Crimp caps for pharma applications : How to ensure quality assurance

If you are in the pharmaceutical industry, you already know that quality assurance should be one of your top priorities. Ensuring properly sealed vials with an adequate crimping process and the best-in-the-market seal caps is essentially a necessary step to achieve the highest objective in pharma production: guaranteed patient safety.

If you are concerned about quality assurance when it comes to crimping vials, you have come to the right place. In this article, we cover everything you need to know about quality control, safety, and assurances when crimping vials for pharmaceutical applications.

The importance of quality assurance for vaccine vials

Most commonly, injectable solutions will be configured in a glass vial with a tightly sealed rubber stopper, also referred to as vial stopper, closed off with an aluminum seal cap, such as flip-off cap. Although there is quality control that should go into the glass vial as well, this article will focus on what seals the product. A perfect seal does not only protect against any type of contamination and environmental factors, but it is an essential contribution to medication safety as it guarantees the integrity of the product.

It is essential to not overlook the process of crimping vials as the elegance and effectiveness of a perfect seal are required to fulfill quality assurance on seal superiority and container closure integrity. A sufficiently designed process of crimping vials will ensure vial – which essentially results in injection solution – quality and integrity while minimizing product rejections during the manufacturing process.

Getting the right crimping equipment

When it comes to crimping vials for pharmaceutical applications, ensuring top-notch quality assurance is paramount, especially in the context of high-speed filling lines. Selecting the right crimping equipment becomes a critical factor in achieving smooth and efficient production while maintaining the integrity of the products.

With numerous crimp equipments available in the market, it's essential to find the most suitable one that seamlessly fits the task of crimping aluminum caps onto vials and glass bottles at high speeds. In such fast-paced scenarios, you want to be sure on the equipment’s ability to deliver rapid, precise, and consistent results. An ideal crimping tool for high-speed filling lines should offer adjustable and reproductible rotation speed, table height and crimping-pressure settings, allowing for fine-tuning of each individual stopper/cap combination and ensuring stringent quality standards throughout the manufacturing process.

You also want to look for hardened crimp jaws since they will allow for longer endurance, hence reducing the cost of replacing legacy equipment. It is worth considering that there are certain crimping tools offered for flip-off caps, as these are considered the best seal caps in the market for quality assurances, which we will later discuss.

Quality control on crimping vials

As the crimping process is a critical aspect of ensuring patient safety, it requires careful assessment and examination. Quality assessment on crimping vials can be divided into two subcategories: the crimping technique and the crimp cap itself.

Faulty tightness: over-crimping and under-crimping

Depending on the properties of the cap beading and the thickness of stopper flange, the pressure and height might need to be adjusted when crimping vials. This needs to be considered even when using the same vial and cap, as the pressure and height should always be controlled for quality assurance and adjusted if needed.

Without proper adjustment to the vial crimper, glass vials are subject to over-crimping and under-crimping. Over-crimping is a serious problem to not overlook when crimping vials as it can cause coring and inadequate stopper resealing. You can recognize over-crimping as the surface of  injection stopper will be convex. On the other hand, under-crimping can also cause problems as it can lead to evaporation issues. You can recognize under-crimping as the aluminum of the beading will not fit tightly around the crimped neck. In general, when a vial is crimped correctly, the crimp cap should not rotate and the stopper should be smooth and level with no signs of major buckling or creases. With a perfect crimp, the sides of the cap should also be flat, with no sign of damage from the tool or any other external factors.

In addition to meticulous crimping techniques and defect detection, Closure Integrity Tests (CCIT) serve as an indispensable part of quality control to avoid faulty tightness. These tests involve non-destructive testing methods to assess the hermetic sealing of vials and verify that they are free from leaks. CCIT ensures the integrity of the crimped vials, safeguarding the pharmaceutical products from potential contamination and maintaining their efficacy throughout their shelf life.

Incorrect screw cap technique

If using a screw cap, the crimping is subject to an incorrect screw cap technique. If the cap is incorrectly tightened, it can jeopardize the quality and closure integrity of the glass vials. Over-tightening during the crimping process can lead to septum distortion, which happens when a cap is placed under too much pressure, causing the septum to be twisted inside the cap which leads to re-sealing issues. Over-tightening of aluminum seals can also lead to unscrewing as the cap can potentially unscrew itself from too much pressure, which leads to sampling evaporation.

Because of the subjectivity of incorrect screw cap technique and the stringent requirements, crimp caps are generally preferred over screw caps.

By combining mirroring techniques, defect detection, and CCIT in the quality control process, pharmaceutical manufacturers can confidently uphold the highest quality standards, ensuring the reliability and safety of crimping vials used in pharmaceutical applications. These rigorous assessments play a pivotal role in preserving patient safety and maintaining the trust of both healthcare professionals and consumers in the pharmaceutical industry.

A quality crimp cap for quality assurance

A quality aluminum seal for injection vials guarantees a perfect seal of the glass vial every time. The crimp cap, also known as flip-off cap or push-off cap combines an aluminum cap with a polypropylene lid. The flip cap ensures quality assurance on three main points, presented below:

1. Obvious tamper evidence

Once you have pushed off the lid from the vial, it is impossible to put it back into place. This ensures tamper evidence as it becomes evident if the product has been manipulated or its integrity has been violated. As a result, you know that if the product is intact, the integrity of the product is ensured.

2. Safety features

The flip-off cap has all the required safety features to ensure the perfect quality seal, including enhanced protection of the injection site which includes safety against microbiological or particulate contamination. The customized and recognizable product design also ensures safety against product mix-ups and counterfeiting. The lids are provided in different shapes, colors, dimensions, and with the option to be printed on.

3. Ease of use

The technique of the seal cap itself increases ease of use as the consumers can easily open the product properly without having to use force, ensuring that the product will not be ruined in the process when trying to open the seal.

Quality control when crimping vials

Although you have chosen the highest quality crimping too, vial stopper, and seal cap in the market, you still want to perform quality control to ensure medication safety. There are two main quality controls you should do when ensuring quality assurance of your crimping vials. One part aims at the crimping technique, and the other part aims at the appearance of the seal. To summarize it for you, we created a quality control checklist not to overlook when ensuring quality assurance.

Defects to inspect for crimping vials:

• Missing caps or lids
• Accurate color on caps and lids
• A loose crimped seal
• Other defective crimping, such as over-crimping and under-crimping
• Damage to caps
• Any type of tampering, causing damage or manipulation to the product