolution was monitored by measuring the reflectance of the buffer liquid. The method was able to detect the distinctive dissolution characteristics of different film formulations and measured relatively small drug concentrations. In conclusion, it was demonstrated that a traditional optical reflection method can provide valuable information about the dissolution characteristics of thin polymeric films in low liquid volume surroundings.
School of Pharmacy, University of Eastern Finland, P.O. Box 1627, FI-70211 Kuopio, Finland. Electronic address: riikka.laitinen@uef.fi.
Riikka
R
Laitinen
Unit of Measurement Technology, MITY, Technology Park P.O. Box 127, FI-87400 Kajaani, Finland.
Jukka
J
Räty
School of Pharmacy, University of Eastern Finland, P.O. Box 1627, FI-70211 Kuopio, Finland.
Kristiina
K
Korhonen
School of Pharmacy, University of Eastern Finland, P.O. Box 1627, FI-70211 Kuopio, Finland.
Jarkko
J
Ketolainen
Institute of Photonics, University of Eastern Finland, P.O. Box 111, FI-80101 Joensuu, Finland.
Kai-Erik
KE
Peiponen
D016503:Drug Delivery Systems; D065546:Drug Liberation; D008689:Methacrylates / Q000737:chemistry*; D055095:Optics and Photonics / Q000295:instrumentation*; D010546:Perphenazine / Q000737:chemistry; D012995:Solubility
D008689:Methacrylates; D010546:Perphenazine
Dissolution; Internal reflection; Monitoring; Reflectometry; Refractive index; Thin film