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Characterization of latex particles for aqueous polymeric coating by electroacoustic method
Yasuhiro Ishikawa1, Noboru Aoki, Hiroyuki Ohshima
1Pharmaceutical Research Center, Kyowa Hakko Kogyo Co. Ltd., 1188 Shimotogari, Nagaizumi-cho, Sunto-gun, Shizuoka 411-8731, Japan. yasuhiro.ishikawa@kyowa.co.jp
Colloids and Surfaces. B, Biointerfaces
|November 22, 2005
Summary
Characterizing aqueous polymeric latex dispersions using electroacoustic methods reveals key stability parameters. This research provides insights into colloidal behavior crucial for pharmaceutical coatings.
Area of Science:
- Colloid and Surface Science
- Materials Science
- Pharmaceutical Technology
Background:
- Concentrated dispersions of aqueous polymeric coatings are vital in the pharmaceutical industry.
- Acrylic polymers and cellulose derivatives are common coating materials.
- Characterizing these dispersions is essential for quality control and application.
Purpose of the Study:
- To characterize polymethacrylate-based aqueous polymeric latex dispersions (Eudragit L30D-55 and Eudragit RL30D) using electroacoustic methods.
- To evaluate the influence of volume fraction, pH, and salt concentration on dispersion properties.
- To assess colloidal stability based on electroacoustic measurements and DLVO theory.
Main Methods:
- Electroacoustic measurements, specifically Colloidal Vibration Current (CVI), were employed.
- Dynamic electrophoretic mobility and zeta potential were evaluated.
- The effect of varying pH and salt concentration on latex dispersions was studied.
Main Results:
- Corrected CVI values for A-latex and C-latex remained relatively constant above specific volume fractions (>0.04 and >0.03, respectively).
- A-latex showed aggregation below pH 2.5 and above 0.06 mol/L electrolyte concentration.
- C-latex dispersions became unstable at 0.3 and 1 mol/L NaCl concentrations.
Conclusions:
- Electroacoustic methods effectively characterize concentrated latex dispersions.
- Colloidal stability is dependent on pH and electrolyte concentration, aligning with DLVO theory predictions.
- Understanding these parameters is critical for optimizing pharmaceutical coating formulations.
