Synthesis, Characterization and Biocompatibility Evaluation of Novel Chitosan Lipid Micro-Systems for Modified Release of Diclofenac Sodium

The purpose of our study was the obtaining, characterization and biocompatibility estimation of novel carrier systems for diclofenac. Diclofenac is a potent nonsteroidal anti-inflammatory drug with frequent gastrointestinal side effects, impairing the quality of the patient's life. Original diclofenac-loaded micro-vesicles coated with chitosan were prepared and physico-chemical analyzed. We investigated their in vitro hemocompatibility and in vivo biocompatibility in rats. The animals were treated orally as follows: group 1 (Control): distilled water 0.3 mL/100 g body weight; Group 2 (CHIT): 0.3 mL/100 g body weight 0.5% chitosan solution; Group 3 (DCF): 15 mg/kg body weight diclofenac; Group 4 (DCF-ves): lipid vesicles loaded with diclofenac 15 mg/kg body weight. Blood samples were collected for assessing: red blood cells, hemoglobin, hematocrit and leukocyte formula. A series of specific parameters of the liver and kidney function, some markers of immune defense, as well as the activity of some enzymes involved in oxidative processes, were also investigated. At the end of the experiment, the animals were sacrificed and fragments of liver, kidney and stomach were collected for histopathological examination. No blood hemolysis was evidenced by the in vitro test with the administration of diclofenac vesicles. The animals treated with diclofenac lipid vesicles stabilized with chitosan did not display any notable differences in their hematological and biochemical profile compared to control animals. These data correlated with the histological results, which showed the absence of architectural changes in the examined tissues. Biological in vitro and in vivo evaluation revealed that the microvesicles containing diclofenac are biocompatible, with potential to be used as delivery systems to modify the drug release, thus making them an attractive candidate for biomedical applications.

Development of a novel nanoemulgel formulation containing cumin essential oil as skin permeation enhancer

Essential oils have been proposed as promising non-toxic transdermal permeation enhancers. Their use is limited because of their low water solubility. The use of nanotechnology-based strategies is one of the ways to overcome this limitation. This study aimed to explore the transdermal permeation enhancing capability of cumin essential oil in nanoemulgel systems containing diclofenac sodium. Cumin essential oil nanoemulsion was produced by high-pressure homogenization technique. The formulation was optimized by changing HLB values in a range of 9.65–16.7 using different surfactant mixtures, namely, Tween 20, Tween 80, and Span 80. Preparations were characterized by polydispersity index, droplet size, and zeta potential. Nanoemulsion with concentrations of 2 and 4% essential oil was incorporated into 0.75% Carbopol gel matrix to make nanoemulgel formulation, and its permeation enhancing effect was performed through Franz diffusion cells. Antinociceptive activities of the formulations were measured in thermal (tail-flick) and chemical (formalin) models of nociception in mice. Characterization exhibited that at HLB value of 9.65, the smallest particle size (82.20 ± 5.82 nm) was formed. By increasing the essential oil percentage in the nanoemulgel from 1 to 2%, the permeation of diclofenac increased from 28.39 ± 1.23 to 34.75 ± 1.07 µg/cm² at 24 h. The value of permeation from the simple gel (21.18 ± 2.51 µg/cm²) and the marketed product (22.97 ± 1.92 µg/cm²) was lower than the formulations containing essential oil. Nanoemulgel of diclofenac containing essential oil showed stronger antinociceptive effects in formalin and tail-flick tests than simple diclofenac gel and marketed formulation. In conclusion, the study proved that nanoemulgel formulation containing cumin essential oil could be considered as a promising skin enhancer to enhance the therapeutic effect of drugs.

Long-Lasting, Antinociceptive Effects of pH-Sensitive Niosomes Loaded with Ibuprofen in Acute and Chronic Models of Pain

Ibuprofen is one of the non-steroidal anti-inflammatory drugs (NSAIDs) widely used to treat pain conditions. NSAIDs encounter several obstacles to passing across biological membranes. To overcome these constraints, we decided to study the effects of a new pH-sensitive formulation of niosomes containing Polysorbate 20 derivatized by Glycine and loaded with ibuprofen (NioIbu) in several animal models of pain in mice. We performed two tests commonly used to study acute antinociceptive activity, namely the writhing test and the capsaicin test. Our results demonstrated that NioIbu, administered 2 h before testing, reduced nociception, whereas the free form of ibuprofen was ineffective. In a model of inflammatory pain, hyperalgesia induced by zymosan, NioIbu induced a long-lasting reduction in hyperalgesia in treated mice. In a model of neuropathic pain induced by sciatic nerve chronic constriction, NioIbu reduced both neuropathy-induced allodynia and hyperalgesia. The results obtained in our experiments suggest that pH-sensitive niosomes containing Polysorbate 20 derivatized by Glycine is an effective model for NSAIDs delivery, providing durable antinociceptive effects and reducing the incidence of side effects.