Updates for Quality and Performance Testing of Mucosal Drug Products: USP Viewpoint

Posted May 5, 2016

Late last year, I had the opportunity to attend the USP Network where discussions were focused on testing procedures for topical drug products, particularly mucosal drug products.

New USP testing procedures and recommendations for non-standardized procedures for the testing of mucosal drug products were discussed. Below is a summary of some key points covered at the USP Network conference which you should be aware of before testing a mucosal drug.

In general, critical quality attributes of mucosal drugs are assessed by product quality tests and product performance tests. Product quality tests are used for the assessment of physical, chemical and microbiological attributes, whereas product performance tests are used for the assessment of in vitro drug release.

There are seven routes of application for mucosal drug products, as shown below:

Mucosal dosage routesProduct quality tests for mucosal dosage forms that previously have been discussed in Pharmacopeial Forum, General Chapters <4> became official with USP 38 since May 1, 2015. These product quality tests are necessary in order to determine the drug product specifications. The following information in terms of the drug substance(s) present in the dosage form must be determined: 

  • Identification
  • Assay for impurities
  • Uniformity of dosage units

For example, for Benzocaine Otic Solution (a mucosal drug with an otic route of application), USP requires three tests:

  1. Definition
  2. Identification
  3. Assay for impurities.

Additionally, dose- and route-specific tests include microbial tests <61> and <62>. Other routes of application for mucosal drug products that follow similar testing are as follows:

  • Ophthalmic
  • Nasal
  • Oro-Pharyngeal
  • Vaginal
  • Rectal

Interestingly, there is a need to clarify suppositories versus inserts. Suppositories are defined as dosage forms that are adapted for application into the rectum or vagina (general chapter <1151>), for example Miconazole Nitrate Vaginal Suppositories. In comparison, inserts are solid dosage forms that are inserted into a naturally occurring (nonsurgical) body cavity other than the mouth or rectum, for example Clindamycin Phosphate Vaginal Inserts.

It should be noted that for mucosal drug products that are applied via the urethral route, for example, Alprostadil Urethral Suppository Transurethral System, there is no USP monograph.

With regards to performance tests for mucosal dosage forms, which are described in general chapter <1004>, some of the approaches that have been introduced are new to USP and therefore need extra consideration.

Apparatuses that are described in Performance Tests for Mucosal Dosage Forms are described in general chapter <1004>. Some approaches introduced are new to USP and considerable attention needs to be paid to them.

The apparatuses that are described in USP chapters include:

  • USP Apparatus 1, 2, 3, 4 <711> covers
  • Inserts
  • Sublingual and Buccal Tablets
  • Suppositories
  • Lozenges
  • Hydrophilic Suppositories
  • USP Apparatus 5 <724> is good for films

There are numerous testing apparatuses/procedures that have been already designed and routinely use in industry, but these are not yet standardized and proposed in USP. The publication by Marques et al. (1) gives recommendations for what should be used in these situations.  For instance, for the testing medicated gums it is recommended that dissolution apparatus testing with Palmieri basket is used. For suppositories, it is recommended that a small-volume dissolution system is used, such as a mini paddle/basket. As Marques is head of this particular division of USP, these recommendations can be considered as temporary guidance for what tests should be used in this situation.

Have a question about mucosal drug produts? Contact Neil Holman to discuss your testing needs - or 1-905-625-7995 x 116.


1. Marques MRC, Loebenberg R, Almukainzi M. Simulated biological fluids with possible application in dissolution testing. Dissolution Technologies. 2011;18(3):15–28

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