Volumex

Volumex Manufacturers

• Iso-tex Diagnostics, Inc.
  

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  Volumex | Iso-tex Diagnostics, Inc.

  

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  Volumex (Iodinated I 131 Albumin Injection) is administered intravenously.

  Parenteral drug products should be inspected visually for particulate matter and

  abnormal coloration prior to administration whenever solution and container per-

  mit.
      Volumex (Iodinated I 131 Albumin Injection) may be colorless to very pale

  yellow. Solutions with excessive coloration should not be used.

      When a procedure such as a blood volume or a circulation time determination

  is to be repeated, the total dosage administered in any one week should not

  exceed 200 microcuries.

      To minimize the uptake of radioactive iodine by the thyroid, prior administration

  of Lugol’s Solution (Strong Iodine Solution USP) may be used. Ten drops of

  Lugol’s Solution three times daily, beginning at least 24 hours before administra-

  tion of Volumex and continuing for one or two weeks thereafter, is a suitable

  dose.

     Complete assay data for each single unit dose are provided on the container.

  Note: The expiration date given on the container pertains to the biologic

  properties of the material and not to the radioactivity level. It is important to make

  certain that the radioactivity in the dose at the time of administration is sufficient

  for the intended use.

      The patient dose should be measured by a suitable radioactivity calibration

  system immediately prior to administration.

     Note: A shielded syringe may be used for withdrawing and injecting the

  iodinated I 131 albumin.

  Total Blood and Plasma Volumes

  Dosage may range from 5 to 50 microcuries.

  Blood Volume Determination

  A. Reference Solution

  Reference solution is provided with each single unit dose of Volumex. Determine

  the radioactivity concentration (net cpm/mL) of the reference solution. Care must

  be taken to assure that the reference solution and the blood samples (Step B3)

  are assayed using the same geometric configuration.

  
  B. Administration of Dose

  1. After withdrawing a background blood sample as described below, insert an

      intravenous (IV) line into a large vein in patient’s arm. Inject the entire

      Volumex dose (one milliliter) through the IV line for immediate delivery.

      Measure the residual radioactivity in the syringe and needle.

  2. Destroy syringe after injecting. Do not attempt to resterilize. CAUTION: The

      syringe should be disposed of in accordance with the US Nuclear Regulatory

      Commission or Agreement State regulations pertaining to the disposal of ra-

      dioactive waste.

  3. At 12, 18, 24, 30 and 36 minutes after injecting the dose, withdraw blood

      samples from the patient with a sterile syringe or evacuated

      sample tube containing anti-coagulant.

  
  C. Calculation of Blood Volume

  1. Take a known aliquot from each blood sample and determine radioconcentration

  in net cpm/mL.

  2. Plot the 12, 18, 24, 30 and 36 minute sample counts (net cpm/mL) on semilog-

      graph paper using the average count value of each sample and determine the

      radioconcentration at injection time (zero time) by drawing a straight line through

      the 12, 18, 24, 30 and 36 minute points to zero time. The x ordinate of the

      graph is the sample withdrawal time and the logarithmic y ordinate is

      radioconcentration in net cpm/mL.

  3. Calculate patient’s blood volume (in mL) using the following formula:

  Net cpm/mL reference solution                                  blood
  Net cpm/mL patient’s blood sample         x    DF  =    volume
                                                                                   (in mL)

  Sample Blood Volume Calculations

  Volume of Blood sample aliquot                                           =  1.0 mL

  Volume of Reference Solution aliquot                                   =  1.0 mL

  Net counts at zero time                                                    =  48,100

  Net counts obtained from reference solution aliquot               =  52, 430

  If, for example, DF, dilution factor of the reference solution  =  4000

  Using the above formula gives = 52,430   x 4000 = 4360 mL

                                                      48,100

  Serial Blood Volume Determinations

  Iodinated I 131 Albumin Injection is administered in sufficiently low dosage to permit

  repetitions as often as required by clinical circumstances. It must be remembered

  that it is always necessary to correct for background radioactivity remaining in the

  blood from former determinations. Therefore, for each determination after the first

  one, a background blood sample must be taken just before the iodinated I 131

  albumin is injected.

  Background Blood Sample

  1. Withdraw background blood sample from large vein in patient’s sampling arm

      with a sterile syringe or evacuated sampling tube containing anti-coagulant.

  2. Leaving needle in patient’s vein, detach syringe containing blood sample.

  3. Attached syringe containing the dose of Volumex to the indwelling IV line

     and administer (see instructions under Blood Volume Determination,

     Administration of Dose).

  4. Determine radioconcentration in net cpm/mL of aliquots taken from back-

     ground and postinjection blood samples, and from the reference solution.

    The radioconcentration (net cpm/mL) per aliquot of the background blood

    sample must be subtracted from the radioconcentration per aliquot of the blood

    sample obtained after the injection of iodinated I 131 albumin. The formula

    for calculating each blood volume determination after the first one thus becomes:

        Net cpm/mL reference solution blood                   x     DF     =    blood

   Net cpm/mL                           Net cpm/mL                                      volume

  postinjection        minus          background                                     (in mL)

  blood sample                          blood sample

  Plasma Volume Determination

  The procedure is essentially the same as that for blood volume determination,

  except that the blood sample drawn from the patient is centrifuged, the red blood

  cells are removed, and net cpm/mL of the plasma is determined. The formula for

  calculation of plasma volume, therefore is:

  Net cpm/mL reference solution          x DF       =           plasma

  Net cpm/mL patient’s plasma sample                             volume

                                                                               (in mL)

  Protein Turnover Studies

  Dosages used have ranged from 10 to 150 microcuries. After injection, a period

  of seven days should be allowed before determinations are made to permit the

  elimination of any degraded protein in the dose.

  Radiation Dosimetry

  The estimated absorbed radiation doses to an average patient (70 kg) from an

  intravenous injection of 50 microcuries of Iodinated I 131 Albumin Injection USP

  are shown in Table 4.

  For doses of 10, 25, 75, 150, 500 and 750 microcuries, the estimated absorbed

  doses are 0.2, 0.5, 1.5, 3, 10 and 15 times the number of rads given, respectively.

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