Enhanced anti-inflammatory effects of nanoencapsulated diclofenac

This study was conducted to compare the anti-inflammatory efficacy of nanoencapsulated and free-form diclofenac in rat. Diclofenac-loaded liposomes were prepared using the proliposome method. The anti-inflammatory effects of nanoencapsulated and free diclofenac were evaluated using the carrageenan-induced paw edema, formalin-induced paw licking and cotton-pellet-induced granuloma tests in vivo. For carrageenan-induced paw edema, 2 and 20 mg/kg liposome-encapsulated diclofenac showed significant paw volume reduction compared to free form diclofenac of equivalent dosage groups. In the formalin test, significant reduction in paw-licking time was observed in late phase for both liposome-encapsulated and free-form diclofenac (2 and 20 mg/kg) with the percentage of inhibition of 28.62, 60.17% for free-form diclofenac and 31.45, 78.84% for liposome-encapsulated diclofenac, respectively. In cotton-pellet-induced granuloma test 20 mg/kg free-form diclofenac showed significant reduction in the size of granuloma in both transudative and granuloma weight with percentage of inhibition of 42.93 and 49.26%, respectively, when compared to controls. Interestingly, 20 mg/kg nanoencapsulated diclofenac showed a larger reduction of the parameter with percentage of inhibition of 48.43 and 63.55%, respectively. Collectively, these results indicated that nanoencapsulated diclofenac exhibited statistically higher efficacy than free-form diclofenac when orally administered. Hence, clinical dosage may be reduced thereby reducing the drug's adverse effects

Evaluation of antinociceptive activity of nanoliposome-encapsulated and free-form diclofenac in rats and mice

Diclofenac is a nonsteroidal anti-inflammatory drug (NSAID) that exhibits anti-inflammatory, antinociceptive, and antipyretic activities. Liposomes have been shown to improve the therapeutic efficacy of encapsulated drugs. The present study was conducted to compare the antinociceptive properties between liposome-encapsulated and free-form diclofenac in vivo via different nociceptive assay models. Liposome-encapsulated diclofenac was prepared using the commercialized proliposome method. Antinociceptive effects of liposome-encapsulated and free-form diclofenac were evaluated using formalin test, acetic acid-induced abdominal writhing test, Randall–Selitto paw pressure test, and plantar test. The results of the writhing test showed a significant reduction of abdominal constriction in all treatment groups in a dose-dependent manner. The 20 mg/kg liposome-encapsulated diclofenac demonstrated the highest antinociceptive effect at 78.97% compared with 55.89% in the free-form group at equivalent dosage. Both liposome-encapsulated and free-form diclofenac produced significant results in the late phase of formalin assay at a dose of 20 mg/kg, with antinociception percentages of 78.84% and 60.71%, respectively. Significant results of antinociception were also observed in both hyperalgesia assays. For Randall–Sellito assay, the highest antinociception effect of 71.38% was achieved with 20 mg/kg liposome-encapsulated diclofenac, while the lowest antinociceptive effect of 17.32% was recorded with 0 mg/kg liposome formulation, whereas in the plantar test, the highest antinociceptive effect was achieved at 56.7% with 20 mg/kg liposome-encapsulated diclofenac, and the lowest effect was shown with 0 mg/kg liposome formulation of 8.89%. The present study suggests that liposome-encapsulated diclofenac exhibits higher antinociceptive efficacy in a dose-dependent manner in comparison with free-form diclofenac