An injectable preparation often contains an excess volume above that stated on the label. This guarantees that sufficient material can be withdrawn to deliver the volume given on the label.
Factors affecting the excess amount:
(1) amount of fluid in the vial (20-24% for a 1 mL vial vs 2-3% for >= 50 mL)
(2) viscosity of the fluid (20% vs 24% for a 1 mL vial; 2% vs 3% for >= 50 mL)
|
Size on Label |
Mobile (Low Viscosity) |
High Viscosity |
|
0.5 mL |
0.10 mL |
0.12 mL |
|
1.0 mL |
0.10 mL |
0.15 mL |
|
2.0 mL |
0.15 mL |
0.25 mL |
|
5.0 mL |
0.30 mL |
0.50 mL |
|
10.0 mL |
0.50 mL |
0.70 mL |
|
20.0 mL |
0.60 mL |
0.90 mL |
|
30.0 mL |
0.80 mL |
1.20 mL |
|
>= 50 mL |
2% (1.0 mL for 50 mL) |
3% (1.5 mL for 50 mL) |
If this data is analyzed in JMP, for a low viscosity fluid:
If <= 1.0 mL, extra volume is 0.1 mL.
If >= 50 mL, extra volume is 2%.
For 1.0 to 10 mL, the extra volume approximately =
= (-0.0011 * ((labeled volume in mL)^2)) + (0.05677 * (labeled volume in mL)) + 0.042956
For 10 to 50 mL, the extra volume approximately =
= (-0.000068 * ((labeled volume in mL)^2)) + (0.017046 * (labeled volume in mL)) + 0.322727
For a high viscosity fluid:
If <= 0.5 mL, extra volume is 0.12 mL.
If >= 50 mL, extra volume is 3%.
For 1.0 to 10 mL, the extra volume approximately =
= (-0.004682 * ((labeled volume in mL)^2)) + (0.111649 * (labeled volume in mL)) + 0.052877
For 10 to 50 mL, the extra volume approximately =
= (-0.000182 * ((labeled volume in mL)^2)) + (0.03145 * (labeled volume in mL)) + 0.38727
Limitations:
• The drug company may include more or less than the recommended volume.
Specialty: Pharmacology, clinical
