905 UNIFORMITY OF DOSAGE UNITS
[noteIn this chapter, unit and dosage unit are synonymous.]
To ensure the consistency of dosage units, each unit in a batch should have a drug substance content within a narrow range around the label claim. Dosage units are defined as dosage forms containing a single dose or a part of a dose of drug substance in each unit. The uniformity of dosage units specification is not intended to apply to suspensions, emulsions, or gels in unit-dose containers intended for topical administration.
The term uniformity of dosage unit is defined as the degree of uniformity in the amount of the drug substance among dosage units. Therefore, the requirements of this chapter apply to each drug substance being comprised in dosage units containing one or more drug substances, unless otherwise specified in the individual monograph.
The uniformity of dosage units can be demonstrated by either of two methods, Content Uniformity or Weight Variation (see Table 1). The test for Content Uniformity is based on the assay of the individual content of drug substance(s) in a number of individual dosage units to determine whether the individual content is within the limits set. The Content Uniformity method may be applied in all cases. The test for Content Uniformity is required for those dosage forms described in (C1)(C6) below:
The test for Weight Variation is applicable for the following dosage forms:
The test for Content Uniformity is required for all dosage forms not meeting the above conditions for the Weight Variation test. Where compliance with the Content Uniformity test is required, then, by application of the provision for use of alternative methods provided in the General Notices section of this Pharmacopeia, it is possible for manufacturers to ensure this compliance by application of the Weight Variation test where the concentration relative standard deviation (RSD) of the drug substance in the final dosage units is not more than 2%. This RSD determination may be based on the manufacturer's process validation and product development data. The concentration RSD is the RSD of the concentration per dosage unit (w/w or w/v), where concentration per dosage unit equals the assay result per dosage unit divided by the individual dosage unit weight. See the RSD formula in Table 2. Where the Weight Variation test is used in this way, the product must, if tested, nevertheless comply with the official compendial test for Content Uniformity.
Table 1. Application of Content Uniformity (CU) and Weight Variation (WV) Tests for Dosage Forms
CONTENT UNIFORMITY Select not fewer than 30 units, and proceed as follows for the dosage form designated. Where the amount of drug substance in a single dosage unit differs from that required in the Assay, adjust the degree of dilution of the solutions and/or the volume of aliquots so that the concentration of the drug substances in the final solution is of the same order as that obtained in the Assay procedure; or, in the case of a titrimetric assay, use a titrant of a different concentration, if necessary, so that an adequate volume of titrant is required (see Titrimetry 541); see also Procedures under Tests and Assays in the General Notices and Requirements. If any such modifications are made in the Assay procedure set forth in the individual monograph, make the appropriate corresponding changes in the calculation formula and titration factor.
Where a special Procedure for content uniformity is specified in the test for Uniformity of dosage units in the individual monograph, make any necessary correction of the results obtained as follows.
Uncoated, Coated, or Molded Tablets, Capsules, Oral Solutions in Unit-Dose Containers, Suspensions or Emulsions or Gels in Single-Unit Containers (that are intended for systemic administration only), and Solids (including Sterile Solids) in Single-Unit Containers
Assay 10 units individually as directed in the Assay in the individual monograph, unless otherwise specified in the Procedure for content uniformity in the individual monograph. Calculate the acceptance value as directed below.
For oral solutions in unit-dose containers, and for suspensions, emulsions, or gels in single-unit containers that are intended for systemic administration only, conduct the Assay on the amount of well-mixed material that drains from an individual container in not more than 5 seconds, or for highly viscous products, conduct the Assay on the amount of well-mixed material that is obtained by quantitatively removing the contents from an individual container, and express the results as the delivered dose.
Calculation of Acceptance Value
Calculate the acceptance value by the formula:
in which the terms are as defined in Table 2.
Table 2
Suppositories, Transdermal Systems, and Inhalations Packaged in Premetered Dosage Units
[noteAcceptance value calculations are not required for these dosage forms.] Assay 10 units individually as directed in the Assay in the individual monograph, unless otherwise specified in the Procedure for content uniformity.
WEIGHT VARIATION Select not fewer than 30 dosage units, and proceed as follows for the dosage form designated. The result of the Assay, obtained as directed in the individual monograph, is designated as result A, expressed as % of label claim (see Calculation of Acceptance Value). Assume that the concentration (weight of drug substance per weight of dosage unit) is uniform. [noteSpecimens other than these test units may be drawn from the same batch for assay determinations.]
Uncoated or Film-Coated Tablets
Accurately weigh 10 tablets individually. Calculate the drug substance content, expressed as % of label claim, of each tablet from the weight of the individual tablet and the result of the Assay. Calculate the acceptance value.
Hard Capsules
Accurately weigh 10 capsules individually, taking care to preserve the identity of each capsule. Remove the contents of each capsule by a suitable means. Accurately weigh the emptied shells individually, and calculate for each capsule the net weight of its contents by subtracting the weight of the shell from the respective gross weight. Calculate the drug substance content, expressed as % of label claim, of each capsule from the net weight of the individual capsule content and the result of the Assay. Calculate the acceptance value.
Soft Capsules
Accurately weigh 10 intact capsules individually to obtain their gross weights, taking care to preserve the identity of each capsule. Then cut open the capsules by means of a suitable clean, dry cutting instrument such as scissors or a sharp open blade, and remove the contents by washing with a suitable solvent. Allow the occluded solvent to evaporate from the shells at room temperature over a period of about 30 minutes, taking precautions to avoid uptake or loss of moisture. Weigh the individual shells, and calculate the net contents. Calculate the drug substance content, expressed as % of label claim, in each capsule from the net weight of product removed from the individual capsules and the result of the Assay. Calculate the acceptance value.
Solids (Including Sterile Solids) in Single-Unit Con tainers
Proceed as directed for Hard Capsules, treating each unit as described therein. Calculate the acceptance value.
Oral Solutions Packaged in Unit-Dose Containers
Accurately weigh the amount of liquid that drains in not more than 5 seconds from each of 10 individual containers. If necessary, compute the equivalent volume after determining the density. Calculate the drug substance content, expressed as % of label claim, in the liquid drained from each unit from the net weight of the individual container content and the result of the Assay. Calculate the acceptance value.
Calculation of Acceptance Value
Calculate the acceptance value as shown in Content Uniformity, except that the individual contents of the units are replaced with the individual estimated contents defined below.
Solutions for Inhalation Packaged in Glass or Plastic Ampuls and Intended for Use in Nebulizers
[noteAcceptance value calculations are not required for these dosage forms.] Accurately weigh 10 containers individually, taking care to preserve the identity of each container. Remove the contents of each container by a suitable means. Accurately weigh the emptied containers individually, and calculate for each container the net weight of its contents by subtracting the weight of the container from the respective gross weight. From the results of the Assay, obtained as directed in the individual monograph, calculate the drug substance content, expressed as % of label claim, in each of the containers.
CRITERIA Apply the following criteria, unless otherwise specified in the individual monograph.
Uncoated, Coated, or Molded Tablets, Capsules, Oral Solutions in Unit-Dose Containers, Suspensions or Emulsions or Gels in Single-Unit Containers (that are intended for systemic administration only), and Solids (including Sterile Solids) in Single-Unit Containers
The requirements for dosage uniformity are met if the acceptance value of the first 10 dosage units is less than or equal to L1%. If the acceptance value is greater than L1%, test the next 20 units, and calculate the acceptance value. The requirements are met if the final acceptance value of the 30 dosage units is less than or equal to L1%, and no individual content of any dosage unit is less than [1 (0.01)(L2)] M nor more than [1 + (0.01)(L2)] M as specified in the Calculation of Acceptance Value under Content Uniformity or under Weight Variation. Unless otherwise specified in the individual monograph, L1 is 15.0 and L2 is 25.0.
Suppositories
Limit A
(if the average of the limits specified in the potency definition in the individual monograph is 100.0 percent or less)Unless otherwise specified in the individual monograph, the requirements for dosage uniformity are met if the amount of the drug substance in each of the 10 dosage units as determined from the Content Uniformity method lies within the range of 85.0% to 115.0% of the label claim, and the RSD is less than or equal to 6.0%.
If 1 unit is outside the range of 85.0% to 115.0% of label claim, and no unit is outside the range of 75.0% to 125.0% of label claim, or if the RSD is greater than 6.0%, or if both conditions prevail, test 20 additional units. The requirements are met if not more than 1 unit of the 30 is outside the range of 85.0% to 115.0% of label claim, and no unit is outside the range of 75.0% to 125.0% of label claim and the RSD of the 30 dosage units does not exceed 7.8%.
Limit B (if the average of the limits specified in the potency definition in the individual monograph is greater than 100.0 percent)
Transdermal Systems and Inhalations Packaged in Premetered Dosage Units
Limit A
(if the average of the limits specified in the potency definition in the individual monograph is 100.0 percent or less)Unless otherwise specified in the individual monograph, the requirements for dosage uniformity are met if the amount of the drug substance in not fewer than 9 of the 10 dosage units as determined from the Content Uniformity method (or, in the case of solutions for inhalation packaged in glass or plastic ampuls and intended for use in nebulizers, from either the Content Uniformity or the Weight Variation method) lies within the range of 85.0% to 115.0% of label claim, and no unit is outside the range of 75.0% to 125.0% of label claim, and the RSD of the 10 dosage units is less than or equal to 6.0%.
If 2 or 3 dosage units are outside the range of 85.0% to 115.0% of label claim, but not outside the range of 75.0% to 125.0% of label claim, or if the RSD is greater than 6.0% or if both conditions prevail, test 20 additional units. The requirements are met if not more than 3 units of the 30 are outside the range of 85.0% to 115.0% of label claim and no unit is outside the range of 75.0% to 125.0% of label claim, and the RSD of the 30 dosage units does not exceed 7.8%.
Limit B
(if the average of the limits specified in the potency definition in the individual monograph is greater than 100.0 percent)
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USP32NF27 Page 382
Pharmacopeial Forum: Volume No. 34(5) Page 1290
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