Starch Film as a Carrier of a Model Drug Substance from the Group of Non-Steroidal Anti-Inflammatory Drugs

Abstract

The article describes the production of starch film as a carrier of a model drug substance from the group of non-steroidal anti-inflammatory drugs (NSAIDs). An analgesic/anti- inflammatory drug was put into aqueous starch solution, and next a film was formed. The following solid drug substances were included in the tests: acetylsalicylic acid, salicylic acid, ibuprofen lysine salt, naproxen in the form of acid, and sodium salt. Solutions were obtained from ibuprofen lysine salt and naproxen sodium, whereas the other drugs enabled to obtain aqueous suspensions. Such a drug substance was mixed with aqueous starch solution to obtain a film. Forming a film under laboratory conditions involved spreading aqueous starch solution containing a drug on a flat heated surface and evaporating water. The films obtained were transparent. They were then dried for a period of 24 hours at a temperature of 20 °C and 50% relative air humidity. Next their mechanical properties were studied. Starch films which contained therapeutic substances were characterised by Fourier transform infrared spectroscopy (FTIR). There were slight differences between the spectra of films containing a drug substance and those of films containing both starch and a drug substance, which implies weak intermolecular reactions. Scanning electron microscope (SEM) images of cross-sections of the starch films with a drug substance were taken, which indicated their uniform morphological structure. The release rate of the drug from each film to an acetate buffer pH 4.5 (acetylsalicylic acid and salicylic acid) or phosphate buffer pH 7.38 (ibuprofen lysine salt and naproxen) was determined in vitro with the paddle method. This procedure took up to 90 min. Acetylsalicylic acid and salicylic acid were almost completely released from the starch film as early as in the first minutes of the procedure, with a maximum value of around 90%. The release of ibuprofen lysine salt and naproxen in the form of acid from the starch film was partial, about 40%. The release of naproxen sodium from the starch film was time-proportional, and there was a tendency towards further release.