How is amoxicillin typically dissolved in water?

Standard Preparation for Oral Use

Amoxicillin powder for oral suspension is typically dissolved by adding the specified volume of water—often distilled or purified—to the provided bottle containing the dry powder. Shake vigorously for at least 2 minutes until fully dissolved and uniform. Common ratios are 60 mL or 120 mL water for pediatric bottles (e.g., 125 mg/5 mL or 250 mg/5 mL strengths). Once mixed, store in the refrigerator and discard after 14 days.[1][2]

Steps for Pharmacy or Home Reconstitution

1. Check the label for exact water volume (e.g., "Add 68 mL water to yield 100 mL suspension").
   
2. Use cool water (room temperature or cooler) to minimize foaming.
   
3. Add water in stages: half first, shake, then the rest, and shake again.
   
4. Verify no undissolved particles remain; it should form a smooth, off-white suspension.[3]
   
   

For Injectable Forms (IV/IM)

Amoxicillin sodium powder for injection dissolves readily in sterile water for injection or 0.9% sodium chloride. Add diluent slowly (e.g., 10 mL for a 1 g vial), swirl gently—do not shake—to avoid bubbles. It dissolves in under 5 minutes at room temperature. Further dilute for IV infusion in 50-100 mL compatible fluid.[4][5]

Solubility Factors and Tips

Pure amoxicillin trihydrate has low water solubility (~4 mg/mL at 37°C), but formulated powders include excipients for faster dissolution (up to 50 mg/mL in suspensions). Heat speeds solubility but risks degradation—avoid temperatures above 40°C. pH 4-6 optimizes stability post-dissolution.[6]

What If It Doesn't Dissolve Fully?

Clumps may form if water is too cold or added too quickly. Let stand 5 minutes, then shake. If gritty, it's likely improper mixing—discard and remix a new batch. Over-dilution weakens potency.[2][3]

Stability After Dissolution

Refrigerated oral suspensions last 7-14 days; frozen ones up to 3 months (thaw once in fridge). IV solutions stable 8 hours at room temp or 48 hours refrigerated. Discard if color changes or odor develops.[1][5]

[1]: FDA Label: Amoxicillin for Oral Suspension (e.g., Teva)
[2]: USP Monograph: Amoxicillin Powder for Oral Suspension
[3]: ASHP Guidelines: Reconstitution of Oral Antibiotics
[4]: Summary of Product Characteristics: Amoxicillin 1g IV (EMA)
[5]: Lexicomp: Amoxicillin Stability Data
[6]: PubChem: Amoxicillin Solubility