Method of Sterilization

Methods of Sterilization:

Definition: Sterility is the absence of viable microorganisms. It is essential that the effect of the chosen sterilization procedure on the product (including its final container or package) is investigated to ensure effectiveness and therefore the integrity of the product, which the procedure is valid before being applied in follow. guaranteeing that the selection of the instrumentality is like to permit the optimum sterilization to be applied.

Steam Sterilization:

Applicable Products: Large Volume Parenteral Liquids.

Definition: Sterilization is finished by saturated steam struggling particularly for binary compound preparation. The reference conditions for binary compound preparations ar heating at a minimum of 1210C for quarter-hour. different mixtures of your time & temperature could also be used providing it's been satisfactorily incontestible that the method chosen delivers AN adequate and duplicable level of unwholesomeness once operational habitually among the established tolerances. The procedures and precautions utilized ar like to administer a SAL (Sterility Assurance Level) of 10-6 or higher. Spores of B stearothermophilus ar suggested for validation. there's no growth of the reference microorganisms once the biological indicators are exposed to steam at 121±10C for fifteen min.

Time at Temp. Cycles for Moist Heat Sterilization are given in Table-1

Table-1

Temperature (0C)	Pressure (p.s.i.)			Minimum Holding Time (min)
	(kPa)abs	(lbf/in2)g	(bar)
115-116	172	10	1.7	30
121-123	202	15	2.0	15
126-129	242	20	2.4	10
134-138	304	32	3.0	3
106			1.6	85

      

        Ref: BP 2004, Vol.-4,  and Pharmaceutical Practice

Ethylene Oxide Gas Sterilization:

 

Applicable Products: Infusion Sets, Syringes and Scalp Vein Sets.

Definition: Ethylene Oxide is extremely effective at killing microorganisms and its activity is related to its action as an alkylating agent. Reactive hydrogen atoms on hydroxyl, carboxyl, sulphydril & amino groups can all be replaced with hydroxyethyl groups thus interfering with a wide range of metabolic activities. It is essential that penetration by gas and moisture into the material to be sterilized is ensured and followed to elimination of the gas. where attainable, the gas concentration, ratio, temperature and period of the method area unit measured and recorded.. Measurements are made where sterilization conditions are least likely achieved, as determined at validation. Spores of Bacillus subtilis var. niger are recommended for validation.

Concentration of Ethylene Oxide & Time of Exposure: Manufacturer of ethylene oxide sterilizer recommends, for most purposes, exposure to 850-900 mg/l for 3 h or 450 mg/l for 5 h, at 54⁰C. A powerful vacuum immediately is to be applied after sterilization, e.g. 1.5 kPa (15 mbar) for 2 hours. Also partial vacuums are applied to about 20 kPa (0.2 bar) and then admit sterile air to atmospheric pressure as a flushing agent. This is repeated for 5 to 6 times.

Different Factors responsible for EO Gas sterilization are given in Table-2.

Table-2

EO Gas Sterilizer	Temp.	Pressure (mbar)/ Gas Conc.	Relative Humidity	Time (HoldingTime)
Standard	540C	450 mg/L	50%	5 hours
Standard	540C	850-900mg/L	50%	3 hours
For Biological Indicator	540C	600 mg/L	60%	60 min.
At Infusion Set	450C	800/150 mbar	60%	240 min
At Syringe	310C	900/525 mbar	60%	60 min

   Ref: BP 2004, Vol.-4,  & Pharmaceutical Practice,

Dry Heat Sterilization:

Applicable Particulars: Glass Apparatus.

Definition: Sterilization by dry heat is usually carried out in a hot air oven in which heat is transferred from its source to the load by radiation, convection and to a small extent by conduction. Spores of Bacillus subtilis var. niger are recommended for validation

 Time Temperature Combinations:

·        minimum one hundred eighty degree Celsius  for not less than 30 minutes

·       minimum one hundred seventy degree Celsius for not less than 1 hour

·        minimum one hundred sixty degree Celsius for not less than 2 hours

For Depyrogenation of the Glassware, Treatment is done at 250⁰C for 30 minutes or 200⁰C for 1 hour.

Ref.: Pharmaceutical Practice and BP 2004, Vol.-4.