This is the Continuous Integration Build of FHIR (will be incorrect/inconsistent at times). 
See the Directory of published versions
Compounded Preparation - TPN Solution  - includes a reference to a substance in the ingredient element (id = "med0318")
<?xml version="1.0" encoding="UTF-8"?>
<Medication xmlns="http://hl7.org/fhir">
  <id value="med0318"/> 
  <doseForm> 
    <coding> 
      <system value="http://snomed.info/sct"/> 
      <code value="385221006"/> 
      <display value="Conventional release emulsion for injection (dose form)"/> 
    </coding> 
  </doseForm> 
  <ingredient> 
    <item> 
      <concept> 
        
        <coding> 
          <system value="http://hl7.org/fhir/sid/ndc"/> 
          <code value="0338-1134-03"/> 
          <display value="CLINIMIX, 1000 mL in 1 BAG (0338-1134-03) (package)"/> 
        </coding> 
        <text value="Clinimix 4.25/10 sulfite-free (4.25% Amino Acid in 10% Dextrose) Injection, 1000ml"/> 
      </concept> 
    </item> 
  </ingredient> 
  <ingredient> 
    <item> 
      <concept> 
        <coding> 
          <system value="http://hl7.org/fhir/sid/ndc"/> 
          <code value="0409-5779-01"/> 
          <display value="TPN Electrolytes, 25 VIAL, SINGLE-DOSE in 1 CARTON (0409-5779-01) > 20 mL in
           1 VIAL, SINGLE-DOSE (0409-5779-11) (package)"/> 
        </coding> 
        <text value="TPN Electrolytes SODIUM CHLORIDE, CALCIUM CHLORIDE, POTASSIUM CHLORIDE, MAGNESIUM
         CHLORIDE, and SODIUM ACETATE ANHYDROUS | INJECTION, SOLUTION, CONCENTRATE | 321
         mg/20mL, 331 mg/20mL, 1491 mg/20mL, 508 mg/20mL, 2420 mg/20mL"/> 
      </concept> 
    </item> 
  </ingredient> 
  <ingredient> 
    <item> 
      <concept> 
        <coding> 
          <system value="http://hl7.org/fhir/sid/ndc"/> 
          <code value="0338-0519-02"/> 
          <display value="Intralipid, 250 mL in 1 BAG (0338-0519-02) (package)"/> 
        </coding> 
        <text value="Intralipid 20% IV Fat Emulsion"/> 
      </concept> 
    </item> 
  </ingredient> 
  <batch> 
    <lotNumber value="123455"/> 
    <expirationDate value="2016-07-09"/> 
  </batch> 
</Medication> 
 
Usage note: every effort has been made to ensure that the 
examples are correct and useful, but they are not a normative part 
of the specification.