Three-Dimensional Printing of PVA Capsular Devices for Applications in Compounding Pharmacy: Effect of Design Parameters on Pharmaceutical Performance

Abstract

The creation of products with personalized or innovative features in the pharmaceutical sector by using innovative technologies such as three-dimensional (3D) printing is particularly noteworthy, especially in the realm of compounding pharmacies. In this work, 3D printed capsule devices (CDs) with different wall thicknesses (0.2, 0.3, 0.4, 0.6, and 0.9 mm) and sizes were designed and successfully fabricated varying printing parameters such as extrusion temperature, printing speed, material flow percent, and nozzle diameter. The physicochemical, pharmaceutical, and biopharmaceutical performance of these CDs was evaluated with the aim of achieving an immediate drug release profile comparable to hard gelatin capsules (HGC) for use in magistral compounding. It was observed that the disintegration time of the CDs increased with wall thickness, which correlated with a slower drug release rate. CDs with configurations presenting 0.4 mm wall thickness and sizes comparable to HGC n° 0, 1, and 2 demonstrated satisfactory weight uniformity, short disintegration times, and immediate drug release, indicating their potential as effective devices in future compounding pharmacy applications. In addition, a modified Weibull-type model was proposed that incorporates wall thickness as a new variable in predicting dissolution profiles. This model improves the process of selecting a specific wall thickness to achieve the desired dissolution rate within a specified time frame.

Keywords: 3D printing; capsular devices; drug release modeling; fused deposition modeling; magistral compounding; printing parameters.

Figure 1

Capsule Device (CD) design n° 0 (CD-0) with different wall thicknesses (CD-0-0.2, CD-0-0.3, CD-0-0.4, CD-0-0.6, and CD-0-0.9) and their corresponding internal volumes (in mm³) and dimensions (in mm).

Figure 2

CDs of different sizes with the corresponding internal volumes (in mm³) and dimensions (in mm).

Figure 3

Images of three different CD-0-0.2-printed samples ((a), (b), and (c)) showing problems in adhesion to the printing platform (I), cracks between layers (II), and bridging (III).

Figure 4

CD-0 with different wall thicknesses.

Figure 5

CD of different sizes compared with Hard Gelatin Capsules (HCG). (a) CD-0-0.4 and HGC n° 0, (b) CD-1-0.4 and HGC n° 1, and (c) CD-2-0.4 and HGC n° 2.

Figure 6

Compression work of (a) HGCs, (b) CDs of different w, and (c) CDs of different sizes (columns with the same letters indicate no significant difference among the compression work of the samples).

Figure 7

Drug release from CDs-0 of different wall thicknesses.

Figure 8

Drug release from CD-0.4 and HGCs of different sizes.

Figure 9

(a) Equation (5) model against α predicted data and (b) Equation (6) model against β predicted data.

Figure 10

Dissolution profiles of CDs of different wall thicknesses from the modified Weibull-type model and experimental points.