Evaluation of Pregelatinized Enset (Ensete ventricosum) Starch as a Tablet Disintegrant in Enteric Coated Acetyl Salicylic Acid Tablet
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Date
2015-04
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Addis Ababa University
Abstract
The process of aqueous coating of moisture labile drugs demands careful selection of
tablet excipients, mainly disintegrants. Although the application of pregelatinized enset
starch (PGES) as tablet disintegrant is well documented, its potential use as tablet
disintegrant in the development of moisture labile drug for aqueous coating is not well
studied. Therefore, the objective of this study is to assess its potential use as tablet
disintegrant in the development of enteric coated acetylsalicylic acid (ASA) 81 mg tablet
in comparison to other starch based disintegrants including native enset starch (ES),
sodium starch glycolate (SSG) and pregelatinized starch 1500® (PGS 1500). ASA is a
moisture-sensitive drug and can be hydrolyzed into acetic and salicylic acid when
exposed to high humidity and elevated temperature. As the coating process will subject
ASA tablets to both high temperature and humidity, it is important that the formulation
exhibit minimum interaction with the aqueous coating solution.
The study began with the development of an optimum coating technique, which can
offer the maximum mechanical and chemical stability and other pertinent tablet qualities
but minimum exposure time to the coating solution to the tablet. Then, to investigate the
effect of the type and quantity of the disintegrant on stability and other tablet attributes,
twelve different ASA 81 mg tablet formulations, containing three different levels of the
above four disintegrants, were directly compressed using microcrystalline cellulose
(MCC) as a direct compression filler and talc as a lubricant and characterized. The
tablets were then coated using enteric coating polymer Wangit L30D-55 (aqueous
dispersion of methacrylic acid-ethyl acrylate copolymers) by conventional pan coating
technique and were further characterized. Finally, the tablets were subjected to a three
month accelerated stability study conditions and the stability of the tablets was assessed
based on coat integrity, assay results and change in the level of free salicylic acid within
the formulation.
The results of the study showed that the uncoated tablets had the desired attributes
including tablet weight variation, friability, hardness, disintegration time and dissolution
time results which were well within the acceptable limits of the USP 30-NF 25 (2007)
ix
standards. Results of the three month accelerated stability study showed that tablets
formulated with sodium starch glycolate were unstable and resulted in softening and
sticking of the coat. Besides, there was a significant increase in free salicylic acid
percentage and release of drug in the acidic stage. Unlike tablets formulated with sodium
starch glycolate, tablets formulated with the pregelatinized starches, pregelatinized enset
starch and starch 1500® as disintegrants maintained their appearance and the cumulative
percent drug release in 0.1 N HCl and buffer stage. Percent free salicylic acid, assay
results and other tablet attributes unchanged except tablet hardness, which was also
within the acceptable limit. Tablets prepared with ES were stable but ES was inferior as
tablet disintegrant. Therefore, pregelatinized enset starch can be used as a better
alternative to sodium starch glycolate and as a replacement to pregelatinized starch
1500® as tablet disintegrant in those formulation that contain moisture susceptible drugs.
Key Words: Enset starch; Disintegrant; Stability; Enteric coated; Acetylsalicylic Acid;
Pregelatinized starch, Sodium starch glycolate
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Keywords
Enset starch; Disintegrant; Stability; Enteric coated; Acetylsalicylic Acid; Pregelatinized starch, Sodium starch glycolate