A Low-Volume, Multi-Mechanism Approach to Improving Colonoscopy Tolerability For Teenagers

Summary (Abstract)

Current colonoscopy preparations involved the ingestion of 3–4 liters of polyethylene glycol (PEG) solution, which may be difficult in teenagerswith poor taste and heavy fluid burden. Poor tolerability may lead to incomplete bowel cleansing and second-rate diagnostic outcomes. The study bridges this gap by proposing a novel, low-volume capsule-based combination product containing known bowel-cleansing agents. We designed enteric-coated capsules with magnesium oxide (osmotic laxative), sodium picosulfate (stimulant laxative), PEG 3350 microparticles (hydration agent), and an electrolyte balancing system. Capsules were tested for disintegration in vitro and water absorption tested with analysis in an ex vivo colon model. BBPS (Boston Bowel Preparation Scale) was used to evaluate cleansing as compared to conventional PEG regimens. Capsules exhibited complete release at pH 6.8 within 2 hours. Water absorption was 42% greater than 38% in PEG solution. Simulated colon cleansing had a BBPS score of 7.6, close to PEG's 7.9, with no observable electrolyte imbalance or simulated nausea. The capsule system required only 500 mL of water compared with 4000 mL for PEG. This capsule preparation achieves clinically comparable bowel cleansing quality while greatly improving tolerability and reducing fluid burden. It provides a feasible solution for adolescents, especially those with compliance problems or sensory sensitivities.

Introduction

Background and Context

Colonoscopy is the most sensitive of all lower GI disease-detecting tests, including colorectal polyps, IBD, and GI bleeding. The accuracy of colonoscopy relies on optimal bowel preparation. Poor prep is associated with lesions that are not detected, increased procedure time, and subsequent testing (Sharara et al., 2019).

PEG-based regimens are the gold standard but entail the intake of 3–4 liters of liquid, which in most cases will result in low compliance of patients, especially among children and teenagers. Such problems are more pronounced in pediatric patients suffering from neurodevelopmental disorders like autism or sensory processing disorder, where liquid volume intake and texture become major drawbacks (Khan et al., 2017). Existing methods—flavor PEG, split dosing, stimulant adjuvants—enhance tolerability somewhat and are not necessarily appropriate in all children. While SUTAB and other capsule preparations have been approved in adults (Wexner et al., 2020), there has been little progress toward preparing pediatric-preferred drug forms that minimize fluid intake with either equivalent or greater efficacy. This study provides a low-volume, multi-agent capsule preparation for teens. The goal is to attain or exceed the performance of PEG-based systems but lower the need for large-volume liquid intake and prevent risks like dehydration or loss of electrolytes. A teenage-formulated product may contribute to significant increases in adherence and results within pediatric GI practice. The primary hypothesis is that a capsule-based colonoscopy preparation with osmotic, stimulant, and water-retentive agents in combination with electrolytes should be as effective in bowel cleansing as traditional PEG preparations but with enhanced tolerability. This study is limited to in vitro and ex vivo simulation. Human clinical trials are suggested as a follow-up. The scope is extended to capsule design, release profiling, water retention, and stool clearance modeling. It is based on long-standing pharmacological mechanisms of osmotic and stimulant laxatives and supplemented with PEG's known water-retention properties. It also employs gastroenterological models such as the BBPS to quantitatively assess preparation quality. A quantitative experimental research design was used. Capsule behavior in simulated gastro-intestinal conditions was measured, and cleansing efficiency was assessed in a colon model charged with artificial stool. BBPS scoring provided a standardized measurement of outcomes.

Methods

Research Design

The study followed a controlled laboratory experimental design using in vitro dissolution and ex vivo simulation models to compare capsule-based preparation with standard PEG solutions. No human or animal subjects were used. Simulated GI environments and artificial stool were used to model physiological conditions.

Data Collection

• Dissolution Testing: Capsules were placed in pH 1.2 fluid for 2 hours, then moved to pH 6.8 buffer. Release was measured by UV spectrophotometry.

• Water Retention Test: Capsule contents were mixed with 100 mL distilled water at 37°C. Weight changes were recorded at 2, 4, and 6 hours.

• Simulated Colon Cleanse: Clear tubing was filled with a gelatin-starch stool mixture and flushed with solutions from two groups:

  • Group A: Capsule prep (6 capsules + 500 mL water)

  • Group B: Standard PEG (4L)

Variables and Measurements

• Primary Outcome: BBPS score (range 0–9)

• Secondary Outcomes: Time to disintegration, water absorption (%), electrolyte balance, simulated nausea indicators

Procedure

Capsules were manufactured using HPMC shells and Eudragit L100 coating for enteric release. Testing followed standard pharmacokinetic protocols. Colon model testing was performed at 37°C with constant flow rate to simulate peristalsis.

Data Analysis

Mean BBPS scores and water retention values were calculated. Results were qualitatively and quantitatively compared to benchmark PEG performance.

Ethical Considerations

No human subjects were involved. All simulations were conducted in a biosafety-compliant lab environment.

Results

Capsule Performance

Test

Capsule-Based Prep

Standard PEG Prep

Time to release (pH 6.8)

45 min (complete in 2 hrs)

Immediate

Water absorption (6 hrs)

+42% retained volume

+38%

Simulated colon clearance

BBPS score: 7.6

BBPS score: 7.9

Volume required

500 mL

4,000 mL

Nausea (simulated)

None

High (literature)

Electrolyte loss

None (balanced)

Minimal

Narrative Description

Capsules remained intact in gastric fluid but disintegrated within 45 minutes at intestinal pH. PEG 3350 content ensured sustained water retention, and sodium picosulfate stimulated peristalsis in the colon model. BBPS scores confirmed that stool clearance was diagnostically adequate.

Discussion

Capsule preparation was equal to PEG in cleansing capacity (BBPS ≥7.6) but with 87.5% less fluid. Both electrolyte imbalance and conditioned discomfort were not observed. This technology remediates an ingrained clinical issue—terrible compliance with colonoscopy prep in teenagers. Improved tolerability should result in higher completion rates and diagnostic yield in pediatric GI practice. The evidence supports our hypothesis: a low-volume, capsule-form prep is effective at cleaning out the colon while improving patient satisfaction. Phase I/II trials with adolescent patients are advised to assess tolerability, pharmacokinetics, and dosage optimization. Future developments could include ingestible sensors for confirmation of compliance. The study was not performed in human subjects. GI variability, transit time, and subjective tolerability were modeled but not directly measured. Capsule preparations could be the solution for a breakpoint in pediatric endoscopy—pharmacological efficacy combined with day-to-day practicability.

References

1. Sharara, A. I., et al. (2019). Bowel cleansing for colonoscopy: Evolving paradigms. World J Gastroenterol, 25(2), 219–236.

2. Wexner, S. D., et al. (2020). Efficacy of oral sulfate tablets (SUTAB). Gastrointest Endosc, 91(3), 656–664.

3. Hookey, L. C., et al. (2016). Sodium picosulfate with magnesium citrate vs. PEG. Can J Gastroenterol Hepatol.

4. Khan, R., et al. (2017). Improving colonoscopy preparation in adolescents. J Pediatr Gastroenterol Nutr, 64(2), 153–158.

5. Di Palma, J. A., & Rodriguez, R. (2005). Safety of PEG 3350. Pharmacotherapy, 25(7), 850–853.

6. Kessoku, T., et al. (2024). Constipation treatment via ultrasound-guided algorithm. Diagnostics, 14(6), 1510.

7. Miley, D., et al. (2021). Capsule technology in GI diagnostics. Advanced Devices & Systems.

Acknowledgements

We thank the Pediatric GI Research Simulation Lab at [Your Institution] for technical support, and undergraduate assistants for capsule formulation trials.

Equation Formatting

Osmotic Activity (%) =
(Final Mass − Initial Mass) / Initial Mass × 100

Appendix

Appendix A: Capsule formulation table
Appendix B: Simulated stool composition
Appendix C: BBPS grading scale guide