Uniformity of Dosage Units in Pharmaceutical Analysis

To ensure the consistency of dosage units, it is crucial that each unit in a batch contains a drug substance content that falls within a narrow range around the label claim. Dosage units are dosage forms that hold a single dose or a portion of a dose of the drug substance in each unit. It is important to note that the specification for uniformity of dosage units does not apply to suspensions, emulsions, or gels in unit-dose containers that are intended for external, cutaneous administration.

Uniformity of dosage units refers to the consistency of the drug substance amount in each dosage unit. As such, the guidelines pertain to every drug substance found in dosage units containing one or more drug substances, unless explicitly stated otherwise in the Pharmacopeia.

The consistency of dosage units can be shown through one of two methods:

• Content Uniformity

  • may be applied in all cases

  • Learn how to perform content uniformity analysis and calculate the the acceptance value here.

• Weight Variation

  • applicable to the following dosage forms:

    • W1 - solutions enclosed in unit-dose containers and into soft capsules

    • W2 - solids (including powders, granules, and sterile solids) that are packaged in single-unit containers and contain no active or inactive added substances

    • W3 - solids (including sterile solids) that are packaged in single-unit containers, with or without active or inactive added substances, that have been prepared from true solutions and freeze-dried in the final containers and are labeled to indicate this method of preparation

    • W4 - hard capsules, uncoated tablets, or film-coated tablets, containing 25mg or more of a drug substance comprising 25% or more, by weight, of the dosage unit or, in the case of hard capsules, the capsule contents, except that uniformity of other drug substances present in lesser proportions is demonstrated by meeting the requirements for Content Uniformity

  • Learn how to perform weight variation analysis and calculate the acceptance value here

The table below can also be used as a reference to determine the method to use:

Reference: USP <905> Uniformity of Dosage Units

To demonstrate uniformity of dosage units, one must calculate the acceptance value using the formula |M-X| + ks, with the terms defined in Table 2 below:

Reference: USP <905> Uniformity of Dosage Units

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Reference:

USP <905> Uniformity of Dosage Units