Blinding solid oral dosage forms is a critical requirement in comparative clinical studies, where even subtle visual or physical differences can introduce bias. Over-encapsulation offers a practical and economical way to conceal tablets or capsules within an outer shell, ensuring subjects and investigators cannot distinguish between active treatment and placebo.
When blinding is poorly executed, trial participants may identify differences in appearance, weight, or feel—jeopardizing data integrity, increasing variability, and potentially leading to costly study delays. That’s why successful over-encapsulation demands both technical precision and manufacturing expertise.
With decades of hands-on experience, our specialists deliver compliant, scalable, and cost-efficient blinding strategies tailored to your study design, dosage form, and patient population.
Achieving effective over-encapsulation requires careful control of multiple design and processing elements to preserve dosage performance while maintaining complete blinding:
Active drug and placebo capsules are manufactured to be visually identical, eliminating cues related to color, size, or finish.
Capsules are selected and designed specifically for over-encapsulation, incorporating opaque materials, secure double-locking mechanisms, and appropriate sizing to improve swallowability and patient adherence—especially in pediatric and special-population trials.
Backfill materials are used to standardize capsule weight and internal movement, preventing differentiation by shaking, squeezing, or handling. Formulations are optimized to minimize excipient and lubricant use while maintaining consistent sensory feedback.
Depending on product characteristics and project scale, we apply manual, semi-automated, or fully automated over-encapsulation techniques to ensure efficiency without compromising quality.
Beyond traditional over-encapsulation, we support alternative and supplemental blinding strategies, including:
For most projects, we utilize semi-automated capsule filling systems optimized for over-encapsulation and powder filling. Bench-top equipment is also available to efficiently support small-batch requirements and early-phase studies.
Effective blinding removes visual and physical cues that could influence investigator judgment or participant perception, supporting unbiased data collection.
Tamper-resistant capsule designs discourage opening or manipulation, reducing the risk of unblinding during the study.