| 1 | Match the Bottle to the Formula | Use a container material that is compatible with water-based, alcohol-containing, oil-containing, or film-forming formulas. The inner surface should not promote leakage, swelling, cracking, or unwanted adsorption. | The formula should remain stable without visible color change, odor change, separation, or viscosity variation caused by contact with the package. | Store filled samples at room temperature and elevated temperature, then compare appearance, odor, viscosity, and mass against a control sample. | No visible incompatibility during the defined shelf-life study. |
| 2 | Control Product Flow | Select a wiper, orifice, and applicator opening that control the amount of liquid reaching the brush or felt tip. The wiper must fit securely and consistently. | The bottle should deliver a smooth, even line without flooding, skipping, excessive dripping, or difficult reloading of the applicator. | Measure fill weight before and after repeated dispensing cycles and assess line quality on a standardized test surface. | Consistent dose and line width across repeated uses. |
| 3 | Check Closure and Leak Resistance | The cap should close fully with reliable thread, snap-fit, or friction-fit engagement. The seal must protect the formula during transport and storage. | The package should resist leakage when stored upright, inverted, and horizontally, including after normal handling and vibration. | Perform inversion testing, vibration testing, cap torque checks, and pressure or vacuum testing when appropriate for the package design. | No visible leakage after the agreed transport simulation. |
| 4 | Prioritize Applicator Compatibility | Ensure the bottle neck, wiper, cap, and applicator are dimensionally matched. The applicator should be protected from contamination while remaining easy to remove. | The brush or tip should retain its shape, resist shedding, and provide controlled flexibility for both fine and broad strokes. | Inspect dimensional fit, perform repeated insertion and removal cycles, and evaluate application precision with trained users. | Secure fit with no visible shedding and comfortable application. |
| 5 | Evaluate Drying and Film Performance | The bottle and applicator system should support the intended formula without exposing it to excessive evaporation during normal use. | The applied film should dry within the intended time, provide uniform coverage, resist ordinary smudging after drying, and remain removable with the specified cleanser. | Measure drying time, rub resistance, flex resistance, and removal performance under controlled temperature and humidity conditions. | Uniform film and repeatable drying time within the product specification. |
| 6 | Design for Handling and Ergonomics | Choose a stable base, comfortable grip, readable fill level, and cap shape that supports controlled opening and closing. Avoid sharp edges and unstable proportions. | The package should be easy to hold, open, close, and store without tipping during normal consumer use. | Conduct drop, tip-over, opening-force, closing-force, and user handling tests using representative samples. | Stable during use with no hazardous sharp edges or difficult closure operation. |
| 7 | Verify Quality, Compliance, and Sustainability | Define material specifications, critical dimensions, decoration limits, recycled-content requirements where applicable, and compatibility with the intended recycling stream. | Each production lot should meet agreed requirements for appearance, dimensions, closure function, cleanliness, and product protection. | Use incoming inspection, dimensional sampling, functional testing, migration or safety assessments where required, and documented batch traceability. | Documented acceptance criteria with consistent lot-to-lot results. |
