Table 3 Radiolabeling standardization of the synthetic peptide LyeTx I-K-HYNIC derivative with ^99mTc

Amount of LyeTx I-K-HYNIC (SnCl₂ ^.2H₂O = 200 μg; pH = 7; Δ = 15 min)

20 μg

 RP (%)

82 ± 1^b

Amount of SnCl₂ ^.2H₂O (LyeTx I-K-HYNIC = 10 μg; pH = 7; Δ = 15 min)

200 μg

250 μg

300 μg

 RP (%)

83 ± 1

87 ± 1

82 ± 3

^99mTcO₂ (%)

9 ± 1^a

8 ± 0^a

14 ± 2^b

^99mTcO₄ ⁻ (%)

8 ± 0^a

5 ± 1^b

4 ± 1^b

pH (LyeTx I-K-HYNIC = 10 μg; SnCl₂ ^.2H₂O = 250 μg; Δ = 15 min)

5

6

7

8

9

 RP (%)

77 ± 2^a

88 ± 2^b

87 ± 1^b

83 ± 0^b

72 ± 3^c

Heating (100 °C) (LyeTx I-K-HYNIC = 10 μg; SnCl₂ ^.2H₂O = 250 μg; pH = 7)

15 min

30 min

Unheated

 RP (%)

87 ± 1^b

81 ± 1^b

57 ± 4^c