Table 2.
Determination of Br and Ti in Combigan® eye drops by the proposed ratio difference method and application of standard addition technique.
| Product in Combigan® eye dropa | Standard addition |
Recovery (mean±SD, %) |
||||
|---|---|---|---|---|---|---|
| Taken (μg/mL) | Added (μg/mL) | Found (μg/mL) | Recovery (%) | Proposed method | Standard addition | |
| Br | 10.00 | 5.00 | 4.93 | 98.60 | 101.08±0.44 | 100.10±1.41 |
| 10.00 | 10.14 | 101.40 | ||||
| 20.00 | 20.06 | 100.30 | ||||
| Ti | 25.00 | 20.00 | 20.15 | 100.75 | 100.66±0.52 | 100.42±0.68 |
| 25.00 | 24.91 | 99.64 | ||||
| 30.00 | 30.26 | 100.87 | ||||
a
Combigan® eye drops, batch no. E62201 labeled to contain 2 mg/mL of brimonidine tartarate and 5 mg/mL of timolol.