Generic Formulation - Azithromycin 250mg oral capsule - includes a reference to a substance in the Ingredient element

{
  "resourceType": "Medication",
  "id": "med0320",
  "text": {
    "status": "generated",
    "div": "<div xmlns=\"http://www.w3.org/1999/xhtml\"><p><b>Generated Narrative: Medication</b><a name=\"med0320\"> </a></p><div style=\"display: inline-block; background-color: #d9e0e7; padding: 6px; margin: 4px; border: 1px solid #8da1b4; border-radius: 5px; line-height: 60%\"><p style=\"margin-bottom: 0px\">Resource Medication &quot;med0320&quot; </p></div><p><b>code</b>: Azithromycin 250mg capsule (product) <span style=\"background: LightGoldenRodYellow; margin: 4px; border: 1px solid khaki\"> (<a href=\"https://browser.ihtsdotools.org/\">SNOMED CT</a>#324252006)</span></p><p><b>doseForm</b>: Tablet dose form (qualifier value) <span style=\"background: LightGoldenRodYellow; margin: 4px; border: 1px solid khaki\"> (<a href=\"https://browser.ihtsdotools.org/\">SNOMED CT</a>#385055001)</span></p><blockquote><p><b>ingredient</b></p><h3>Items</h3><table class=\"grid\"><tr><td>-</td><td><b>Reference</b></td></tr><tr><td>*</td><td><a name=\"sub03\"> </a><blockquote><p/><p><a name=\"sub03\"> </a></p><p><b>instance</b>: false</p><h3>Codes</h3><table class=\"grid\"><tr><td>-</td><td><b>Concept</b></td></tr><tr><td>*</td><td>Azithromycin (substance) <span style=\"background: LightGoldenRodYellow; margin: 4px; border: 1px solid khaki\"> (<a href=\"https://browser.ihtsdotools.org/\">SNOMED CT</a>#387531004)</span></td></tr></table></blockquote></td></tr></table><p><b>strength</b>: 250 mg<span style=\"background: LightGoldenRodYellow\"> (Details: UCUM code mg = 'mg')</span>/1(unit TAB from http://terminology.hl7.org/CodeSystem/v3-orderableDrugForm)<span style=\"background: LightGoldenRodYellow\"> (Details: http://terminology.hl7.org/CodeSystem/v3-orderableDrugForm code TAB = 'Tablet')</span></p></blockquote></div>"
  },
  "contained": [
    {
      "resourceType": "Substance",
      "id": "sub03",
      "instance": false,
      "code": {
        "concept": {
          "coding": [
            {
              "system": "http://snomed.info/sct",
              "code": "387531004",
              "display": "Azithromycin (substance)"
            }
          ]
        }
      }
    }
  ],
  "code": {
    "coding": [
      {
        "system": "http://snomed.info/sct",
        "code": "324252006",
        "display": "Azithromycin 250mg capsule (product)"
      }
    ]
  },
  "doseForm": {
    "coding": [
      {
        "system": "http://snomed.info/sct",
        "code": "385055001",
        "display": "Tablet dose form (qualifier value)"
      }
    ]
  },
  "ingredient": [
    {
      "item": {
        "reference": {
          "reference": "#sub03"
        }
      },
      "strengthRatio": {
        "numerator": {
          "value": 250,
          "system": "http://unitsofmeasure.org",
          "code": "mg"
        },
        "denominator": {
          "value": 1,
          "system": "http://terminology.hl7.org/CodeSystem/v3-orderableDrugForm",
          "code": "TAB"
        }
      }
    }
  ]
}