Effects of topical suprofen and flurbiprofen on the miosis produced by anterior chamber irrigation with cholinergic agonists

Effect of Flurbiprofen on Acetylcholine-Induced Pupillary Contraction

Preoperative treatment with topical nonsteroidal anti-inflammatory agents such as flurbiprofen (Ocufen) is used to maintain pupil dilatation during cataract surgery. Flurbiprofen maintains pupil dilatation by inhibiting release of prostaglandins and other modulators of surgical miosis. Some reports suggest that these agents may reduce the miotic effect of intra-operative acetylcholine (Miochol). It is hard to explain this effect unless there is a pharmacological interaction between the two drugs. This study aimed to investigate the possibility of a direct interference by flurbiprofen with the action of acetylcholine on the pupil sphincter.

Iris tissue of seven cadaver eyes were isolated and maintained in an organ bath containing Kreb's solution. Pupil contraction force induced by acetylcholine was measured in the presence and absence of flurbiprofen. Acetylcholine produced a mean pupillary contraction force of 52.4 × 10–3 N. When it was added to the organ bath in the presence of flurbiprofen the mean contraction force was 50.6 × 10–3 N (paired t-test P=0.68).

This study does not find any evidence to suggest that flurbiprofen reduces the pupil sphincter contraction that is induced by acetylcholine. It is likely that the apparent reduction in miosis is due to factors other than the mechanism of action of acetylcholine on the sphincter pupillae.

Comparative study of the analgesic efficacy of flurbiprofen and diclofenac in patients following excimer laser photorefractive keratectomy

This randomized, patient-masked, crossover trial compared the analgesic efficacy of flurbiprofen and diclofenac in 16 patients following excimer laser photorefractive keratectomy. Patients were randomly assigned to receive one study medication after surgery on the first eye and the other medication after surgery on the second eye (approximately 30 days later). After both surgeries, patients instilled one drop of the assigned medication six times daily for the first 3 days postsurgery and one drop four times daily on postsurgery days 4 through 7. Patients assessed the intensity of postsurgical pain beginning at postsurgery hour 5 and pain relief beginning at postsurgery hour 8 and continued to do so daily thereafter. On the last day (day 7), patients rated the global efficacy of the analgesic treatment. All assessments were performed by patients using descriptor and visual ordinal scales and were recorded in diaries. Patients were queried as to the presence, severity, and duration of any adverse events. Flurbiprofen produced significantly greater reductions in pain intensity than did diclofenac at all evaluations through day 4 and significantly greater relief of pain than did diclofenac at all evaluations through day 3. Significantly more patients treated with flurbiprofen reported being pain free on days 3 and 4 (11 [69%] and 16 [100%], respectively) compared with those treated with diclofenac (3 [19%] and 9 [56%], respectively). Based on patient ratings, flurbiprofen had significantly better global analgesic activity than diclofenac. Both treatments were well tolerated. Mild and transient ocular burning after instillation was the only reported adverse event; it was reported by all patients in both study groups at approximately 50% of study visits.

Swellable microparticles containing Suprofen: evaluation of in vitro release and photochemical behaviour

Suprofen, an anti-inflammatory drug was incorporated in polymer networks based on biocompatible macromolecules, such as alpha,beta-polyasparthydrazide (PAHy) and alpha,beta-poly(N-hydroxyethyl)-DL-aspartamide (PHEA) crosslinked by glutaraldehyde or gamma-rays, respectively. Swelling tests carried out in aqueous media showed that pH value affects the swelling degree of the prepared hydrogels. In vitro release tests were performed in simulated gastrointestinal fluids (pH 1/6.8) using the pH variation method and in phosphate-buffered saline, pH 7.4. Experimental data indicated that Suprofen was released in a sustained way both from PAHy and PHEA microparticles. Further, incorporation of Suprofen in PAHy and PHEA networks provided a significant reduction of the drug photosensitizing activity, as evidenced by in vitro hemolysis tests.

Molecular mechanism of drug photosensitization. 7. Photocleavage of DNA sensitized by suprofen

Ultraviolet-A irradiation of a suprofen (2-[4-2(2-thenoyl) phenyl]propionic acid) (SPF) buffered solution (pH 7.4) in the presence of supercoiled pBR322 DNA leads to single strand breaks with the formation of an open circular form and subsequent linearization of the plasmid. On the basis of agarose gel electrophoresis data of samples irradiated in an air-saturated solution or in an oxygen-modified atmosphere, and the effects of sodium azide, D20, mannitol, copper(II), superoxide dismutase, 2-H-propanol, deferoxamine and surfactants, we suggest a photosensitization mechanism involving singlet oxygen and free radicals. The higher rate of photocleavage in nitrogen compared to that in an air-saturated solution and the results obtained from oxygen consumption measurements support the hypothesis that both the type I and type II photosensitization mechanisms are operative and that oxygen quenches the excited state of the irradiated drug. The photosensitization model applied was in agreement with that previously applied to cell membrane SPF photoinduced damage. Interaction of the drug with DNA, studied through circular dichroism and fluorescence anisotropy, probably occurs through a surface binding mode. The experimental techniques used for assessing the photodamaging activity of this drug may be useful for screening of phototoxic compounds in the environment and for determining the active species involved.

Does topical flurbiprofen affect the pupillary response to acetylcholine?

Pre-operative topical non-steroidal anti-inflammatory drugs (NSAIDs) are known to be effective in maintaining pupillary dilation during cataract surgery. However, previous studies have suggested that pre-treatment with these agents interferes with the miosis produced by intraoperative acetylcholine injection. This study was designed to determine whether the pupillary response to acetylcholine injection is reduced following pre-operative topical flurbiprofen 0.03%. Pupil diameters were measured with a millimetre rule, and the measurements verified using computerised image analysis of digitised video images. Eyes treated with flurbiprofen were compared with controls. There was no significant difference in pupillary diameter before corneal incision, but following aspiration of soft lens matter and insertion of intraocular lens the pupil was significantly larger in the flurbiprofen group (p = 0.002). At 1.0, 2.5 and 5.0 minutes following injection of acetylcholine no significant difference in the degree of miosis was detected. This study confirms that topical flurbiprofen maintains dilation during cataract surgery, and does not find any evidence to suggest that intra-operative response to acetylcholine is reduced.

Molecular mechanism of drug photosensitization. 5. Photohemolysis sensitized by Suprofen

Red blood cell lysis photosensitized by Suprofen (SPF) and the photolysis of the drug were investigated. The photohemolysis process occurs at a higher rate in anaerobic than aerobic conditions. The effect of additives demonstrates the involvement of free radicals and, to a lesser extent, singlet oxygen and hydroxyl radicals in the process. Photolysis of the drug at 310-390 nm in deaerated buffered solutions (pH 7.4) leads to a decarboxylation process with the formation of p-ethylphenyl 2-thienyl ketone (I), whereas in aerated solutions formation of photoproduct I and of the photoproducts p-acetylphenyl 2-thienyl ketone (II) and p-(1-hydroxyethyl)phenyl-2-thienyl ketone (III) occurs. The photodegradation products, which were separated and characterized, show a moderate lytic and photolytic activity. The rate of SPF photodegradation decreases in the presence of oxygen and increases in the presence of hydrogen donors. The overall results lead us to propose a mechanism of SPF photodegradation and a hemolysis scheme in which cell damage is provoked principally by the direct attack of drug radicals and secondarily by singlet oxygen and hydroxyl radicals.