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Gastroretentive raft-forming formulations were developed in liquid and chewable tablet dosage forms to achieve prolonged delivery of quercetin in the stomach. The formulations contained a solid dispersion of quercetin and polyvinylpyrrolidone (PVP K 30) at a 1:10 w/w ratio to improve the solubility of the flavonoid. The formulations also contained sodium alginate as a gel forming agent, calcium carbonate as a calcium source and carbon dioxide producer and hydroxypropyl methylcellulose K100M as a drug release retarding polymer. The chewable tablets incorporated mannitol as a diluent. Both liquid and chewable tablet formulations exhibited rapid floating behaviour (lag time < 1 min) and long floating duration (>24 h) in 0.1 N HCl. The optimized liquid formulation showed superior characteristics based on high raft strength (10.4 g) and sustained release of quercetin (93 % over 8 h) whereas the optimized chewable tablet formulation exhibited lower raft strength (7.2 g) and lower drug release (79 % in 8 h). The optimized liquid and chewable tablet formulations were found to induce anti-inflammatory activity in cell culture using RAW 264.7 cells macrophages and enhance the migration of human gastric adenocarcinoma (AGS) epithelial cells in vitro , indicating wound healing potential for treatment of gastric ulcers.

Regarding polymer‐drug conjugation, the reaction and drug characteristics are of important because they reflect the possibility of conjugation. Tri‐ and dicomponent azido‐functionalized copolymers were initially synthesized. Tricomponent copolymers consisted of caproyl, azido‐substituted caproyl, and ethylene glycol repeating units, whereas dicomponent ones contained solely the last two repeating units. In parallel, the terminal alkyne derivatives of methotrexate (MTX) and folic acid (FOL) were synthesized by coupling reaction using N,N‐dicyclohexylcarbodiimide and 4‐dimethylaminopyridine with an additional N‐hydroxysuccinimide for FOL coupling. By click reaction, MTX and FOL were successfully conjugated with tri‐ and dicomponent copolymers, respectively, without polymer chain degradation. The grafting efficiencies of MTX and FOL were higher than 77 and 68% by using CuI/1,8‐diazabicyclo[5.4.0]undec‐7‐ene and CuSO4.5H2O/sodium ascorbate, respectively. According to the differential scanning calorimetry thermograms, MTX did not change the semicrystalline property of copolymers except for high % molar grafting, whereas the presence of FOL affected thermal properties of copolymer except at 5 molar grafting. The resultant copolymers could be further used as polymer‐drug conjugate delivery system for cancer therapy. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013

Curcumin, a polyphenolic extract from the rhizomes of turmeric, exhibits antioxidant, anti-inflammatory, and anticancer activities, which are beneficial for the treatment of gastric diseases. However, curcumin’s therapeutic usefulness is restricted by its low aqueous solubility and short gastric residence time. In this study, curcumin-loaded solid dispersion (ratio 1:5) was prepared using Eudragit® EPO (Cur EPO-SD), resulting in an approximately 12,000-fold increase in solubility to 6.38 mg/mL. Expandable films incorporating Cur EPO-SD were subsequently prepared by solvent casting using different types of starch (banana, corn, pregelatinized, and mung bean starch) in combination with chitosan. Films produced from banana, corn, pregelatinized and mung bean starch unfolded and expanded upon exposure to simulated gastric medium, resulting in sustained release of 80% of the curcumin content within 8 h, whereas films based on pregelatinized starch showed immediate release characteristics. Curcumin-loaded expandable films based on different types of starch exhibited similar cytotoxic effects toward AGS cells and more activity than unformulated curcumin. Furthermore, the films resulted in increased anti-inflammatory activity against RAW 264.7 macrophage cells compared with the NSAID, indomethacin. These findings demonstrate the potential of expandable curcumin-loaded films as gastroretentive dosage forms for the treatment of gastric diseases and to improve oral bioavailability.