The solubility of labetalol hydrochloride in water is approximately 20mg per mL. Solutions are most stable at pH 2 - 4. The injection, 5mg per mL, could be administered orally if very small doses are required.
The stability of labetalol hydrochloride in distilled water, simple syrup, apple juice, grape juice and orange juice has been reported.1 Solutions were chemically stable in amber glass and plastic containers for 4 weeks. Parabens can be added to these formulations to prevent microbial growth.
Formula 1
Labetalol 10mg per mL |
| |
| Labetalol hydrochloride tablets 100mg |
10 |
|
| Parabens |
0.1 |
% |
| Suitable vehicle as above to |
100 |
mL |
| |
If necessary adjust the final pH to about 4 with citric acid.
|
| |
|
Expiry/Stability: 30 days. |
| |
|
Storage: Refrigerate. Protect from light (amber containers).
|
| |
Shake well before use
(drug may be bound to insoluble tablet excipients). |
| |
|
|
|
NOTES
- With the range of tablet strengths available, crushing or dispersing the tablet prior
to adminstration is often possible.
- Labetalol 40mg per mL prepared from tablets in a 1:1 mixture of Ora-Sweet and Ora-Plus, or
a 1:1 mixture of Ora-Sweet SF and Ora-Plus or Cherry Syrup was stable for up to 60 days
at 5°C or 25°C, protected from light.2
REFERENCES
- Nahata M.C. Stability of labetalol hydrochloride in distrilled water, simple syrup and
three fruit juices.
DICP Ann Pharmacother 1991; 25: 465-9.
- Allen L.V., Erickson M.A. Stability of labetalol hydrochloride, metoprolol tartrate,
verapamil hydrochloride and spironolactone with hydrochlorothiazide in extemporaneously compounded
oral liquids.
Am J Health-Syst Pharm 1996; 53: 2304-9.
|