# Optimizing Intestinal Drug Delivery: A Comparative Study of Commercial Enteric Capsules and 3D-Printed Capsules with Customizable Release Profiles for Enhanced Precision Medicine

## TL;DR

3D-printed capsules can control drug release in the intestines, offering a customizable alternative to traditional enteric capsules for precision medicine.

## Contribution

3D-printed capsules with tunable release profiles were developed and compared to commercial enteric capsules for precision drug delivery.

## Key findings

- 3D-printed capsules showed zero drug release in gastric pH for 2 hours.
- Acetaminophen was released in a controlled, sustained manner in intestinal conditions for up to 5 hours.
- The polymer ratio directly influenced the release rate and duration, with higher HPMC-AS content extending release.

## Abstract

What are the main findings?
3D-printed capsules provided zero drug release in gastric pH for 2 h.Controlled, sustained acetaminophen release achieved in the intestinal phase up to 5 h.Polymer ratio (HPMC-AS:PEG) directly tuned the release rate and duration.Printed capsules met the pharmacopeial weight and uniformity criteria.Korsmeyer–Peppas model indicated diffusion + erosion release mechanism.

3D-printed capsules provided zero drug release in gastric pH for 2 h.

Controlled, sustained acetaminophen release achieved in the intestinal phase up to 5 h.

Polymer ratio (HPMC-AS:PEG) directly tuned the release rate and duration.

Printed capsules met the pharmacopeial weight and uniformity criteria.

Korsmeyer–Peppas model indicated diffusion + erosion release mechanism.

What are the implications of the main findings?
Demonstrated feasibility of patient-specific, tunable oral dosage forms via 3D printing.Enabled personalized, sustained-release therapy without traditional enteric coating.Simplified capsule fabrication into a one-step process integrating protection and control.Supports the future of on-demand drug manufacturing for precision medicine.Potential to improve adherence and reduce side effects in chronic therapy.

Demonstrated feasibility of patient-specific, tunable oral dosage forms via 3D printing.

Enabled personalized, sustained-release therapy without traditional enteric coating.

Simplified capsule fabrication into a one-step process integrating protection and control.

Supports the future of on-demand drug manufacturing for precision medicine.

Potential to improve adherence and reduce side effects in chronic therapy.

Conventional gelatin capsules deliver a rapid drug release in the stomach, which is suboptimal for therapies requiring controlled and delayed release, emphasizing the need for customizable drug delivery systems for precision medicine. This study’s objective was to optimize 3D-printed capsule shells formulated with pH-responsive polymer blends—hydroxypropyl methylcellulose acetate succinate (HPMC-AS), PEG-4000, and PVA—to achieve controlled and sustained drug release, comparing profiles against a commercial enteric capsule. Capsule shells were produced via fused filament fabrication (FFF) at two ratios (80:15:5 and 70:20:10), filled with acetaminophen (250 mg), and tested using a two-stage dissolution method (simulated gastric fluid (SGF) for 2 h followed by simulated intestinal fluid (SIF) for 4–5 h). Results showed negligible drug release in SGF (≤5%) for both printed and commercial capsules. However, in SIF, the commercial capsule released its payload rapidly (>80% within 15 min), while the 3D-printed capsules achieved a prolonged, gradual release. The higher HPMC-AS content significantly extended the release duration. All capsules met the pharmacopeial weight uniformity criteria. In conclusion, the 3D-printed shells provided a controllable, sustained drug release profile, underscoring 3D printing’s potential to create tunable, patient-specific dosage forms.