Sterilization Process in Pharmaceuticals

Sterilization in overall is the process of eliminating or killing all the living organisms (microorganisms like bacteria, protozoa, microscopic fungi etc.) and their all transmissible components (reproductive and hibernating structures like spores, cysts etc.) from a specific surface or medium. It is done by applying specific methods like chemicals, radiation, heat, pressure or filtration. This is most descriptive definition which could be given for the term "sterilization" in applied microbiology. Even if specifically discussed in Pharmaceuticals the sterilization procedures are targeting the same theory. Only aim of the all methods of sterilization is to kill all microorganisms from the specified article. The sterilized material must not contain any living microbe. Any of sterilization method can be used to get sterilize the material.

Sterilization in Pharmaceuticals is related with manufacturing and utilizing practices of laboratory utensils, tools, drugs, medicine and in some occasions in ready-made culture mediums for laboratory testing. Applying chemicals with special compositions to kill microorganisms on a surface is the most familiar method of sterilization even in domestic practices. If called by group names these chemicals are known as antiseptics and disinfectants such as bactericides, bacteriostats, germicides etc.

In Pharmaceutics application of chemicals is majorly used in sterilizing surfaces but not culture mediums, medicine and drugs. The antiseptics are chemicals mainly used in killing microorganisms on human skin, but some types such as Alcohols are specially used in sterilizing surfaces of tools and lab utensils. Antiseptics stops activity of microorganisms like bacteria by obstructing their metabolic activities. Disinfectants are the major type of chemicals used in Pharmaceutical sterilization. Their composition greatly affects the multiplication of microorganisms living on surfaces (bacteriostat effect) and kills all the existing microbes (germicidal effect). Generally used disinfectants contain chemicals like Phenols, Lysols, and Chlorine compounds. Chemical sterilization is a basic process because to eliminate all microbes and to destroy their spores and cysts stronger agents like heat, radiation and pressure have to be applied. Heat sterilization has the basic theory of employing high temperature on surfaces in different methods. Some methods utilize both pressure and heat together. Heat sterilization can be mainly categorized as dry heat sterilization and moist heat sterilization. As every organism is composed in greater percentages of proteins, both methods are based on thermal destruction of proteins.

Dry heat is directly use hot air or heat of flames in order to destroy microbes and their vital structures. These methods are not applicable for equipment which is heat sensitive. Boro-Silicon glassware, petri dishes, pipettes like equipment can be sterilized using dry heat by placing them in hot air ovens not longer than 2 hours from 160- 180 C. Moist heat sterilization is done with pressure of steam especially using autoclaves. There are specific parameters of time, temperature and pressure to be used in this procedure. The standard values are 15 lb per square inch pressure, 121 C temperature for 15 minutes time period. For most heat sensitive Pharmaceutical equipment, culture mediums, drugs and medicine other methods such as radiation and filtration are used.

Radiation is majorly used for heat sensitive equipment. Energy of ionizing radiations like X-rays, UV, Gamma rays can ionize molecules which microbes are composed of. The most abundantly used type of radiation is UV. As heat or radiation could damage and change the chemical composition of drugs and medicine, filtering is used as a process of sterilization for them. All the other Thermo labile fluids are filtered using membrane filters having micro meter range pores. Most often membrane filters of 0.45 micro meter pores are used as bacteria, protozoa and most of the other microbes are larger than this size.