Multiple response optimization of processing and formulation parameters of Eudragit RL/RS-based matrix tablets for sustained delivery of diclofenac

Strategy of eudragit coated curcumin nanoparticles delivery system: Release and cell imaging studies in simulated gastrointestinal microenvironments

Curcumin has a broad-spectrum anti-tumor effect and has no toxic side effects. However, the unique diketone structure of curcumin will undergo diketo-enol tautomerism under different acid-base conditions, resulting in its instability under physiological conditions. In addition, the low biocompatibility and absorption rate of curcumin also limit the use of curcumin drugs. In this paper, curcumin was modified by substitution of acryloyl and acrylsulfonyl groups, and four kinds of nanoparticles with regular morphology were prepared using non-toxic and non-irritating acrylic resin as coating material to improve the stability and bioavailability of the compounds. Zeta potential testing shows that the composites surface carries positive charges and have good stability. In the release experiment, four complexes have the potential for slow and controlled release. Imaging of Hela cells with different channels was performed, and the imaging results showed that the complexes could enter the cells and be absorbed by them, demonstrating good imaging performance. MTT experiments have shown that the complexes have certain anti-tumor activity and low cytotoxicity. In general, the complexes synthesized in this paper have potential in the field of drug fluorescence imaging detection. At the same time, this experiment provides a new idea for the design of slow and controlled release of drugs.

Reducing Burst Release Effect of Freely Water-Soluble Drug Incorporated into Gastro-Floating Formulation Below HPMC Threshold Concentration Through Interpolymer Complex

Undesired-burst release effect is observed in a freely water-soluble drug formulated into a gastro-floating formulation with effervescent (GFFE) delivery system. In order to address this limitation, interpolymer complex (IPC) of two swellable and non-soluble polymers, poly-ammonium methacrylate and poly-vinyl acetate, was incorporated into hydroxypropyl methyl cellulose (HPMC)-based matrix GFFE. This research studied the effect and interaction of the IPC-HPMC blending on the drug release of GFFE using a freely water-soluble drug, metformin HCl, under different threshold concentration levels and curing effect. The interaction between the IPC and HPMC was characterized using vibrational spectroscopy and thermal analyses under curing and swelling conditions. Anti-solvent followed by lyophilization had better physicochemical and physicomechanic properties than spray dying technique. The interaction was observed by a specific shifting of the vibrational peaks and alteration of the thermal behavior pattern. These effects altered the drug release behavior. Thereafter, the IPC reduced burst release effects in the initial time and during testing, and the IPC improved the HPMC matrix robustness under mechanical stress testing below threshold concentration of HPMC matrix formulated in the GFFE.

Formulation and pharmacokinetics of multi-layered matrix tablets: Biphasic delivery of diclofenac

The rapid availability of the drug at the site of action followed by maintaining its effect for a long period of time is of great clinical importance. Thus, the purpose of the present study was to prepare and evaluate multi-layered matrix tablets of diclofenac using Eudragit RL/RS blend to achieve both immediate and sustained therapeutic effects. Diclofenac potassium (25 mg) was incorporated in an outer immediate release layer to provide immediate pain relief whereas diclofenac sodium (75 mg) was incorporated in the inner core to provide extended drug release. Wet granulation was employed to prepare the inner core of the tablets that were further layered with an immediate release drug layer in the perforated pan coater. The in-vitro and in-vivo performance of the developed formulation was compared with the marketed products Voltaren® SR 75 mg and Cataflam® 25 mg. The in-vitro drug release of the prepared formulation showed similarity (f₂ = 66.19) to the marketed product. The pharmacokinetic study showed no significant difference (p > 0.05) in AUC_0-24 and C_max between the test and reference formulations. The AUC_0-24 values were 105.36 ± 83.3 and 92.87 ± 55.53 μg h/ml whereas the C_max values were 11.25 ± 6.87 and 12.97 ± 8.45 μg/ml, for the test and reference, respectively. The multi-layered tablets were proved to be bioequivalent with the commercially available tablets and were in agreement with the observed in-vitro drug release results. Stable physical characteristics and drug release profiles were observed in both long term and accelerated conditions stability studies.