The Interplay between Drug and Sorbitol Contents Determines the Mechanical and Swelling Properties of Potential Rice Starch Films for Buccal Drug Delivery.

Bilal Harieth Alrimawi,Siok-Yee Chan,Xin Yue Ooi,Choon Fu Goh,May Yee Chan

doi:10.3390/polym13040578

Abstract

Rice starch is a promising biomaterial for thin film development in buccal drug delivery, but the plasticisation and antiplasticisation phenomena from both plasticisers and drugs on the performance of rice starch films are not well understood. This study aims to elucidate the competing effects of sorbitol (plasticiser) and drug (antiplasticiser) on the physicochemical characteristics of rice starch films containing low paracetamol content. Rice starch films were prepared with different sorbitol (10, 20 and 30% w/w) and paracetamol contents (0, 1 and 2% w/w) using the film casting method and were characterised especially for drug release, swelling and mechanical properties. Sorbitol showed a typical plasticising effect on the control rice starch films by increasing film flexibility and by reducing swelling behaviour. The presence of drugs, however, modified both the mechanical and swelling properties by exerting an antiplasticisation effect. This antiplasticisation action was found to be significant at a low sorbitol level or a high drug content. FTIR investigations supported the antiplasticisation action of paracetamol through the disturbance of sorbitol–starch interactions. Despite this difference, an immediate drug release was generally obtained. This study highlights the interplay between plasticiser and drug in influencing the mechanical and swelling characteristics of rice starch films at varying concentrations.

Highlights

In recent years, advances in thin film technology have broadened the repertoire for drug delivery, especially through the buccal route [1,2,3,4]
This result is consistent with the report by Laohakunjit and Noomhorm [43], who reported that rice starch film thickness was increased by the addition of sorbitol
While sorbitol plasticisation on starch films is well known, this study provides an in-depth understanding of the influence of PCM on modifying the typical plasticising role of sorbitol in rice starch films

Summary

Introduction

Advances in thin film technology have broadened the repertoire for drug delivery, especially through the buccal route [1,2,3,4]. An ideal film for buccal drug delivery should facilitate the drug release and absorption [5]. The films should possess adequate flexibility and strength in order to tolerate stress upon application into the buccal cavity and to achieve a desired drug release [6,7,8]. The flexibility and strength of buccal films are immensely affected by the type of film-forming agents used, which are usually polymers [9]. The key characteristics of buccal films including drug release profiles, mucoadhesive properties and mechanical strength can be governed by adjusting the composition of polymers [10]. The formation of films from biomaterials such as starch and proteins as a film-forming agent usually requires a plasticiser [14]. Plasticisers are necessary to overcome film brittleness owing to the high polymer intermolecular forces [15]

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