The manufacture of medical devices is subject to stringent and comprehensive regulations. The type of the medical device determines the cleanliness requirement of the environment. For most device classes, contamination control is achieved through the use of a clean room facility. A clean room is a controlled environment where products are manufactured, in which the concentration of airborne particles is controlled to specified limits. These contaminants are generated by people, process, facilities and equipment and must be continually removed from the air. The level to which these particles need to be removed depends upon the standards required. Strict rules and procedures are followed to prevent contamination of the product. The only way to control contamination is to control the total environment- air flow rates and direction, pressurization, temperature, humidity, specialized filtration and the sources of these particles all need to be tightly controlled.
As per an article by Joseph Fox and Kevin McCann, clean rooms provide control of airborne particles to levels that are appropriate for contamination-sensitive manufacturing activities. A clean environment is one where the concentration of contaminating particles, particularly airborne particles, is controlled to predefined limits while a sterile environment is one that is free from microorganisms and their spores. An environment may be clean without being sterile and vice versa. Clean rooms are classified to a number of standards, the most common being ISO 14644, which is based on the maximum allowable concentration of particles greater than 0.1 µm/cubic meter of air. Compliance to a specific class can be made at particle sizes between 0.1 and 5.0 µm depending on clean room class, design and process requirements.
For validation of medical molding (as noted by the Global Harmonization Task Force, SG 3 Guide), machine operations in controlled environments are scrutinized. Emissions from the molding process that could affect product quality must consistently be kept within specified limits. Most medical molding is performed in a Class 8 environment (less than 3,520,000 particles at 0.5 µm and greater per cubic meter of air). There is an increasing trend toward Class 7, Class 6 and cleaner environments.
Particulate cleanliness classification is normally determined using a discrete particle counter (DPC). A clean room is considered compliant if the average concentration at each location, and the 95% upper confidence limit (required if there are fewer than 10 locations), do not exceed the particle concentration limits of the specified ISO class at the considered particle size.
Clean room airflow can be characterized as unidirectional (laminar), non unidirectional (turbulent) or mixed (combination of unidirectional and non unidirectional zones) flow. Clean rooms classified at ISO Classes 6, 7 and 8, which include most medical moldings, require clean rooms which are typically non unidirectional airflow designs with average room air change rates that can range from less than 30 to more than 250 changes/hour. The turbulent nature of the airflow in such clean rooms makes the air change rate virtually nonexistent in some locations even though there are many air changes. Unidirectional flow clean rooms commonly used for pharmaceutical and microelectronic production are typically designed with air change rates often in excess of 700/hour. They provide uniform air velocity throughout the entire room.
The concentration of the particle contribution from injection molding equipment will vary with the different volumes of air into which it is released (diluted). A decrease in volume will cause an increase in concentration.
Electric machine has particle generation characteristics that were within the particle concentration limits of ISO Classes 8 through 5. Electric machine and hybrid machine show similar particle generation characteristics that are well within the concentration limits for ISO Classes 6, 7 and 8 with some compatibility at Class 5. Hybrid machines exhibit particle generation characteristics that are within the concentration limits for ISO Classes 7 and 8. Both machines generate high particle concentrations in and around the injector nozzles and within the clamp/mold enclosures. Experiments show that electric machines are inherently more suitable for medical clean room applications and in many cases hydraulic machines are equally, if not more compatible, and are able to demonstrate compliance to the most stringent ISO standards.
Growing per capita income and adoption of new lifestyles has made healthcare services in India to undergo rapid change to meet the increasing demand for quality healthcare services. Urban areas have seen the construction of new, state-of-the-art hospitals and associated satellite facilities, while others in semi-urban and rural areas are yet to avail the same healthcare infrastructure. This has fueled the demand for healthcare equipment and devices across segments and according to Cygnus Research estimates Indian medical equipment and devices market in 2008 was US$2.75 bln in 2008. The medical instruments & appliances segment, which has been estimated at US$690 mln in 2008, is further projected to reach US$1236.5 mln in 2012. The medical devices and equipments market is poised for phenomenal growth due to focused investment in healthcare infrastructure and foreign manufacturers of medical devices and equipments eyeing for India for creating global hub for manufacturing medical devices and equipments. According to Cygnus Research estimates the market is expected to reach US$5 bln by 2012 with an annual growth rate of nearly 15%.
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