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The leaf extracts of three endemic species of Pandanus namely, P. luzonensis, P. panayensis, and P. simplex were investigated for their safety profile and anti-inflammatory property. The Approximate Lethal Dose (ALD) was established through acute oral toxicity test. Carrageenan-induced rat paw edema assay assessed the anti-inflammatory property. Each treatment group received assigned dose of extract (250, 500, 1000 mg/kg BW), 1% Tween 80 and diclofenac sodium (100 mg/kg BW) for the negative and positive control groups, respectively. The ethanol leaf extract P. panayensis at 500 mg/kg BW showed sustained inflammatory inhibition for 6 hours of observation with comparable inhibitory activity with diclofenac sodium (ave p=0.970). Histopathology of the inflamed paw tissues showed mild inflammation. IC50 against COX-1 and 2 are 610.69 ug/mL and >1000 ug/mL respectively against <10 ug/mL of Indomethacin as standard. These results suggest that all Pandanus leaf extracts have an ALD greater than 2000 mg/kg BW while P. payanensis extracts may serve as potential sources of anti-inflammatory agents. This activity may be contributed by flavonoids, steroids, terpenoids and fatty acid which were identified by Liquid Chromatography-Mass Spectrometry. [ABSTRACT FROM AUTHOR]

Etoricoxib, although exhibiting superior and selective anti-inflammatory properties, exhibits poor aqueous solubility which precludes its formulation into parenteral preparations. This study aims to increase the aqueous solubility of this drug by complexation with caffeine, an aromatic base known to exhibit a pi-pi stacked complex with aromatic drugs. The molar complexation between caffeine and etoricoxib was analyzed by phase solubility studies, Jacob's continuous variation, and Ardon's plots. Solid-state analyses and in vitro diffusion experiments were employed to analyze the optimized caffeine-etoricoxib complex (OCEC). The in vitro inhibitory properties of OCEC against cyclooxygenase 2 enzyme (COX-2) were compared to plain etoricoxib (PE). Phase solubility diagrams showed that the solubility of etoricoxib (0.25 M) was continuously elevated with increasing caffeine concentration as a result of complexation. Optimization experiments showed that caffeine complexes with etoricoxib at a 1:1 molar ratio. The effects of pH on degradation showed that etoricoxib within the OCEC is most stable at pH 7.4. The release of etoricoxib from OCEC follows super case 2 transport mechanisms with high diffusivity. In terms of in vitro inhibition against COX-2, OCEC (IC50 = 0.125 mcg/mL) is more potent than PE (IC50 = 3.1 mcg/mL). This study revealed that a 1:1 molar stacked complex between caffeine and etoricoxib drastically increases the aqueous solubility of the latter, a greater stability of the drug at pH 7.4, a Korsmeyer-Peppas diffusion kinetics involving non-Fickian drug release, and enhanced in vitro COX-2 inhibitory effects. [ABSTRACT FROM AUTHOR]