SODIUM ACETATE ([1-11C])
INJECTION
detector operating in the range of 190 to 290
nm in series.
Mobile phase: 95.5 % 400 mM K2HPO4 and
of 0.5% acetonitrile (v:v).
Column: 4.6-mm × 150-mm column that
contains packing L21 (spherical styrene divinyl
copolymer) or similar column.
Flow rate: ~ 0.75 mL per min.
Injection volume: 20 μL
System suitability (UV Detector)
Sample: Standard solution
Suitability requirements
Column efficiency: NLT 2,000 theoretical
plates
Tailing factor: NMT 2.0
% RSD: 2%
Suitability (Gamma-ray Detector)
Samples: Use the injection diluted in
mobile phase
Suitability requirements
Column efficiency: NLT 2,000 theoretical
plates
Tailing factor: NMT 2.0
% RSD: 5%
Analysis: Prepare a mixture of the Test solution
and the Standard solution as described in
radiochemical identification, inject into the
chromatograph, record the chromatograms, and
measure the areas for the radioactive peaks. The
ratio and injected volume may be adjusted to
obtain suitable detection system sensitivity.
Determine the radiochemical purity by dividing
the area of the [11C]acetate radioactivity peak
(see test for radiochemical identity) by sum of all
radioactivity peak areas.
Acceptance criteria: The radiochemical purity is
NLT 90%.
CH3[11C] O2 Na
Sodium [1-11C ] Acetate
DEFINITION
Sodium [1-11C ] Acetate injection is a sterile
solution, suitable for intravenous administration, of
Sodium Acetate in which a portion of the carbonyl
molecules are labeled with radioactive 11C (see
Radiopharmaceuticals for Positron Emission
Tomography – Compounding <823>). It contains
NLT 90% and NMT 110% of the labeled amount of
11
C expressed in MBq (or mCi) at the time indicated
in the labeling. It may contain suitable buffers.
IDENTIFICATION
 RADIONUCLIDIC IDENTITY
Analysis: The T½ of 20.4 minutes is determined
using a suitable detector system. The data
should be recorded over an appropriate time and
used to calculate the half-life.
Acceptance criteria: The T½ is NLT 19.9 min
and NMT 20.9.
 RADIOCHEMICAL IDENTIFICATION
Analysis: Obtain a chromatogram as
described in Radiochemical purity. The
retention time of the major peak in the
chromatogram of the Test solution corresponds
to that in the chromatogram of the Standard
solution, as obtained in the test for
Radiochemical purity.
Acceptance criteria: The retention times of the
sodium acetate and [11C]acetate fall within ± 10%
of each other. [NOTE—the typical retention time
for [11C]acetate is about 2.9 min and for sodium
acetate about 2.8 min.]
 RADIONUCLIDIC PURITY
Analysis: Count an appropriate aliquot of
injection for a period of time sufficient to obtain a
gamma spectrum. The resultant gamma
spectrum should be analyzed for the presence of
identifiable photopeaks which are not
characteristic of 11C emissions.
Acceptance criteria: Carbon-11: minimum 99.5
percent of the total radioactivity of the gamma
emissions should correspond to the 0.511 MeV
(annihilation peak), 1.022 MeV (sum peak), or
Compton scatter peaks of 11C, with no individual
impurity peaks present above 0.5 % at time of
injection determined using a suitable gamma-ray
spectrometer (see Selection of a Counting
Assembly under Radioactivity <821>.
ASSAY
 RADIOACTIVITY <821>
Analysis: Using a suitable calibrated system
(see Radioactivity <821>), determine the
radioactivity of the Sample solution, in MBq (or
mCi) per mL, of the Injection.
PURITIES
 RADIOCHEMICAL PURITY
Standard solution: 20 mg/mL of sodium
acetate RS in mobile phase.
Sample solution: Use the Injection diluted in
mobile phase.
Liquid Chromatographic system
Mode: HPLC
Detectors: Flow through radioactivity
detector, and a variable wavelength UV
 CHEMICAL PURITY
The methods and limits described in this section
relate to potential impurities associated with
commonly used methods of synthesis. If other
1
methods of synthesis result in impurities with
toxic potential, they must be determined to be
within acceptable limits, and conformance with
these limits demonstrated by the use of one or
more validated limit tests.
Sodium acetate:
If the particular production method is incapable of
producing an amount of acetate in excess of 2.0
% (w/100 mL) then measurement of the acetate
quantity is not required.
Standard solution: sodium acetate RS 20 mg/V
in mobile phase, V being the maximum
recommended dose in milliters.
Sample solution: Use the Injection diluted in
mobile phase.
Analysis: Obtain chromatograms as directed in
the test for Radiochemical purity. On the UV
chromatogram for the Standard solution,
measure the peak area for the peak associated
with sodium acetate RS. Measure the peak area
for the corresponding peak in the UV
chromatogram for the Sample solution.
Acceptance Criteria:
Not more than the area of the corresponding
peak in the chromatogram obtained with the
reference solution (20 mg per V)
Residual Solvents are limited according to
General Chapter <467> Residual Solvents
ADDITIONAL REQUIREMENTS
 PACKAGING AND STORAGE: Preserve in singledose or multiple-dose containers that are
adequately shielded.
 USP REFERENCE STANDARDS <11>:
USP Endotoxin RS
USP sodium acetate RS
SPECIFIC TESTS
 BACTERIAL ENDOTOXINS <85>: The final
product cannot contain more than 175 USP
Endotoxin Units in the entire batch volume of
sodium [11C]acetate Injection.
 PH
Sample solution: Use the Injection.
Analysis: Apply the Sample solution to pH
paper strips that have a resolution of at least 1
pH unit. Observe and record the results
immediately after the color changes are
complete.
Acceptance criteria: 4.0 – 9.0
 FILTER INTEGRITY: Use the bubble point
measurement to test the membrane filter
integrity. The acceptance criteria for the bubble
point should be in accordance with the filter
manufacturer’s specification(s).
 OTHER REQUIREMENTS:
The final product meets the requirements
under Injections <1>, except that the Injection
may be distributed or dispensed prior to
completion of the test for Sterility <7> and it is
not subject to the recommendation in Volume
in Container (see Radiopharmaceuticals for
Positron Tomography-Compounding <823>).
The Sterility test should be started within 30
hours of end of synthesis.
2