Table 1.
Optimization of BGE composition for the determination of lanreotide and triptorelin via CZE-DAD.
| Lanreotide, n =3 | Triptorelin, n =3 | ||||||
|---|---|---|---|---|---|---|---|
| BGE | pH | RSDtm (%) | RSDarea (%) | N | RSDtm (%) | RSDarea (%) | N |
| 50 mmol/L HFo | 2.54 | 16.9 | 22.1 | 44,312 | 17.8 | 21.6 | 39,420 |
| 100 mmol/L HFo | 2.38 | 1.7 | 2.8 | 75,129 | 1.6 | 2.6 | 74,069 |
| 250 mmol/L HFo | 2.18 | 0.9 | 0.9 | 109,590 | 0.9 | 0.4 | 106,053 |
| 500 mmol/L HFo | 2.03 | 0.4 | 1.8 | 94,823 | 0.3 | 1.6 | 92,521 |
| 1000 mmol/L HFo | 1.88 | 4.9 | 4.5 | 95,303 | 5.1 | 7.5 | 97,016 |
| 100 mmol/L HFo + 100 mmol/L HAc | 2.63 | 0.5 | 2.1 | 38,430 | 0.5 | 2.4 | 31,340 |
| 250 mmol/L HFo + 250 mmol/L HAc | 2.43 | 1.1 | 4.2 | 71,222 | 1.0 | 2.2 | 63,824 |
[i] BGE, background electrolyte; CZE-DAD, capillary zone electrophoresis with diode-array detection; HAc, acetic acid; HFo, formic acid; RSD, relative standard deviation. RSDarea is the RSD of the peak area, RSDtm is the RSD of the migration time, and N is the separation efficiency and it was calculated using the equation N = 5.545 × (tm/w1/2)2 where tm is the migration time and w1/2 is the peak width at half height. The concentration of lanreotide and triptorelin standards was 10 μg/mL.
Table 2.
CZE-DAD operation and calibration parameters for lanreotide and triptorelin analysis in an aqueous matrix.
| Parameter | Lanreotide | Triptorelin |
|---|---|---|
| tm (min) | 3.95 | 4.35 |
| RSDtm (%), n = 4 | 0.21 | 0.23 |
| RSDarea (%), n = 4 | 1.64 | 1.64 |
| Regression equation | y = 13.427x − 6.0741 | y = 13.537x − 8.5831 |
| r2 | 0.996 | 0.991 |
| Linear range (μg/mL) | 2–16 | 2–16 |
| LOD (μg/mL) | 0.5 | 0.5 |
| LOQ (μg/mL) | 2 | 2 |
| N | 34,606 | 29,079 |
Table 3.
Precision and accuracy of the CZE-DAD method for lanreotide and triptorelin quantification.
| Lanreotide | Triptorelin | ||||||
|---|---|---|---|---|---|---|---|
| Nominal (µg/mL) | Found (µg/mL) | RSD (%) | RE (%) | Found (µg/mL) | RSD (%) | RE (%) | |
| Intraday, n = 4 | 2 | 2.07 | 1.6 | 3.4 | 2.12 | 1.6 | 6.2 |
| 4 | 3.96 | 2.8 | −1.0 | 3.71 | 2.6 | −7.3 | |
| 8 | 7.82 | 3.5 | −2.3 | 8.13 | 7.1 | 1.7 | |
| 12 | 12.25 | 3.1 | 2.1 | 12.18 | 4.0 | 1.5 | |
| 16 | 15.90 | 3.6 | −0.6 | 15.86 | 5.5 | −0.9 | |
| Interday, n = 12 | 2 | 2.19 | 6.7 | 9.7 | 2.27 | 4.1 | 13.6 |
| 4 | 3.94 | 6.2 | −1.4 | 3.88 | 4.2 | −2.9 | |
| 8 | 7.69 | 4.5 | −3.9 | 7.53 | 3.7 | −5.9 | |
| 12 | 12.12 | 4.6 | 1.0 | 12.34 | 3.7 | 2.9 | |
| 16 | 16.06 | 2.7 | 0.4 | 15.97 | 2.8 | −0.2 | |
Table 4.
Short-term stability assessment of lanreotide and triptorelin standards in aqueous solutions.
| Storage conditions (°C) | Sample/fresh solution peak area ratio | |
|---|---|---|
| Lanreotide, n = 4 | Triptorelin, n = 4 | |
| 20 | 0.81 ± 0.08 | 0.83 ± 0.12 |
| 4 | 0.87 ± 0.06 | 1.02 ± 0.08 |
| −20 | 0.94 ± 0.10 | 1.05 ± 0.02 |
Figure 1.
Electropherograms illustrating the simultaneous analysis of lanreotide (L) and triptorelin (T) at their LOQ concentration level (2 ug/mL) in the aqueous matrix, comparing wavelengths: (a) 220 nm and (b) 200 nm. LOQ, limit and quantification.
Figure 2.
Electropherogram depicting the analysis of Diphereline® with expected triptorelin content at the concentration level of 5 ug/mL after dilution.
Figure 3.
Greenness and applicability comparison of CE methods developed for lanreotide and triptorelin analysis: CE-MS (Piešťanský et al., 2021), CZE-UV (Stefanik et al., 2024b), and CZE-DAD (present study) using GAPI, AGREE, and BAGI metrics. AGREE, analytical GREEnness; BAGI, Blue Applicability Grade Index; CE-MS, capillary electrophoresis-mass spectrometry; CZE-DAD, capillary zone electrophoresis with diode-array detection; GAPI, Green Analytical Procedure Index.