External Drug Delivery Device Sterilization with Pulsed NO2
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Solution Overview
Problem
Existing external sterilization methods for drug delivery devices, such as syringes, face challenges in achieving effective microbial reduction while minimizing impact on medicament integrity due to occluded spaces and absorption of sterilization gases by plastic and rubber components, which can lead to infections like endophthalmitis and discoloration.
Innovation Solution
A method using Nitrogen Dioxide (NO2) sterilization with controlled vacuum levels, dwell times, and multiple gas pulses, followed by aeration, to achieve at least 2 logs microbial reduction without adversely affecting the medicament.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional external sterilization methods are used on assembled pre-filled syringes, then sterilization coverage is improved, but occluded spaces between components prevent complete sterilization
Solution Approach 1:
The sterilization process is divided into multiple sequential gas pulses rather than a single continuous exposure. Each pulse allows the sterilant gas to penetrate different areas of the device, including occluded spaces, with intervals between pulses allowing gas redistribution and penetration into previously inaccessible areas.
Solution Approach 2:
The sterilization employs periodic cycling of the sterilant gas through the chamber, with repeated introduction and removal cycles. This periodic action allows the gas to progressively penetrate occluded spaces between syringe components over multiple cycles, achieving complete sterilization coverage that a single continuous exposure cannot achieve.
2Reliability
If sterilization gas is introduced to achieve microbial reduction, then sterility assurance is improved, but plastic and rubber components absorb the gas leading to discoloration
Solution Approach 1:
The sterilization process uses multiple gas pulses with controlled duration and concentration rather than a single prolonged high-concentration exposure. This partial action approach achieves the required sterility assurance level while limiting the total accumulated exposure dose to plastic and rubber components, thereby preventing discoloration.
Solution Approach 2:
The sterilization gas is introduced in rapid sequential pulses rather than continuous prolonged exposure. Each pulse is brief and intense enough to achieve microbial kill, then quickly removed before significant absorption by plastic and rubber components can occur, thus achieving sterilization while avoiding discoloration.
3Reliability
If higher sterilization gas concentration and longer exposure time are used, then microbial reduction is improved, but impact on medicament integrity worsens
Solution Approach 1:
The sterilization employs periodic pulsing of the sterilant gas with controlled concentration and duration parameters. Each pulse provides sufficient microbial kill activity, while the intermittent nature of the treatment with removal intervals prevents cumulative exposure that would degrade the medicament, achieving sterility while preserving medicament integrity.
Solution Approach 2:
The sterilization process carefully controls and optimizes the parameters of gas concentration, pulse duration, and number of pulses. By adjusting these parameters to achieve the minimum effective dose for sterilization rather than excessive exposure, the process achieves required microbial reduction while minimizing impact on medicament stability and integrity.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The method effectively sterilizes drug delivery devices, ensuring a high level of microbial reduction while maintaining medicament integrity and preventing discoloration, meeting regulatory standards for sterility assurance.
Implementation Method 1
A method of externally sterilizing a drug delivery device utilizing Nitrogen Dioxide (NO2)
Implementation Method 2
by applying a vacuum level of between about 10 and 600 Torr
Implementation Method 3
aerating the sterilization chamber
Data Source
AI summary
A method of externally sterilizing a drug delivery device utilizing Nitrogen Dioxide (NO2) is provided, including placing the drug delivery device in a sterilization chamber, introducing into the chamber a dose of NO2 having a concentration of between about 2 and 20 milligrams per Liter by applying a vacuum level of between about 10 and 600 Torr and holding the vacuum level for a dwell time of between about 2 and 20 minutes, repeating the step of introducing into the chamber a dose of NO2 for a number of pulses between about 1 and 24, purging the sterilization chamber of at least substantially all of the NO2, and aerating the sterilization chamber.