2. Experimental
2.1. Apparatus
All fluorescence measurements were done on a
Shimadzu RF-5301 PC spectrofluorophotometer
equipped with a 150 W Xenon lamp, using 1.00
cm quartz cells. Experimental parameters were:
slit width: 5.0 nm, lexc28793 nm, lem3629
2 nm.
Absorbance measurements were done on a
Beckman DU 640 spectrophotometer using 1.00
cm quartz cells.
2.2. Reagents
A stock solution of analytical grade diclofenac
(400 mg l1) was prepared by dissolving 20 mg of
diclofenac with distilled water into a 50.00 ml
volumetric flask, and then diluting with distilled
water (1:10). This latter stock solution was finally
diluted with HCl 0.01 N before the fluorescence
measurements (see below).
2.2.1. Pharmaceutical preparations
Tablets and ointments were obtained from the
following laboratories: Beta (Oxagelsic), Bristol-
Meyer-Squibb (Vesalion), Novartis (Voltaren and
Voltaren Emulgel), Merck (Damixa), and Bago´
(Dioxaflex), and processed as described below.
2.3. Calibration cur6e
Solutions for the calibration curve were prepared
by suitable dilution of the stock solution
with HCl 0.01 N in a 50.00 ml volumetric flask.
The concentration range was 0.2–5.0 mg l1. The
fluorescence intensity was measured at (lem362