Investigation of Potential Ionic Interactions Between Anionic and Cationic Polymethacrylates of Multiple Coatings of Novel Colonic Delivery System

• Published in: Drug development and industrial pharmacy 2002, Vol.28 (2), p.207-215
• Main Authors: Gupta, Vishal K., Beckert, Thomas E., Deusch, Norbert J., Hariharan, Madhusudan, Price, James C.
• Format: Article
• Language: English
• Subjects: Anions - chemistry; Biological and medical sciences; Cations - chemistry; Chemistry, Pharmaceutical - methods; Colon; Colonic delivery; Drug Delivery Systems; DSC; Eudragits; FT-IR; General pharmacology; Ionic interactions; Medical sciences; NMR; Pellets; Pharmaceutical technology. Pharmaceutical industry; Pharmacology. Drug treatments; Polymers - chemistry; Polymethyl Methacrylate - chemistry; Spectroscopy, Fourier Transform Infrared; Temperature
• ISSN: 0363-9045; 1520-5762
• DOI: 10.1081/DDC-120002454

ABSTRACT The objective of this work was to investigate potential interactions between anionic (Eudragit FS) and cationic (Eudragit RL) polymethacrylates of multiple coatings of a novel colonic drug delivery system. Aqueous films of pure polymers Eudragit FS (FS) and Eudragit RL (RL) and their superimposed film (FS-RL) were cast on glass slabs. The potential ionic interactions were studied by analyzing the dried films using differential scanning calorimetry (DSC), Fourier transform-infrared spectroscopy (FT-IR), and nuclear magnetic resonance (NMR). The glass transition temperatures (Tg) of pure RL and FS were 60°C and 22°C, respectively; FS-RL showed two distinct glass transitions at 59°C and 24°C in the second heating cycle. In the 13C-MAS spectra of the samples in the solid state, no shifts of the resonance could be detected in the superimposed film compared with the pure polymers. The FT-IR spectra of the superimposed film did not show any significant shift of the bands of the $ \ndash {\rm NMe}_{\rm 3}^{\rm + } $ group of RL and the -COO− function of FS compared with the spectra of the pure polymers. No ionic interactions between anionic and cationic polymethacrylates were revealed by DSC, FT-IR, and NMR.