Introduction:
Water
for Injection is used as a medium for majority of sterile preparations.
Obviously it has to match the highest specifications as per the international
standards of pharmaceutical world.
This translates to having a WFI generation system that is built to high
sophistication level and strict process control to maintain WFI chemical
parameters within the permissible limits.
At Machinfabrik our WFI GENERATION SYTEM meets all of these demands with simplicity and style. Our team of technical experts with proven r&d capabilities have designed the MEDS to meet all quality requirements in terms of equipment construction as well as WFI QUALITY.
WE ensure careful construction to prevent any stagnation of water within
the unit in terms of dead leg areas and accurate instrumentation system
that controls the parameters of the generated WFI within permissible limits.
With this our system meets all specifications as laid down by USFDA&.
UKMCA.
Technique:
The MEDS equipment follows the distillation principle. The distillation is implemented via a double punch pyrogen separation system.
The first punch is delivered by multidirectional baffles .the steam generated from the first column is made to pass a torturous path through multidirectional baffles where pyrogen particles and droplets separate and are guided to the end of the column.
The second punch is delivered by a centrifugal type cyclone separator high up in the column. here the vapour is guided through a narrow circular channel where it begins to rotate. the vapour flow subjects the pyrogen impurities and droplets to a high centrifugal force thereby dislodging them from the vapour steam these droplets are removed by means of blow down valves at the bottom of the columns.
The distillation units are connected in series into a multiple effect system and external energy is required at the first column only, since generated steam at each column is supplied to the subsequent column.
The
generated steam vapour of the last column.& the almost condensed steam
distillate (2nd column onward)is led to the over head cooling heat exchanger,
where it is cooled by the water to generate WFI.
Features:
Double tube sheet construction for heat exchangers in first column.
Approved by USFDA
The heat exchangers have special floating design to eliminate danger of
tube cracking due to thermal stresses induced by cyclic expansion and
contraction.
The over head
cooling heat exchanger other than condensing the distillate and steam
to produce wfi serves an additional purpose of pre heating the feed water
to a temperature of almost 95 deg.c thereby facilitating the vapor generation
in the first column.
The feed water and cooling water coils are helix manufactured from a single
ss.316 or ss.316l tube and meets all the standard requirements
The feed water pump is a positive displacement piston type-reciprocating pump for feed water. These are sanitary design pumps and are free of maintenance drawbacks associated with centrifugal pumps.
Insulation of resin boded glass wool maintains the outside surface temperature of the columns to below 60 deg.c.
The entire cycle of WFI generation is completely automatic with sophisticated yet simplistic plc control. The features that the plc control does offer are:
There is precaution against storage tank overflow or storage tank empty by means of a float switch .ie. The switch communicates the water level of the tank to the plc, that causes automatic stop or start action for the WFI generation plant.
The plc is programmed to automatically dump generated wfi in case the conductivity is lesser than the predefined value assuring high quality wfi at all times
Pressure switches that communicate the pressure level on the incoming Utility lines to the plc are provided that will detect low pressure to alert the operator by means of an audiovisual alarm
A 12 point Scanner is provided for continuously recording the temperature levels at all vital points in the plant.
Trip condition of the feed pump is communicated to the plc that will generate an audiovisual alarm for operator attention.
User-friendly operator interface to allow the easy visual inspection of the cycle monitoring and control.
Sampling of WFI: the generated WFI can be provided with a collection mechanism for detailed chemical analysis.
Online printing of relevant parameters of the process is provided for process documentation.
Generated pure
steam when condensed will generate WFI meeting the below specified standards
microbiological standard
endotoxins <o.25 eu/ml
toc < 500 ppb
conductivity <1 ms at 20 deg.c
microbial limit <10 cfu per 100 ml
physio chemical standard
ammonia <0.3 ppm
calcium <0.5 ppm
carbon dioxide <4.0 ppm
heavy metals <0.5 ppm
total solids <0.001 %
chlorides <0.5 ppm
sulphates <0.5 ppm
ph =5-7
conductivity at still outlet <0.5 ms/cm at 97 oc without compensation
magnesium <1.2 ppm
nitrate <0.2 ppm
All other parameters to comply with USP and BP standard.
Applications:
Medium for sterile preparations.
Optional Features:
Pure Steam valve: if required a pure steam collection valve can be fitted between the first and the second column from where pyrogen free steam can be drawn.
