77 / 86
efficacy in the treatment of glabellar frown lines for
up to 4 months.
52
In the 2004 consensus panel, 73%
of panelists stored onabotulinumtoxinA for more
than 4 hours.
22
Lizarralde and colleagues studied 30 patients
injected for external canthus dynamic lines with
onabotulinumtoxinA reconstituted 1 week before its
use. They found clinical results similar to those with
freshly reconstituted toxin.
53
Another study
54
demonstrated that onabotulinumtoxinA used after
2 weeks of refrigeration had no changes in time
of onset or efficacy in the treatment of lateral or-
bital rhytides, and a recent experimental trial in
mice did not find loss of efficacy in onabotulinum-
toxinA vials reconstituted for up to 6 weeks before
use.
47
A study with abobotulinumtoxinA
55
reconstituted 2
weeks before injection in 105 patients found no
difference in safety or efficacy. A consensus panel in
2010
32
found that reconstituted abobotulinumtox-
inA can be used within 2 to 3 weeks without adverse
effects.
Fresh or Frozen
In animal models, Gartlan and Hoffmann
27
and
Jabor and colleagues
28
found loss of efficacy if the
onabotulinumtoxinA was frozen for longer than 2
weeks. Greene
29
‘‘argued that in vitro experiments
may not reflect clinical practice.’’ His opinion that
the frozen toxin remained effective for several weeks
was similar to clinical study results
30,31
that found
no loss of activity or additional side effects for up to
8 weeks.
Parsa and colleagues
4
compared reconstituted
onabotulinumtoxinA frozen for up to 6 months with
onabotulinumtoxinA not frozen and used within
4 hours after reconstitution in 118 sites in 80
patients and concluded that reconstituted
onabotulinumtoxinA may be frozen, thawed,
and injected without losing its potency for up to
6 months. Kane found that these conclusions
were consistent with anecdotal reports from many
injectors.
56
The ultrastructural alterations of the muscle and
nerve after the injection of fresh versus stored
onabotulinumtoxinA were evaluated using electron
microscopy.
57
Fifteen rabbits were injected with
toxin freshly reconstituted or stored for 2 weeks
under refrigeration and had muscles and motor
nerves harvested at 5 days and 12 weeks. No dif-
ferences were found at the 5-day evaluation. At 12
weeks, the group that used stored toxin showed less-
severe atrophic changes in the muscle, whereas no
differences were encountered on nerve evaluation. In
the same experimental trial in mice cited above,
Shome and colleagues
47
did not find loss of efficacy
in onabotulinumtoxinA vials reconstituted and kept
refrigerated for up to 6 weeks before use.
Yang and colleagues,
58
in a prospective, double-
blind, randomized controlled trial with 40 subjects
treated for horizontal forehead rhytides, found no
difference in potency or duration of efficacy of
abobotulinumtoxinA after 2 weeks of refrigeration
or freezing from that of freshly reconstituted
abobotulinumtoxinA.
Sterility
Because storing and reusing reconstituted toxin for a
period of weeks has become a frequent practice,
sterility assessment is an important issue that some
authors have addressed.
Alam and colleagues
59
evaluated 127 vials of
onabotulinumtoxinA reconstituted using preserva-
tive-containing saline, stored, and reused, simulating
the routine storage and extraction methods per-
formed in clinical practice. Each vial underwent an
average of 4.5 access procedures during a period of
up to 7 weeks, and contamination was not evidenced
in sterility analysis.
Menon
60
analyzed 11 consecutive bottles of
abobotulinumtoxinA left for 4 hours at room
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