3D Printing of PVA Capsular Devices for Applications in Compounding Pharmacy: Stability Evaluation and In Vivo Performance

Abstract

Background: The personalization of medication through 3D printing enables the development of capsular devices (CDs) tailored to patient-specific needs. This study aimed to evaluate the stability and in vivo performance of 3D-printed polyvinyl alcohol (PVA) CDs with 0.4 and 0.9 mm width wall thicknesses (WT) compared to traditional hard gelatin capsules (HGCs). Methods: Capsules were tested for swelling, erosion, adhesion, water sorption, and in vitro disintegration. Additionally, the release of the model drug (losartan potassium) from CDs was evaluated. In vivo capsule opening times were assessed in dogs using X-ray imaging. Stability studies were conducted under natural (25 ± 2 °C, 60 ± 5% RH) and accelerated (40 ± 2 °C, 75 ± 5% RH) storage conditions. Results: CDs with 0.4 mm WT (CD-0-0.4) exhibited higher swelling and erosion, lower adhesion, and faster disintegration, leading to a more immediate drug release, comparable to HGCs. A strong correlation was found between in vitro and in vivo disintegration behavior. Water sorption tests revealed lower moisture affinity for PVA CDs compared to HGC. Stability studies showed that CD-0-0.4 retained its physical and chemical properties. Instead, CDs with 0.9 mm WT (CD-0-0.9) were sensitive to storage, particularly under accelerated aging, which affected their integrity and release profile. Conclusions: These findings highlight the potential of PVA-CDs, especially the 0.4 mm design, as a promising and stable alternative for compounding pharmacy applications, offering an effective platform for personalized oral drug delivery.

Keywords: 3D printing; capsular devices; fused deposition modeling; in vivo studies; magistral compounding; stability studies.

Figure 1

CAD designs of CDs: (a) isometric view, (b), (c) internal views of CDs 0–0.4 and 0–0.9, respectively.

Figure 2

Schematic representation of the experimental setup used for the adhesion test.

Figure 3

Profiles of (a) swelling and (b) erosion at different immersion times for CD–0–0.4 and CD–0–0.9.

Figure 4

Adhesion test F_max values for (a) CD–0–0.9 and (b) CD–0–0.4. Letters correspond one-way analysis of variance.

Figure 5

Water sorption as a function of RH for HCG, CDs, and PVA filament.

Figure 6

FTIR spectra for LP. (a) CD–0–0.4 and (b) CD–0–0.9 at t₀, and one and three months under natural conditions.

Figure 7

DSC thermograms for LP. (a) CD–0–0.4 and (b) CD–0–0.9 at t₀, and one and three months under natural conditions.

Figure 8

(a) Weight, (b) length, (c) height for CD–0–0.4 in different storage conditions, and (d) weight, (e) length, and (f) height for CD–0–0.9 in different storage conditions. Letters correspond one-way analysis of variance.

Figure 9

Dissolution test for (a) CD–0–0.4 and (b) CD–0–0.9 at t₀ and different storage conditions.

Figure 10

HGC size 0 and CDs used for the in vitro and in vivo studies.

Figure 11

Opening of (a) HGC size 0, (b) CD–0–0.4, and (c) CD–0–0.9 in the in vitro study. The red circles highlight the location of the contrast agent.

Figure 12

X-ray images of dog’s abdomen showing the HGCs filled with BaSO₄ at different time points.

Figure 13

X-ray images of dog’s abdomen showing the CD–0–0.4 filled with BaSO₄ at different time points.

Figure 14

X-ray images of dog’s abdomen showing the CD–0–0.9 filled with BaSO₄ at different time points.