Development of a gastroretentive pulsatile drug delivery platform

Design and fabrication of 3D-printed gastric floating tablets of captopril: effect of geometry and thermal crosslinking of polymer on floating behavior and drug release

The present study aims to investigate the potential of the 3D printing technique to design gastroretentive floating tablets (GFTs) for modifying the drug release profile of an immediate-release tablet. A 3D-printed floating shell enclosing a captopril tablet was designed having varying number of drug-release windows. The impact of geometrical changes in the design of delivery system and thermal cross-linking of polymers were evaluated to observe the influence on floating ability and drug release. Water uptake, water insolubilization, Differential Scanning Calorimetry (DSC), and Attenuated Total Reflection-Fourier Transform Infrared Spectroscopy (ATR-FTIR) were performed to assess the degree of thermal cross-linking of polyvinyl alcohol (PVA) filament. The 3D-printed GFT9 was considered the optimized gastric floating tablet that exhibited >12 h of total floating time with zero floating lag time and successfully accomplished modified-drug release by exhibiting >80% of drug release in 8 h. The zero-order release model, with an r2 value of 0.9923, best fitted the drug release kinetic data of the GFT9, which followed a super case II drug transport mechanism with an n value of 0.95. The optimized gastric floating device (GFT9) also exhibited the highest MDT values (238.55), representing slow drug release from the system due to thermal crosslinking and the presence of a single drug-releasing window in the device.

3D Printed Intragastric Floating and Sustained-Release Tablets with Air Chambers

This work aimed to use hot-melt extrusion (HME) and dual fused deposition modeling (FDM) 3D printing technology to develop a novel intragastric floating and sustained-release drug delivery system. The intragastric floating and sustained-release tablet was engineered by employing hydroxypropyl methylcellulose (Affinisol^TM HPMC HME 15LV) for a drug-loaded core and polylactic acid (PLA) for an insoluble shell with an air chamber. Filaments for the drug-loaded core were compounded using a single-screw hot melt extruder. 3DMAX software was utilized to design a core with a complementary shell which consisted of a hollow chamber at the top and a drug-release window with different sizes (radius in 1.5, 2.5, 3, 3.5, 4.5 mm) at the bottom. Pharmaceutical characterization, solid dispersion evaluation, and drug release behavior were studied. The model drug in all formulations kept stable, and part of the drug in the extruded filaments and 3D printed tablets became amorphous. The introduction of an air chamber reduced the tablet density to below 0.9 g/cm³ and the 3D printed tablets floated immediately and continuously during the drug release process. The presence of the insoluble shell greatly prolonged the drug release time, and the drug release rate was positively correlated with the area of the release window. In addition, compared with shellless tablets, the 3D printed tablets with air chambers (radius in 4.5 mm) showed closer zero-order drug release for 24 h and released drug by diffusion-erosion combined mechanism. The developed intragastric floating and sustained-release tablets with air chambers could be applied to various drugs and provided a new way for the development of personalized drug delivery systems.

Repka M. Novel Gastroretentive Floating Pulsatile Drug Delivery System Produced via Hot-Melt Extrusion and Fused Deposition Modeling 3D Printing

This study was performed to develop novel core-shell gastroretentive floating pulsatile drug delivery systems using a hot-melt extrusion-paired fused deposition modeling (FDM) 3D printing and direct compression method. Hydroxypropyl cellulose (HPC) and ethyl cellulose (EC)-based filaments were fabricated using hot-melt extrusion technology and were utilized as feedstock material for printing shells in FDM 3D printing. The directly compressed theophylline tablet was used as the core. The tablet shell to form pulsatile floating dosage forms with different geometries (shell thickness: 0.8, 1.2, 1.6, and 2.0 mm; wall thickness: 0, 0.8, and 1.6 mm; and % infill density: 50, 75, and 100) were designed, printed, and evaluated. All core-shell tablets floated without any lag time and exhibited good floating behavior throughout the dissolution study. The lag time for the pulsatile release of the drug was 30 min to 6 h. The proportion of ethyl cellulose in the filament composition had a significant (p < 0.05) effect on the lag time. The formulation (2 mm shell thickness, 1.6 mm wall thickness, 100% infill density, 0.5% EC) with the desired lag time of 6 h was selected as an optimized formulation. Thus, FDM 3D printing is a potential technique for the development of complex customized drug delivery systems for personalized pharmacotherapy.

Design of a Time-Controlled Pulsatile Release System for Propranolol Using the Dry-Coated Method: In Vitro and In Vivo Evaluation

The objective of this study was to design a time-controlled pulsatile release (TCPR) system containing propranolol (PNH) as an active pharmaceutical ingredient. Here, the developed dosage forms were coated with hydroxypropyl-methylcellulose (HPMC) and other excipients as barrier layer using dry-coated technology. The influence of HPMC, microcrystalline cellulose (MCC), and lactose in the outer coating and the coating weight on drug release were investigated. Then, a three-factor, five-level central composite design (CCD) and response surface method were used to optimize the formula of the coating. After data processing, the optimal prescription was found to be as follows: HPMC E50(X₁) 86.2 mg, MCC(X₂) 43.8 mg, and lactose (X₃) 21.3 mg in the coating. Moreover, the in vitro tests showed that the optimized formulation of TCPR had a lag time of 4 h followed by a 4-h drug release. Also, determination of the extent of erosion of the TCPR tablets revealed that the lag time is related to the coating erosion speed. The in vivo test in beagle dogs and comparison of the parameters for the TCPR tablets and reference preparations showed significant differences for T_max (7.83 ± 0.408 and 2 ± 0.00) and C_max (185.45 ± 28.561 and 587 ± 45.27 ng/ml) but no significant differences in the AUC_0-∞ (1757.876 ± 208.832 and 1779.69 ± 229.02 ng h/ml). These results demonstrated that the TCPR tablets successfully prolonged the lag time and controlled the release of propranolol.