Brazilian Journal of Analytical Chemistry - BRJAC - Brazilian Journal ...

the standard deviation from 16 blank determinations,
m are the slopes of the analytical curves, MM is the
molar mass of ciprofloxacin and V is the analyte volume
deposited on the substrate (5 µL).
The analytical curves showed linear dynamic ranges
that extended from the ALOQ to at least 415 ng of ciprofloxacin.
The analyte curve equations were Y = 0.41 ng -1
X + 44 for substrates containing Th(NO 3 ) 4 and Y = 1.11
ng -1 X + 59 for substrates containing CdCl 2 . The curves
presented a homoscedastic behavior and their determination
coefficients were close to the unity (R 2 >0.99).
Evaluations of the repeatability were performed using
two different masses of the analyte (83 and 331 ng). The
relative standard deviation of the measured values varied
from 3.2 to 6.6% what can be considered satisfactory
for measurements from solid substrates.
3.5. ap p l I c a t I o n of th e me t h o d
The proposed SSRTP method was applied for the
quantification of ciprofloxacin in one commercial pharmaceutical
formulation. Other two simulated formulations
were also analyzed. These simulated samples
were prepared by mixing a known amount of ciprofloxacin
standard with the pulverized pharmaceutical
formulation of either gatifloxacin or moxifloxacin in
Analyte
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order to get ciprofloxacin/gatifloxacin or ciprofloxacin/
moxifloxacin proportions of either 1/1 or 1/2 w/w. The
recovery values were calculated based on the ciprofloxacin
quantity indicated on the medicine instruction,
which agreed with experimental results found using a
reference HPLC with fluorescence detection 17 . Recovery
tests were made using each one of the heavy atom
salts as phosphorescence enhancer in order to get a
comparison of performance. The tabulated values are
averages of three different determinations performed
in three different days and a Student t-test (at 95%
confidence level) was used to statistically compare the
experimental result with the reference one.
The determination of ciprofloxacin in the pharmaceutical
formulation was successfully achieved with recoveries
of 97.9 ± 4% (using Th(NO 3 ) 4 ) and 103.8 ±
1% (using CdCl 2 ) indicating no interference problems
imposed by the matrix components. For synthetic mixtures,
results in Table IV indicates that the use of Th
(IV) allowed accurate ciprofloxacin determinations in
1/1 and 1/2 w/w ciprofloxacin/gatifloxacin or ciprofloxaxin/moxifloxacin
mixtures. Spectral interferences were
found when larger proportions of moxifloxacin and
gatifloxacin were present as indicated by the percent
recoveries significantly higher than 100%. On the other
taBlE iii. Evaluation o f intErfErEnCEs o f g a t i f l o x aC i n a n d m o x i f l o x aC i n in thE C iP ro f l o x a C i n PhosPhorEsCEnCE u s i n g s y n C h ro n i zE d s C a n n i n g.
Mixture
(molar proportion)
Ciprofloxacin/Gatifloxacin
taBlE iv. rECovEry tEsts u s i n g simulatEd PharmaCEutiCal f o r m u l a t i o n s u s i n g s y n C h ro n o u s s C a n n i n g ssrtP.
Concomitant
florquinolone
Analyte/concomitant
florquinolone
proportion
Analyte recoveries a
Th(NO ) 3 4
CdCl2 Ciprofloxacin Gatifloxacin 1/1 103 ± 8.8% 56.4 ± 4.7%
Ciprofloxacin Gatifloxacin 1/2 97 ± 11% 22 ± 8%
Ciprofloxacin Moxifloxacin 1/1 94.3 ± 3.6% 61 ± 12%
Ciprofloxacin Moxifloxacin 1/2 99 ± 7.4% 36.3 ± 3.8%
a Average of three determinations (n=3).
Th(NO 3 ) 4
I CIP /I (CIP + GAT)
CdCl 2
1/1 0.99 1.86
1/2 0.98 2.49
1/5 3.12 2,49
1/10 4.14 3.31
Ciprofloxacin/Moxifloxacin
I /I CIP (CIP + MOX)
1/1 1.00 1.49
1/2 0.97 2.11
1/5 0.66 2.85
1/10 0.47 2.85
Nava-Júnior and Aucelio
129