This Editorial Guide is used for Education Purposes Only. It is used in the Authoring Courses and Certifications. It is based on the January 2026 Editorial Guide.

Medicinal Product model diagrams

The diagrams below show the overall basic medicinal product model. Note that in each diagram, no role, structure, or disposition grouper concepts are shown. Definitions and detailed descriptions are given in the sections following this overall model introduction.

MP classes = shades of blue

MPF classes = shades of yellow

CD class = green

This first diagram is a class model illustrating the five classes of concepts in the model and the relationships between them, in their three groups (MP, MPF and CD) plus an additional optional sixth sub-class to be populated in limited cases and likely in national extensions only (MP Precise Only). Two classes use the existential restriction (MP and MPF) and four use the (proxy for the) universal restriction (MP only, MPF only, CD and MP Precise Only). MP Precise Only is the optional sub-class that represents a product described explicitly and only by its precise active ingredient substances, i.e. including clinically significant modification such as "dexamethasone sodium phosphate ".

Figure: Medicinal Product concept model - International edition

The next diagram below is in SNOMED notation (inferred view), and shows only the five classes that will be populated in the international release, at least for the foreseeable future. The Medicinal Product model is parented by the proximal primitive 763158003 |Medicinal product (product)| concept, an abstract concept representing an item that "has been formulated and manufactured for administration to humans (or animals) for treatment or prevention of disease, for diagnosis of illness or to restore, correct or modify physiological function and which contains an active ingredient substance or combination of substances". This parent concept acts both to scope the domain and, in the future, will separate medicinal products from other products in a larger Products hierarchy, which may include medical devices and certain other products such as foods and cosmetics.

The last model diagram below shows multi-ingredient medicinal products, and therefore, has increased complexity. It again shows the three groups (MP, MPF and CD) with MP classes shown in shades of blue, MPF classes in shades of yellow and the CD class in green; each with two single active ingredient representations (X and Y) and one multi-ingredient representation (X + Y) and then the relationships between these. It shows how the single ingredient "containing" classes (the open world classes) subsume the appropriate multi-ingredient class, whereas the single ingredient "containing only" classes (the closed world classes) do not subsume the multi-ingredient class. The optional MP Precise Only class is present but is not shown with any multi-ingredient products, to limit complexity. MP Precise Only multi-ingredient products are discussed later in the Ingredient Count Attributes.

Provide Feedback

This Editorial Guide is used for Education Purposes Only. It is used in the Authoring Courses and Certifications. It is based on the January 2026 Editorial Guide.

When authoring in this domain, these are the approved attributes and allowable ranges.

Domain Information for Pharmaceutical/Biologic Product

This Editorial Guide is used for Education Purposes Only. It is used in the Authoring Courses and Certifications. It is based on the January 2026 Editorial Guide.

Examples: vials, ampoules, sachets, containing solid dose forms such as powders or granules which may or may not be dissolved before administration

The unit of presentation usually either uses the same word (even though it is a different concept) as the (package item) container, or the (package item) container is a more granular concept and the unit of presentation uses a less granular term. Strength is expressed as "per one unit of presentation" and the presentation strength and the concentration are exactly the same.

Example: Pack of 10 vials each containing 2g cefotaxime powder for solution for injection

This Editorial Guide is used for Education Purposes Only. It is used in the Authoring Courses and Certifications. It is based on the January 2026 Editorial Guide.

The following sections describe the attribute concepts that are used to represent the ingredient counts for all concepts represented using the "closed world view" (the "only" and "precisely" concepts) in the medicinal product hierarchy.

Ingredient Count

Ingredient count is the mechanism that the SNOMED CT concept model is using as a proxy to implement a "closed world" view of medicinal products such that a medicinal product concept can be represented as containing only substance X as its active ingredient, and that all more granular child medicinal product concepts also containing only substance X subsume under the correct parent concept(s).

Three count attributes are available for use, but only one is mandatory for all only concepts; i.e. MP (only), MP (precisely), MPF (only) and CD). The additional ingredient counts have to be applied iteratively, if and when they are required based on the presence of multi-ingredient concepts which contain active ingredient substances that have modifications of the same base. For new concepts, the count attribute is first authored for Clinical Drug concepts, which have their precise ingredient substance described; the more abstract classes can then be populated upwards using the base (or parent) active ingredient substance if different.

This count is the number of base (or root or main parent) active ingredient substance(s) (as described in the SNOMED CT Substance hierarchy) present in the medicinal product. Base ingredient substances can be identified from their modifications through the relation "is modification of", traversed iteratively if necessary, until reaching a substance that is not a modification of any other substance.

For all single ingredient products and for the majority of multi-ingredient products, this is the only count information that needs to be described in order to support correct subsumption.

For simplicity, all the intermediate medicinal product form concepts have been omitted from the diagrams and examples.

Example:

The tooling uses these values to produce the correct subsumption hierarchy, as shown diagrammatically below:

Figure: Ingredient count attributes simple multi-ingredient example

The base count facilitates the correct subsumption relationship between the "Product containing only amlodipine and atorvastatin" and the clinical drug that contains only amlodipine and atorvastatin. It avoids the "Product containing only amlodipine and atorvastatin" being incorrectly subsumed by the concept "Product containing only amlodipine" or by the concept "Product containing only atorvastatin" since a concept of a base count of 1 will not subsume a product with a base count of 2. Similarly the clinical drug concepts containing only amlodipine or only atorvastatin, both of which have a base count of 1, are prevented from being subsumed by the "Product containing only amlodipine and atorvastatin" which has a base count of 2.

This count is used for multi-ingredient products where the two (or more) active ingredient substances share the same base active ingredient substance. This will only occur when at least one of the active ingredient substances is a modification of a base active ingredient substance. The count used in addition to the base active ingredient substance count. The count is of how many pairs of base + modification substances are present in the medicinal product; this draws from the Substance hierarchy where concepts are managed using the pattern of base substance with related concepts being modifications (salts, esters, chelates) of the base substance; each modification is therefore a "pair".

For example,

Betamethasone sodium phosphate and betamethasone acetate are both modifications of the betamethasone: a phosphorylation and an acetate esterification; however neither are modifications of each other.

The tooling uses these values to produce the correct subsumption hierarchy, as shown diagrammatically below:

Base count alone would not prevent the incorrect subsumption of the "Clinical drug containing precisely betamethasone sodium phosophate and betamethasone acetate" to the parent medicinal product concepts containing only betamethasone sodium phosophate (or only betamethasone acetate - not shown on the above diagram). By adding in the Count of base + modification pair, that incorrect subsumption is avoided and the "Clinical drug containing precisely betamethasone sodium phosophate and betamethasone acetate" is correctly subsumed by just the one parent medicinal product - that "containing only betamethasone sodium phosophate and betamethasone acetate". The (grand)parent medicinal product concept "Product containing only betamethasone" does not (cannot) have a Count of base + modification pair, since it does not have any active ingredient modification described; therefore it can correctly parent medicinal product concepts containing only betamethasone sodium phosophate, containing only betamethasone acetate (not shown) and containing "only betamethasone sodium phosophate and betamethasone acetate", because they all share a base count of 1, relating to betamethasone.

This count is used for the fairly rare cases of multi-ingredient products where the two (or more) precise active ingredient substance(s) share the same base active ingredient substance and one of those precise active ingredient substances is a modification of another; it is used in addition to the base count and the base + modification pair count. The count is of how many precise active ingredient substance(s) are present in the product (and therefore can be a count of the number of precise active ingredient attributes are present on a concept).

For example,

Insulin aspart and insulin aspart protamine are both modifications of insulin; but since Insulin aspart protamine is itself a modification of Insulin aspart, the Base + modification pair count is only equal to 1 (insulin plus 1 modification - the aspart). To get correct subsumption between the Clinical Drug and Medicinal Product concepts in these types of situations, the third count, that of precise active ingredient substance, must be used as well.

The tooling uses these values to produce the correct subsumption hierarchy, as shown diagrammatically below:

Neither base count alone nor base count and base + modification pair count would prevent the incorrect subsumption of the "Clinical drug containing precisely insulin aspart and insulin aspart protamine" because both give a count of 1. The differentiation comes from the counting the precise active ingredient substances. This then gives the (optional in the international release) intermediate parent concepts of "Medicinal product containing precisely" either "insulin aspart", "insulin aspart protamine" or "insulin aspart and insulin aspart protamine" with their correct clinical drug concepts as children. The MP (precisely) concepts are then correctly subsumed to the (grandparent) MP (only) concept of insulin aspart only, on the basis of the base count of 1.

This Editorial Guide is used for Education Purposes Only. It is used in the Authoring Courses and Certifications. It is based on the January 2026 Editorial Guide.

The following sections describe the attribute concepts used to represent the ingredient strength of concepts in the medicinal product hierarchy.

Describing Medicinal Product Strength - Presentation and Concentration Strength

"Medicinal product strength" is not well defined in standards. It is closely aligned with "potency" which in pharmacology describes the measurement or calculation of the therapeutic activity of the medicine; this is expressed in terms of the amount of medicine required to produce an effect of given intensity. Strength is a ratio type concept: expressing the amount of something against another amount of something, which in practical terms is expressed fractionally using the numerator and denominator quantities and their relevant units. The numerator represents how much of the active ingredient substance there is, and the denominator represents the "whole" that the numerator amount is present in. For a medicinal product, therefore, the strength is:

the amount of (active) substance (in the form of) the basis of strength substance** in one instance of "a whole" of medicinal product**

It is the "one instance of "a whole" of medicinal product " that causes the difficulty. It is not possible to have a single pattern for what this means for all types of medicinal products. Therefore, the consensus for all medicinal product terminology is to define the pattern for each type of product and apply it consistently. In addition, because historically, there has been a difference in how to develop and apply these patterns, a differentiation has developed between two types of representation "presentation strength" and "concentration strength", which are best expressed explicitly.

Presentation strength

Presentation strength is the amount of the basis of strength substance present in the unit of presentation of or in the volume (or mass) of the single clinical drug being represented.

Concentration strength

Concentration strength is the amount of the basis of strength substance present per unitary amount (volume, mass) of the single clinical drug being represented.

These two options may be used separately, as they are in this international model specification but can also be used together (as may be used in national extensions), thereby producing three patterns for how medicinal product strength can be described. The place of unit of presentation to provide the "bounding" and to support the description of "a whole" for the medicinal product is described in detail in its own section below.

Description of strength is a safety issue. Mindful that SNOMED CT international edition is primarily a reference terminology not an interface terminology, it is still important that the description of product strength should be that which is least confusing for national extensions to use and build out from. Presentation strength is deemed by patient safety agencies to be the least confusing for the majority of types of products so should be provided whenever possible. However, to avoid combinatorial explosion and to have realistic maintenance processes for the international edition content, some types of products that could be described with both presentation and concentration strength will be described with concentration strength only.

Clinical drug concepts using pattern 1 will be present in the international edition as will clinical drugs using strength pattern 3. Clinical drugs using strength pattern 2 may be authored in national extensions.

IDMP (and in particular (ISO 11615 section 9.7.2.4) is clear that strength "can be expressed in two ways: strength (presentation) and strength (concentration)" and it uses both in parallel within the standard. Presentation strength is generally required for description of manufactured items, whereas concentration strength may be optionally provided. When describing the strength of a pharmaceutical product that has undergone a transformation (e.g. dissolution or dispersion), the strength is specified as it would occur "when the transformation undertaken exactly in accordance with the regulated product information". It is not clear whether, if the regulated product information provides alternative transformations, more than one pharmaceutical product would be authored. Since the Medicinal Product model does not intend to represent a transformed product using the administrable dose form when this is different, primarily because of this type of uncertainty, this issue can be put aside. IDMP has the concept of "Reference Strength" to explicitly describe the difference between the precise active ingredient substance and the basis of strength substance, or to support description of strength in alternative units. The Medicinal Product model supports basis of strength substance explicitly, and therefore is compatible with IDMP, and because alternative descriptions (synonyms) are a core part of the SNOMED structure, alternative strength representations could be provided if required (e.g. adrenaline 1:1000 rather than 1 mg per mL).

See also the .

ISO 11615 in IDMP introduces the concept of "measurement point" for strength in some products, usually those with a metered dosage value system, for example, the strength of the active ingredient substance in some inhaler products, is measured at a particular distance from the point of aerosolisation. Using a strength measurement point is currently something that is country-specific (although regulation may change to make it more standardized as its use becomes more widespread). In the international core, it may become important to specify the measurement point for the strength of some products to allow national extensions to select the correct concept for their use, since it would appear that differences in measurement point between otherwise similar products can be clinically significant. Measurement point is currently not explicitly described in the international release.

This Editorial Guide is used for Education Purposes Only. It is used in the Authoring Courses and Certifications. It is based on the January 2026 Editorial Guide.

Examples: bulk powders and granules, bulk liquids, semi-solids

These presentations are not particularly bound by their container in any way that is meaningful in terms of their use or administration; the Manufactured Item is a continuous presentation and almost all are used in individually calculated and variable amounts.

For example,

• Hydrocortisone cream for cutaneous use is contained in a tube, but its use is based on how much is squeezed out and applied to the skin.

• Chloramphenicol eye drops are presented in a dropper bottle, but they are administered drop by drop and although the dropper bottle aims to deliver a roughly uniform sized drop to the eye, they are not "metered dose containers" in the way that containers with valves are.

A unit of presentation is not usually given for these products. The pack size (not relevant for SNOMED international model) is given as the Manufactured Item quantity. Strength is expressed as a concentration and as such the presentation strength and the concentration are exactly the same.

This Editorial Guide is used for Education Purposes Only. It is used in the Authoring Courses and Certifications. It is based on the January 2026 Editorial Guide.

Examples: oral solutions, suspensions, emulsions, syrups

This is a variation on the metered dose presentation; the unit of presentation supplied by the manufacturer to provide the “metered dose” is the 5mL spoonful, since this represents “the quantity of product that is administered by filling a single spoon administration device” [EDQM]. Strength is expressed as “per one unit of presentation” (per 5 mL [spoonful]) BUT the presentation strength and the concentration are NOT the same, since these are continuous liquids, so the concentration strength of “per 1 mL” will usually be a different value. Note that explicit representation of the medicine spoon would be as an administration device, and is therefore out of scope of the international Medicinal Product hierarchy. National extensions may wish to represent the inclusion of a medicine spoon (or indeed any other administration device such as an applicator) in the package description (as in IDMP, for example) should the use case(s) require.

Example: A bottle of 125 mL of aciclovir oral suspension 200mg/5mL

This Editorial Guide is used for Education Purposes Only. It is used in the Authoring Courses and Certifications. It is based on the January 2026 Editorial Guide.

Examples: bulk parenteral solutions, insulins, patches

The unit of presentation usually either uses the same word (even though it is a different concept) as the (package item) container, or the (package item) container is a more granular concept and the unit of presentation uses a less granular term. However, although presentation strength is expressed as "per one unit of presentation", the clinically relevant strength is the concentration strength, as almost all are used in individually calculated and variable amounts. Note that the unit of presentation is likely to be useful in description of the medicinal product concept at some level; insulin presented in a multi-dose vial will be used/administered differently from insulin presented in a cartridge for use within a "pen device".

Example: A pack of 5 cartridges each containing 1.5mL soluble human insulin 100 units/mL solution for injection

This Editorial Guide is used for Education Purposes Only. It is used in the Authoring Courses and Certifications. It is based on the January 2026 Editorial Guide.

Examples: various inhalers, nasal sprays, some cutaneous sprays/foams

The unit of presentation is the actuation, the “single operation of a metered-dose pump, valve or other equivalent dosing mechanism” [EDQM].

Strength is expressed as “per one unit of presentation” and the presentation strength and the concentration are exactly the same.

Example: Single inhaler containing a total of 200 actuations worth of salbutamol, 100 micrograms per actuation, packaged in a box

This Editorial Guide is used for Education Purposes Only. It is used in the Authoring Courses and Certifications. It is based on the January 2026 Editorial Guide.

The following sections discuss the attribute concepts used to represent the ingredient substances of concepts in the medicinal product hierarchy.

Ingredient Substances

Figure: Ingredient role attributes

The diagram above shows the relationship of the various attribute roles that a substance can play in the definition of MP, MPF and CD description of medicinal products. Any concept from the Substance hierarchy may play one or more of these roles within a product. In all of the descriptions below, when the phrase "a set of substances" is used, the set may have only one member.

Has ingredient

A medicinal product concept has a set of substances that are combined to manufacture the medicinal product that can be described using the "has ingredient" attribute. However, each substance(s) in the "has ingredient" set will have more specific ingredient role that should be described using that more specific concept. Therefore, this is a grouping concept that is not used for definition of medicinal product concepts in the medicinal product hierarchy; it is a parent concept and it provides scope for further child concepts to be added to support future use cases, such as the description of inactive/excipient ingredient substances in products in a national extension. The physical presence or otherwise of an ingredient substance in the finished product may not explicitly be necessary for it to be part of the product's substance description; for example substances that play a role in the manufacturing process, such as solvents etc. are deemed "ingredients" for the product; their presence may or may not remain in the manufactured item. As such, basis of strength substance could be considered as a child concept of the Has ingredient concept, although it is not modeled in that way currently.

A medicinal product concept has a set of active ingredient substance(s) responsible for providing the therapeutic effect of the medicinal product and which are described using the clinically relevant part or whole of the substance that is intended to have a therapeutic action on or within the body. In the majority of cases, this description excludes modifiers such as esters, salts or other non-covalent derivatives (such as a complex, chelate etc.), but may include them in the minority of cases when clinically significant (e.g. liposomal substances). This is therefore usually an abstract representation of the active ingredient substance(s) and is used in more abstract representations of medicinal products, such as MP (containing).

Note that "clinical significance" can be described as "something that has a practical, demonstrable effect on the treatment and condition of the patient". For example: different modifiers of a particular active moiety have clinical significance if they affect the potency of the therapeutic action of the moiety (and therefore have an affect on the dose quantities to be used). See Kazdin, E The Meanings and Measurement of Clinical Significance Journal of Consulting and Clinical Consulting 67 (3): 332–9. This is the attribute role that is used in the definition of the MP concept (containing and only) and the MPF concept. Examples of substances playing the role of active ingredient in a medicinal product:

• azithromycin where the precise active ingredient may be azithromycin hemiethanolate, azithromycin isopropanolate

• haloperidol where the precise active ingredient may be haloperidol hydrochloride, haloperidol decanoate, haloperidol lactate

• esomeprazole where the precise active ingredient may be esomeprazole magnesium, esomeprazole sodium

• oxybutynin where the precise active ingredient may be oxybutynin chloride or oxybutynin xinafoate

A medicinal product concept has a set of precise active ingredient substance(s), those substance(s) that provides the therapeutic effect of the medicinal product and which are described using the fullest and most specific description of the substance as it is used in the product(s) that the concept represents (as they are presented by the manufacturer in the manufactured dose form, before any dilution or transformation). The precise active ingredient substance may include various modifiers, such as salts, esters and/or polymers (e.g. pegylation); not all substances, even when used as the precise active ingredient substance, have a modification (see axitnitib). This is the attribute role that is used in the definition of the MP (precisely) concept, and in the definition of the CD (precisely). Examples:

• haloperidol decanoate

• oxybutynin chloride

• dexamethasone sodium phosphate

• sorafenib tosylate

The precise active ingredient attribute will use the Substance hierarchy as a flat list (without role chaining), so that a Clinical Drug containing a modified substance is not subsumed under a clinical drug containing the unmodified substance, thereby unintentionally adding more recursion to the clinical drug class (for example: so that a morphine (base) precise clinical drug does not subsume a clinical drug containing precisely morphine sulphate). This highlights the difference between the semantic of "contains precisely" which explicitly and exclusively describes the full modified substance in the medicinal product concept and "contains only" which inclusively describes the therapeutically active moiety which may be manifest in one or more substance modifications of itself.

Examples:

• "contains dexamethasone only" means that a product will contain only dexamethasone as its active ingredient; but that dexamethasone may be present as dexamethasone base, as dexamethasone phosphate, dexamethasone sodium phosphate, as dexamethasone acetate, as dexamethasone palmitate etc.

• "contains dexamethasone phosphate only" means that a product can contain either dexamethasone phosphate or dexamethasone sodium phosphate (which is a modification of dexamethasone phosphate) as its active ingredient; but it will not contain dexamethasone acetate or dexamethasone palmitate etc.

• "contains dexamethasone phosphate precisely" means that a product will contain exclusively dexamethasone phosphate; dexamethasone sodium phosphate will not be present

See also the subsection below "Using the ingredient roles" which provides a diagram further describing the use of role chaining with the active ingredient role and that there is no role chaining for the precise active ingredient role.

A medicinal product clinical drug concept has one or more substances that have the role of being the substance against which the strength quantity(s) of the product(s) are measured. There will be a basis of strength substance stated for each active ingredient substance present in a multi-ingredient clinical drug product.

Examples:

• azithromycin - in an oral suspension containing azithromycin hemiethanolate, where the strength is 100 mg per 5 mL of azithromycin

• haloperidol in a solution for injection containing haloperidol decanoate, where the strength is 250 mg per 5 mL of haloperidol

• esomeprazole - in a prolonged release tablet containing esomeprazole magnesium, where the strength is 20 mg per tablet of esomeprazole

• oxybutynin chloride – in an oral tablet containing oxybutynin chloride, where the strength is 5 mg per tablet of oxybutynin chloride

Almost always, the basis of strength substance is either the active ingredient substance or the precise active ingredient substance; very occasionally products are licensed using a "reference" basis of strength substance (e.g. a product containing diclofenac diethylammonium as its precise active ingredient substance having its strength expressed in terms of diclofenac sodium).

The Medicinal Product and Medicinal Product Form use the active ingredient attribute, which will have a role chain attached to it, so that it can use the Substance hierarchy as a hierarchy through the "is modification" relationship. This allows the classifier to make the appropriate relationships between MPs, MPFs and CDs based on their active ingredient substances. The role chain is a characteristic that is not inherited, so the precise active ingredient attribute does not inherit this characteristic. The Clinical Drug uses the precise active ingredient attribute/relationship which will use the Substance hierarchy as a flat list without role chaining, so that a clinical drug containing a modified substance is not subsumed under a clinical drug containing the unmodified substance, thereby unintentionally adding more recursion to the clinical drug class (for example: so that a morphine (base) precise clinical drug does not subsume a clinical drug containing precisely morphine sulphate).

Ingredient role is a specific attribute in ISO 11615 in IDMP, but no vocabulary/value set was specified in the conceptual standard for the ingredient roles. Examples that have been given include "active", "inactive" and "adjuvant". This supports the regulatory listing of all the substances present in a product, with their basic role (therapeutic or otherwise).

The explicit use of ingredient roles in the medicinal product model is compatible with the IDMP conceptual model; however, the relationship of ingredient role to substance strength is still being elucidated in IDMP. Note that the concept of "basis of strength substance", in the very few cases where it is not actually a substance present in the product, is managed by the use of the Reference Substance class in IDMP. See also .

This Editorial Guide is used for Education Purposes Only. It is used in the Authoring Courses and Certifications. It is based on the January 2026 Editorial Guide.

To correctly interpret "one countable instance of a whole of medicinal product ", it is important that this is seen in the context of the overall description of a medicinal product, which is always presented from the manufacturer as a "packaged medicinal product". Note that description of packaged medicinal products is outside the scope of the international release but may be included within a national extension. The IDMP Medicinal Product model describes this, showing how the Manufactured Item is related to the Packaged Medicinal Product via the Package Item (Container). This is a recursive class that represents both the package as supplied by the manufacturer (and, for example, labelled with the GTIN, the batch number and the expiry), and through a recursive relationship, with any sub-packages inside the outer pack.

By describing the various standard patterns of products with their basic dose forms and intimate containers, consistent representation of strength based on unit of presentation can be maintained.

This Editorial Guide is used for Education Purposes Only. It is used in the Authoring Courses and Certifications. It is based on the January 2026 Editorial Guide.

Examples: various tablets, capsules, cachets, pessaries, suppositories, tampons

The unit of presentation is usually a less granular term than the manufactured dose form, and often corresponds to the basic dose form. Strength is expressed as "per one unit of presentation" and the presentation strength and the concentration are exactly the same.

Example: Bottle of 56 simvastatin 40mg oral tablets

This Editorial Guide is used for Education Purposes Only. It is used in the Authoring Courses and Certifications. It is based on the January 2026 Editorial Guide.

Examples: parenteral solutions, unit dose nebuliser solutions

The unit of presentation usually either uses the same word (even though it is a different concept) as the (package item) container, or the (package item) container is a more granular concept and the unit of presentation uses a less granular term. Presentation strength is expressed as "per the amount of liquid bounded by the unit of presentation" but concentration strength is per mL (and therefore is often different).

Example: A pack of 10 ampoules each containing 20mL of metoclopramide hydrochloride for solution for injection