The Effect Of Crosslinking On Some Functional Properties Of Starch-Albumin Films

Builders F. Philip^1*, John E. Judith¹, Mohammed B. Boma²

¹Department of Pharmaceutical Technology & Raw Materials Development, National Institute of Pharmaceutical Research & Development, Idu, Abuja, (NIGERIA)
²Department of Pharmaceutics & Industrial Pharmacy, Faculty of Pharmaceutical Sciences, Kaduna State University, Kaduna, (NIGERIA)

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ABSTRACT – DOI: https://dx.doi.org/10.47204/EMSR.3.1.2021.010-018

Biopolymers such as starches, proteins and polyols are excellent film forming materials that produce films with good barrier, flexibility, transparency, and bio compatibility. The objectives of this study are to prepare starch-albumin films and evaluate the effect of cross-linking with formaldehyde on the physicochemical properties of the starch-albumin films as a coating material. Using glycerol as plasticizer films were prepared: starch (A), starch and albumin (B), starch-albumin cross-linked with formaldehyde at 1 % (C), 5 % (D) and 10 % (E). The thickness, thermal properties, moisture content, equilibrium swelling (ESC) in different pH media (2, 7 and 9), equilibrium relative humidity (ERH), DSC thermal properties of the films and in-vitro release of drug from tablets coated with the films were determined. Results show that cross-linking reduced the weight to thickness and moisture content of starch-albumin films. Introduction of albumin into the starch network as well as treatment with the crosslinking agent changed the characteristics of the melting transitions. The starch-albumin films also showed pH responsiveness to swelling, which was further demonstrated in the release of drug from tablets coated with the composite films. Although the films showed a controlled release of drug in both acidic (pH 1.2) and alkaline (pH 8.0) media, there was a much slower release from the alkaline medium, showing that the composite films can be utilized in the controlled drug delivery within the intestine. A new pH responsive polymer with characteristic physicochemical and thermal properties were formed when starch and albumin were co-processed and treated with formaldehyde.