Subcutaneous injection: difference between revisions
Diff·revision 5 → 6·18:08, 14 Sep 2024
Difference between revision 5 and revision 6 of Subcutaneous injection. 5 lines changed; the page grew by 836 bytes.
| Revision 5 — 08:29, 2 Sep 2024 MassSpecMarv (talk) add short description 2,092 bytes ±0 | Revision 6 — 18:08, 14 Sep 2024 BUD_Bertram (talk) move a stray full stop inside the reference 2,928 bytes +836 | ||
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| 11 | The route suits peptides for two reasons. Absorption is largely by capillary and lymphatic uptake, which handles large molecules that would be destroyed in the gut; and the depot behaviour of the tissue smooths the concentration profile, which is desirable for a drug intended to act over days.{{r|richter2012}} | 11 | The route suits peptides for two reasons. Absorption is largely by capillary and lymphatic uptake, which handles large molecules that would be destroyed in the gut; and the depot behaviour of the tissue smooths the concentration profile, which is desirable for a drug intended to act over days.{{r|richter2012}} |
| 12 | 12 | ||
| + | 13 | Absorption rate varies with site, with depth, with local blood flow and with the physicochemical properties of the injected material. For an [[Albumin binding half-life extension|albumin-binding]] peptide with a half-life of days these variations are negligible against the dosing interval; for a short-acting preparation they are not.{{r|richter2012}} | |
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| 13 | == Anatomy and technique == | 15 | == Anatomy and technique == |
| 14 | The subcutaneous layer lies between the dermis and the muscle fascia, and its thickness varies greatly by site and by individual — from a few millimetres to several centimetres. Needle length is chosen so that the tip reaches this layer without passing into muscle, which is why short needles of 4–8 mm are used in current practice.{{r|ada2024}} | 16 | The subcutaneous layer lies between the dermis and the muscle fascia, and its thickness varies greatly by site and by individual — from a few millimetres to several centimetres. Needle length is chosen so that the tip reaches this layer without passing into muscle, which is why short needles of 4–8 mm are used in current practice.{{r|ada2024}} |
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| 16 | Injection into muscle rather than fat accelerates absorption, sometimes substantially. For insulin this is a well-documented cause of unexpected hypoglycaemia; for long-acting peptides the consequence is smaller because the absorption step is not rate-limiting. | 18 | Injection into muscle rather than fat accelerates absorption, sometimes substantially. For insulin this is a well-documented cause of unexpected hypoglycaemia; for long-acting peptides the consequence is smaller because the absorption step is not rate-limiting. |
| 17 | 19 | ||
| + | 20 | Volume is limited by the compliance of the tissue. More than about 1.5 mL at one site produces discomfort and a visible bleb, and larger volumes are split. Peptide doses in this field are usually well under that, since a few milligrams of peptide occupy a very small volume at ordinary reconstitution concentrations.{{r|richter2012,usp1503}} | |
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| 18 | == References == | 22 | == References == |
| 19 | {{reflist}} | 23 | {{reflist}} |
| 20 | <ref name="ada2024">American Diabetes Association. "Facilitating positive health behaviors and well-being to improve health outcomes: Standards of Care in Diabetes." ''Diabetes Care'' 47(Suppl 1) (2024).</ref> | 24 | <ref name="ada2024">American Diabetes Association. "Facilitating positive health behaviors and well-being to improve health outcomes: Standards of Care in Diabetes." ''Diabetes Care'' 47(Suppl 1) (2024).</ref> |
| 21 | <ref name="richter2012">Richter WF, Bhansali SG, Morris ME. "Mechanistic determinants of biotherapeutics absorption following SC administration." ''The AAPS Journal'' 14(3):559–570 (2012). DOI:10.1208/s12248-012-9367-0. PMID 22619043.</ref> | 25 | <ref name="richter2012">Richter WF, Bhansali SG, Morris ME. "Mechanistic determinants of biotherapeutics absorption following SC administration." ''The AAPS Journal'' 14(3):559–570 (2012). DOI:10.1208/s12248-012-9367-0. PMID 22619043.</ref> |
| + | 26 | <ref name="usp1503">United States Pharmacopeia, General Chapter <1503>, ''Quality Attributes of Synthetic Peptide Drug Substances''.</ref> | |
| 22 | 27 | ||
| 23 | {{DEFAULTSORT:Subcutaneous injection}} | 28 | {{DEFAULTSORT:Subcutaneous injection}} |