Pharmaceutical Research

, Volume 31, Issue 8, pp 2140–2151

Evaluation of Coating Properties of Enteric-Coated Tablets Using Terahertz Pulsed Imaging

Research Paper

ABSTRACT

Purpose

Enteric coatings are used to reduce gastrointestinal side effects and control the release properties of oral medications. Although widely used, the effect of formulation and process conditions on physicochemical and functional properties of enteric coatings remains unclear.

Methods

Terahertz pulsed imaging (TPI) was employed to evaluate the coat properties of enteric coated tablets (ECTs) with various acid resistance. Other analytic methods, such as loss on drying, scanning electron microscopy and X-ray computed tomography were then used to validate the relationships established among 4 TPI-derived parameters and the physicochemical properties of enteric coatings.

Results

Weight gain measurement did not provide any information to assess acid resistance of enteric coating, whereas four TPI-derived parameters non-destructively reflected the coating properties such as thickness, coat uniformity, density, and water distribution, allowing the identification of the causes of poor acid resistance in certain ECT batches using a single measurement. These parameters also revealed the effect of coating conditions; in particular, coating under dry conditions led to less dense and nonuniform coatings with poor acid resistance.

Conclusion

We demonstrated the utility of TPI to identify structural defects within ECTs with poor acid resistance. TPI-derived parameters can aid in formulation development and quality control of ECTs.

KEY WORDS

acid uptake coating uniformity enteric coated tablets terahertz pulsed imaging X-ray CT scan 

ABBREVIATIONS

ANOVA

Analysis of variance

API

Active pharmaceutical ingredient

ECT

Enteric coated tablet

LOD

Loss on drying

MFT

Minimum film forming temperature

NIR

Near infrared spectroscopy

SEM

Scanning electron microscopy

TEFPS

Terahertz electric field peak strength

TPI

Terahertz pulsed imaging

XRCT

X-ray computed tomography

Copyright information

© Springer Science+Business Media New York 2014

Authors and Affiliations

  1. 1.Pharmaceutical Technology R&D Laboratories; CMC CenterTakeda Pharmaceutical Company Ltd.OsakaJapan
  2. 2.Faculty of Pharmaceutical SciencesToho UniversityFunabashiJapan

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