1. Approach 1 (Dose criterion)
No more than 0.1% of the normal therapeutic dose of one product will appear in the maximum daily dose of a subsequent product.

2. Approach 2 (10 ppm criterion)
No more than 10 ppm of one product will appear in another product

3. Approach 3 (Visually clean criterion)
(No residue should be visible on equipment after cleaning.)
Spiking studies should determine the concentration at which most active ingredients are visible. This criterion may not be suitable for high potency, low-dosage drugs.

The acceptance limit calculation for chemical residue shall be based on Dose Criteria and 10 ppm Criteria. Minimum value obtained among these two criterions shall be selected as L1. The calculation for Dose and 10 ppm criteria is given as below.

As per dose criteria
There have been a number of examples of industry guidance documents implementing some form of the toxicology based approach proposed by Dr. Hall.

NOEL(No observed effect level) is amount of drug in mg that does not have any effect on human health.

NOEL= LD50 X 70 KG/2000

LD50     = Lethal Dose for 50% of animal population in study
NOEL = No observed effect level
70Kg   = Average adult dose
2000    =Constant

Now NOEL used to calculate Maximum Allowable Carry Over (MACO).


NOEL = No observed effect level
MBS   = Maximum batch size
TDD   = Total daily dose
SF       =Safety factor
(A)      = Previous product
( B)     = Incoming Product

As per 10 ppm criteria

                         Minimum therapeutic dose of product A X safety Factory
MACO (L1)      =---------------------------------------------------------------
                                              Maximum daily dose of product B

L1= 10 mg of product A per Kg of product B

MACO limit of product A into total batch size of the Product B (L2) shall be calculated as per below formulae;

            L2= L1 X minimum batch size of product B

MACO limit of product A per sq cm surface area (L3) shall be calculated by using following formulae;

L3=  ---------------------------------------------------------------
   Cumulative product contact surface area of the equipments

MACO limit of product A per swab area (L4) shall be calculated as per following formulae;

L4= L3X swab area (cm2)

MACO limit of product A per rinse (L4) shall be calculated as per following formulae;

                         (L3) X (area rinsed)
L4(Rinse) = ----------------------------------------
                        (Amount of rinsing solvent)

Bracketing by equipment should be done only when it is similar equipment, or the same equipment in different sizes (e.g. 300-L, 500-L and 1000-L tanks). An alternative approach may be to validate the smallest and the largest sizes separately.

The worst case for a group of equipment is represented by the equipment with the larger product contact surface and the hardest-to-clean locations.

Only one product out of a group of product processed in a piece of equipment is selected for the cleaning validation study, based on the lowest solubility of the active ingredient and its therapeutic dose.

The objective for establishing time limit between equipment cleaning and reuse is to ensure that the equipment remains clean till the next use. This needs demonstration that there is no microbial proliferation in cleaned equipments during storage.

For establishing the time limit, the equipment should be dried. Initial swab samples for surface should be taken. Thereafter, the equipment should be protected as prescribed in the SOP and stored in its designated area. Periodic samples of product contact surface for microbiological contamination should be taken. (1st day, 2nd day, 3rd day etc.)

Based on the data generated establish the acceptable time limit.

There are many analytical techniques available that can be used in cleaning validation

The Basic Requirements for the Analytical Method.

1. The sensitivity of the method shall be appropriate to the calculated contamination limit.
2. The method shall be practical and rapid, and, as much as possible use instrumentation existing in the company.
3. The method shall be validated in accordance with ICH, USP and EP requirements.
4. The analytical development shall include a recovery study to challenge the sampling and testing methods.

  • Chromatographic methods such as GC, HPLC etc.
  • Thin layer chromatography
  • Specific ion meter

Of the above methods, chromatography methods are the methods of choice, as they separate analytes, are highly specific, highly sensitive, and quantitative. But the methods are costly and time consuming.

  • Spectrophotometric methods in the visible, infrared, or UV ranges
  • Total organic carbon (TOC)
  • Other Methods

For monitoring cleaning procedure TOC method is used. It offers at a moderate cost and in addition to its rapidity, a detection capability down to the ppb range.

  1. Detailed cleaning procedure(s) are to be documented in SOPs.
  2. A Cleaning Validation Protocol is required to define how the cleaning process will be validated.

It should include the following:

  • The objective of the validation process.
  • Responsibilities for performing and approving the validation study.
  • Description of the equipment to be used.
  • The interval between the end of production and the beginning of the cleaning procedure.
  • The number of lots of the same product, which could be manufactured during a campaign before a full cleaning is done.
  • Detailed cleaning procedures to be used for each product, each manufacturing system or each piece of equipment.
  • The number of cleaning cycles to be performed consecutively.
  • Any routine monitoring requirement.
  • Sampling procedures, including the rationale for why a certain sampling method is used.
  • Clearly defined sampling locations.
  • Data on recovery studies where appropriate.
  • Validated analytical methods including the limit of detection and the limit of quantitation of those methods.
  • The acceptance criteria, including the rationale for setting the specific limits;
  • Other products, processes, and equipment for which the planned validation is valid according to a “bracketing” concept.
  • Change Control/ Re-validation.
  1. Depending upon the complexity of the system and cleaning processes, the amount of documentation necessary for executing various cleaning steps or procedures may vary.
  2. When more complex cleaning procedures are required, it is important to document the critical cleaning steps. In this regard, specific documentation on the equipment itself which includes information about who cleaned it, when the cleaning was carried out, the product which was previously processed on the equipment being cleaned should be available. However, for relatively simple cleaning operations, the mere documentation that the overall cleaning process was performed might be sufficient.
  3. Other factors such as history of cleaning, residue levels found after cleaning, and variability of test results may also dictate the amount of documentation required. For example, when variable residue levels are detected following cleaning, particularly for a process that is believed to be acceptable, one must establish the effectiveness of the process and of the operator performance. Appropriate evaluations must be made, and when operator performance is deemed a problem, more extensive documentation (guidance) and training may be required.
  4. A Final Validation Report should be prepared. The conclusions of this report should state if the cleaning process has been validated successfully. Limitations that apply to the use of the validated method should be defined (for example, the analytical limit at which
  5. cleanliness can be determined). The report should be approved by management.


A change control system is in place to ensure that all changes that might impact the cleaning process are assessed and documented. Significant changes should follow satisfactory review and authorization of the documented change proposal through the change control procedure. Minor changes or changes having no direct impact on final or in-process product quality should be handled through the documentation system.

Revalidation shall be carried out in case of following;

  1. If the solubility of the new product being added is less than the previously considered worst-case product.
  2. If the potency of the new drug is lower than the previous worst case product.
  3. Change or any major modification to the equipment, which has significant effect on the contact surface area.
  4. Change in cleaning agent or its concentration wherever applicable.
  5. Change in cleaning procedure (SOP).
  6. Failure during routine monitoring.

A validation report is necessary to present the results and conclusions and secure approval of the study.

The report should include the following:

  1. Summary of or reference to the procedures used to clean, sample and test.
  2. Physical and analytical test results or references for same, as well as any pertinent observations.
  3. Conclusions regarding the acceptability of the results, and the status of the procedure(s) being validated.
  4. Any recommendations based on the results or relevant information obtained during the study including revalidation practices if applicable.
  5. Approval of conclusions.
  6. Review any deviations for the protocol that occurred.
  7. In cases where it is unlikely that further batches of the product will be manufactured for a period of time it is advisable to generate interim reports on a batch by batch basis until such time as the cleaning validation study has been completed.


  1. FDA expects firms to have written standard operating procedures (SOP) detailing the cleaning  process used for various pieces of  equipment.
  2. If firms have a specific cleaning process for cleaning between different batches of the same product and use a different process  for cleaning between product changes, FDA expects the written procedures to address these different scenarios.
  3. If firms have one process for removing water-soluble residues and another process for non-water soluble residues, the written procedure should address both scenarios and make it clear when a given procedure is followed.
  4. It is required by the FDA, in the general validation procedure, that the personnel responsible for performing and approving the study should comply with the acceptance criteria and the revalidation data.
  5. FDA expects firms to prepare specific written validation protocols in advance for the studies to be performed on each manufacturing system or piece of equipment which should address such issues as sampling procedures, and analytical methods to be used including the sensitivity of those methods.
  6. It is expected that firms conduct the validation studies in accordance with the protocols and document the result of studies.
  7. Final validation report is to be approved by the regulatory board which states whether or not the cleaning process is valid.

There is practically impossible to prove that production equipment is “clean” at the level of 100%. However, it is possible to prove that the traces of active product remaining spread through the equipment parts are within an acceptable limit and that we are capable of detecting and quantifying these trace levels. A cleaning validation program should contain the assessment of equipment and products, assessment of the impact of a process on routine process, determination of an appropriate cleaning agent and method, determination of acceptance criteria for the residues, determination of a degree of evaluation required to validate the procedure, This article contain a defined cleaning validation program.

2. Health products and food branch inspectorate guidance document cleaning validation  guidelines guide-0028; 2008
3. Parenteral drug association, Points to consider for cleaning validation, technical report no. 29, 1998.
4. Galatowitsch S; The importance of cleaning validation. Clean rooms; 2000
5. Babita Lodhi, Poonam Padamwar, Arif Patel; Cleaning validation for the pharmaceuticals, biopharmaceuticals, cosmetic and neutraceuticals industries, Journal of Innovations in Pharmaceuticals and  Biological Sciences; 2014; 1(1); 27 - 38
6. Anindya Ghosh; Review article overview of cleaning validation in pharmaceutical industry; International journal of pharmaceutical quality assurance; 2010; 2(2); 26-30.
7. S. Lakshmana prabu; Cleaning validation and its importance in pharmaceutical industry; pharma times; 2010; 42(7); 21-25
8. FDA, guide to inspections of validation of cleaning process division of investigations, office of regional operations & office regulatory affairs, 1993.
9. Jenkins M; Cleaning validation; an overall perspective; Pharm tech, 1994; 18(4); 60-73.
10. Hyde JM; Cleaning validation strategies, ISPE CIP/SIP seminar, Atlanta-Georgia, 1994
11. Leblanc DA; Rinse sampling for cleaning validation studies; Pharm tech. 1998.
12. Fourman GL; Determining cleaning validation acceptance limits for pharmaceutical manufacturing operations; Pharm tech;1993; 17(4); 54.
13. Vitale KM; Cleaning validation acceptance criteria.; 15th annual pharm tech conference, east brunswi new jersey;1995.
14. Heinig K; Determination of linear alkylbenzene-sulfonates in industrial and environ-mental sample by capillary electro-phoresis; 1998; 123(2); 349- 353



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