The influence of native and acid-modified sweet potato (Ipomoea batatas) starches on the buoyancy, mechanical and release properties of floating bilayer tablets of ambroxol hydrochloride

• Published in: Journal of excipients and food chemicals Vol. 13; no. 2
• Main Author: Adenike Okunlola
• Format: Journal Article
• Language: English
• Published: International Pharmaceutical Excipients Council 01.06.2022
• ISSN: 2150-2668

Ambroxol hydrochloride is a mucolytic agent administered orally 2 to 3 times daily because of its short half-life. A formulation of a floating bilayer tablet of ambroxol hydrochloride with immediate and sustained release layers for once- daily administration will prolong drug retention time, increase absorption and increasee patient compliance. Thus, the aim of this study was to design floating bilayer tablets of ambroxol hydrochloride using sodium starch glycolate, SSG, as the immediate release polymer (4.0% w/w) and native and acid-modified sweet potato starches as sustained release polymers (5.0, 7.5 and 10.0 % w/w) comparing with HPMC K15M as standard. A 3 X 2 factorial design was employed to evaluate the influence of polymer type and polymer concentration on buoyancy, mechanical and release properties of the tablets. Native and modified starches were characterized using SEM, FTIR, swelling and flow properties. Buoyancy characteristics of the tablets were evaluated using floating lag time and total floating time. Mechanical properties were evaluated using crushing strength and friability, while the release properties were evaluated using disintegration and dissolution times. SEM showed an increase in starch particle size and distortion in shape on acid-modification while FTIR revealed distinct differences in the spectra. The bilayer tablets containing the acid modified sweet potato starch had the highest total floating time, crushing strength, disintegration and dissolution times compared with those containing native starch and HPMC. Polymer type had greater influence on total floating time, crushing strength (p=0.001), disintegration time and dissolution time (p =0.003) while polymer concentration influenced floating lag time and friability (p>0.05). Optimized formulations exhibiting prolonged buoyancy, high mechanical strength and sustained drug release was obtained with acid-modified sweet potato starch at polymer concentration of 10% w/w. Acid-modified sweet potato starch may provide a suitable polymer for the formulation of floating bilayer tablets for prolonged buoyancy, sustained release, reduction in dose and dosing frequency.