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Celestone Chronodose

Overview

Field Detail
Drug class Corticosteroid (betamethasone brand)
Route IM
Stock formulation 5.7 mg/1 mL
Reconstituted conc. N/A (Ready to use)
Diluent Nil
Storage Room temperature; protect from light

Note

Celestone Chronodose is a branded formulation of betamethasone. See also Betamethasone.

Preparation

Before you start

Check the expiry date and vial integrity before opening. Label every syringe immediately after drawing up — never leave unlabelled syringes on the tray.

Equipment needed

  • 1 × Celestone Chronodose 5.7 mg/1 mL vial
  • Normal saline (NS) — for IDT dilutions
  • 1 mL syringes × 3
  • 25 G needles

Step 1 — Prepare the SPT solution (5.7 mg/mL — neat)

  1. Draw up 0.5–1 mL of the stock (5.7 mg/mL) into a 1 mL syringe.
  2. Label: "Celestone Chronodose SPT 5.7 mg/mL".

Step 2 — Prepare IDT dilutions

Prepare in this order, using a fresh syringe for each step.

  1. IDT 0.057 mg/mL (1:100):

    • Draw 0.1 mL of stock (5.7 mg/mL) into a 1 mL syringe. Add 0.9 mL NS. Mix. (This is 0.57 mg/mL — 1:10).
    • Draw 0.1 mL of this 0.57 mg/mL into a new 1 mL syringe. Add 0.9 mL NS. Mix. (This is 0.057 mg/mL — 1:100).
    • Label: "Celestone Chronodose IDT 0.057 mg/mL".

  2. IDT 0.38 mg/mL (1:15):

    • Draw 0.2 mL of stock (5.7 mg/mL) into a 1 mL syringe. Add 2.8 mL NS. Mix. (This is 0.38 mg/mL — 1:15).
    • Label: "Celestone Chronodose IDT 0.38 mg/mL".

Unusual dilution

The 1:15 dilution for Step 2 is non-standard. Ensure accuracy when measuring 0.2 mL stock + 2.8 mL NS.

Skin prick test (SPT)

Reagent Concentration
Test solution Neat (5.7 mg/mL)
Positive control Histamine 10 mg/mL
Negative control Normal saline

Interpretation: Wheal ≥3 mm vs negative control = positive.

Intradermal test (IDT)

Dilution series

Step Dilution Concentration Preparation
1 1:100 0.057 mg/mL 0.1 mL of 0.57 mg/mL + 0.9 mL NS
2 1:15 0.38 mg/mL 0.2 mL of 5.7 mg/mL + 2.8 mL NS

Inject: 0.05 mL intradermal. Read at 15–20 minutes.