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October 7, 2020

Drug product continuous manufacturing often relies on multiple material feeding devices to feed the unit formula accurately and consistently into the process. An individual feeding device’s target mass flow is a function of the process total mass flow and unit formula. Maintaining the unit formula is critical to ensure product efficacy and patient safety. Therefore, the ability of the current feeding devices determines the process minimum total mass flow value. There are multiple reasons to process smaller batch sizes at low total mass flows during development and commercial manufacturing which drives the need for an individual material feeding device capable of feeding at low mass flows.


The feeding mechanism of the feeder typically involves transporting the material within its chamber and accurately metering it into the required process or a unit operation. The performance of feeding is often strongly dependent on properties of the material being fed such as bulk density, cohesiveness, flowability etc.  Therefore, it is desired for the device to accurately feed materials with
•    a bulk density of approximately 0.20 g/mL or less and (e.g. freeze-dried materials, aerosol materials) and/or
•    a flow function coefficient (FFC, measure of material flowability) of 2.0 or less. 
•    Example materials – Cab-O-Sil silicon dioxide or lubricants (magnesium stearate or sodium stearyl fumarate)


Download the Request for Information and submit your response.




Q&A Received (Updated 11/04/2020 - newest questions at top)

  1. Long/short term accuracy % goal is measured as average or RSD? Average (% of target)

  2. %RSD <3% over 60s is based on 1 or 2 sigma value? RSD would be calculated based on the standard deviation divided by the mean.

  3. Are proof and validation of accuracy part of the project scope including the required instrumentation hardware? Demonstration of accuracy and precision would be required. It is possible to use existing hardware for this like an external scale for catch samples.

  4. Can you provide more detailed information on expected operating conditions like vibration, air flow, temperature etc.? For typical pharmaceutical applications, use would be in controlled or pre-conditioned environments where temperature/humidity do not greatly fluctuate (room temperature). Vibration, air flows, and pressures may vary across applications and thus, the design should account for potential impact and consider isolation techniques where possible.

  5. On page 5 (2.3.1 Necessary features) is stated that the “Device must be cleanable / pharmaceutical grade”. Is there already clear what the specific requirements are? Is CIP mandatory or is WIP sufficient?  WIP or CIP are not required. The intent of “Device must be cleanable / pharmaceutical grade”:

    1. Materials of construction must align the GMP requirements

    2. Surface finish must be smooth with low average roughness (Ra) value to avoid powder adherence

    3. Material transitions ground smooth to avoid powder adherence

    4. Inside corners have a generous radius to avoid powder adherence

  6. The chart on page 12 is empty. What kind of Features / Requirements have to be responded and rated there?  That chart is meant to be filled out by the respondent using the requirements/specifications in Section 2.3.  This allows you to break up or group the requirements as necessary to tailor your response to your particular proposal.  Sorry for any confusion.

  7. Page 13 (5.4 Estimated Project Cost): What kind of costs must be listed here? Do we have to specify an hourly rate and the expected expenditure of time for the development and creation of a prototype? Or do we have to estimate the total project cost until the commercialization of the product? What kind of detail information are required here?   The costs are the costs to deliver what you are proposing to deliver in response to the RFP. You should provide information related to the total project cost, the fixed price cost to be charged to ETC, and any investment your company is putting toward the project in US Dollars.  It is important the cost to ETC is a fixed price to provide the ETC members budget certainty.  For the purposes of the RFP you can give a price range but ETC will require a fixed cost to be determined through scoping and finalization of a Statement of Work before the project is started. 

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