Development of Novel pH-Sensitive Eudragit Coated Beads Containing Curcumin-Mesalamine Combination for Colon-Specific Drug Delivery

This research aims to develop a drug delivery system that effectively treats colitis while administering curcumin/mesalamine by coating alginate/chitosan beads with Eudragit® S-100 to target the colon. Beads were tested to determine their physicochemical characteristics. Coating with Eudragit® S-100 prevents drug release at a pH of less than 7; this was demonstrated by in-vitro release conducted in a medium with gradually varying pH to mimic circumstances in various regions of the gastrointestinal tract. This study examined the efficacy of the coated beads in treating acetic acid-induced colitis in rats. Results showed that spherical beads were formed with an average diameter of 1.6–2.8 mm, and the obtained swelling ranged from 409.80% to 890.19%. The calculated entrapment efficiency ranged from 87.49% to 97.89%. The optimized formula F13 (which was composed of mesalamine-curcumin active ingredients, Sodium alginate as a gelling agent, chitosan as a controlled release agent, CaCl2 as a crosslinking agent, and Eudragit S-100 as a pH-sensitive coating agent) demonstrated the best entrapment efficiency (97.89% ± 1.66), swelling (890.19% ± 60.1), and bead size (2.7 ± 0.62 mm). In formulation #13, which was coated with Eudragit S 100, curcumin (6.01 ± 0.04%) and mesalamine (8.64 ± 0.7%), were released after 2 h at pH 1.2; 6.36 ± 0.11% and 10.45 ± 1.52% of curcumin and mesalamine, respectively, were then released after 4 h and at pH 6.8. Meanwhile, at pH 7.4, after 24 h, approximately 85.34 ± 2.3% (curcumin) and 91.5 ± 1.2% (mesalamine) were released. Formula #13 significantly reduced the colitis, and this suggests that the developed hydrogel beads can be used for delivering curcumin-mesalamine combinations to treat ulcerative colitis after adequate research.

4.1. Chemicals and Reagents

All chemicals were purchased in the analytical grades. Mesalamine, curcumin, SALG, chitosan, hydroxypropyl-β-cyclodextrin (HP-β-CD), and Eudragit^® S-100 were obtained from Sigma-Aldrich (St. Louis, MO, USA). Tri-ethyl citrate (TEC), liquid paraffin, span-80, acetic acid (99%), and sodium hydroxide were purchased from Sigma-Aldrich. Acetone, n-hexane, HCl, Mg-stearate, potassium dihydrogen phosphate, di-sodium-hydrogen-phosphate, methanol, and ethyl alcohol (99%) were procured from El-Nasr Pharmaceutical Co. for Chemicals (Cairo, Egypt). Anhydrous calcium chloride (Fine GRG 90%) was supplied by Fisher Scientific (Fairlawn, NJ, USA).

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Heikal, E.J.; Kaoud, R.M.; Gad, S.; Mokhtar, H.I.; Alattar, A.; Alshaman, R.; Zaitone, S.A.; Moustafa, Y.M.; Hammady, T.M. Development of Novel pH-Sensitive Eudragit Coated Beads Containing Curcumin-Mesalamine Combination for Colon-Specific Drug Delivery. Gels 2023, 9, 264.
https://doi.org/10.3390/gels9040264