[99mTc]Technetium-Labeled Niosomes: Radiolabeling, Quality Control, and In Vitro Evaluation.

The aim of this research was to develop technetium-99m ([99mTc]Tc)-radiolabeled niosomes and evaluate the cancer cell incorporation capacity of radiolabeled niosomes. For this purpose, niosome formulations were developed by film hydration method, and prepared niosomes were characterized to particle size, polydispersity index (PdI), ζ-potential value, and image profile. Then, niosomes were radiolabeled with [99mTc]Tc using stannous salts (chloride) as a reducing agent. The radiochemical purity (RP) and stability in different mediums of the niosomes were assessed by ascending radioactive thin-layer chromatography (RTLC) and radioactive ultrahigh-performance liquid chromatography (R-UPLC) methods. Also, the partition coefficient value of radiolabeled niosomes was determined. The cell incorporation of [99mTc]Tc-labeled niosome formulations, as well as reduced/hydrolyzed (R/H)-[99mTc]NaTcO4 in the HT-29 (human colorectal adenocarcinoma) cells, was then assessed. According to the obtained results, the spherical niosomes had a particle size of 130.5 ± 1.364 nm, a PdI value of 0.250 ± 0.023, and a negative charge of -35.4 ± 1.06 mV. The niosome formulations were effectively radiolabeled with [99mTc]Tc using 500 µg mL-1 stannous chloride for 15 min, and RP was found to be over 95%. [99mTc]Tc-niosomes showed good in vitro stability in every system for up to 6 h. The log P value of radiolabeled niosomes was found as -0.66 ± 0.02. Compared to R/H-[99mTc]NaTcO4 (34.18 ± 1.56%), the incorporation percentages of [99mTc]Tc-niosomes (88.45 ± 2.54%) were shown to be higher in cancer cells. In conclusion, the newly developed [99mTc]Tc-niosomes showed good prototype for potential use in nuclear medicine imaging in the near future. However, further investigations, such as drug encapsulation and biodistribution studies, should be performed, and our studies are continuing.

The Designing of a Gel Formulation with Chitosan Polymer Using Liposomes as Nanocarriers of Amphotericin B for a Non-invasive Treatment Model of Cutaneous Leishmaniasis.

PURPOSE: Leishmaniasis is a disease caused by different Leishmania spp., which are transmitted to humans by a bite of infected female sand flies. Cutaneous leishmaniasis (CL, oriental sore), visceral leishmaniasis (VL), and mucocutaneous leishmaniasis (MCL) are three main clinical forms, however, only CL and VL are seen in Turkey. Cutaneous leishmaniasis is characterized by skin lesion(s) and is one of the most important vector-borne diseases in Turkey with over 2000 cases reported annually in 40 out of 81 provinces. The treatment is usually made invasively and painfully by intralesional injection of pentavalent antimony compounds. Non-invasive and innovative treatment methods are needed as aimed in this study. METHODS: In the present study, one of the classical antileishmanial drugs, amphotericin B (AmB), encapsulated in liposomes was evaluated using non-invasive design based on chitosan, which is a nontoxic, biocompatible and biodegradable polymer. To avoid the invasive effect of conventional intralesional needle application, the drug was encapsulated in liposomes and incorporated into a chitosan gel for applying topically on the skin lesion. The efficacy of encapsulation of amphotericin B into liposomes and the drug release from liposomes were studied. The chitosan gel was evaluated for viscosity, flowability, appearance and pH. The efficacy of the drug embedded into chitosan gel, liposomal AmB alone and chitosan gel alone in four different concentrations was also tested using Leishmania spp. promastigotes in vitro. RESULTS: The findings have shown that AmB was encapsulated into the liposomes with high efficiency (86.6%) and long-term physical and chemical stability. Therefore, designed liposomal formulation was suitable for sustained release. The appearance of the drug-embedded chitosan gel was transparent and appropriate. Chitosan gels showed non- Newtonian behavior and plastic flow. The liposomal AmB also showed higher efficacy with no parasites in all concentrations while drug embedded into chitosan gel and chitosan gel alone were effective in two higher concentrations. The lower efficacy of the drug-embedded chitosan gel in 24 h in in-vitro study was probably due to slow release of the drug. CONCLUSION: The gel design created in this study will provide ease of use for the lesions of CL patients that do not have a specific number, size, and shape. Follow-up studies by the ex-vivo macrophage infection model with Leishmania intracellular amastigote forms and Leishmania-infected animal models are needed to understand the present design's efficacy better.

Investigation of acute effects of Hypericum perforatum (St. John's Wort-Kantaron) treatment in experimental thermal burns and comparison with silver sulfadiazine treatment.

BACKGROUND: Hypericum perforatum (HP) (St. John's Wort-Kantaron) has been used widely for the treatment of burn injuries for many years in traditional Turkish medicine. The aim of study was to investigate HP treatment in experimental thermal burns and compare it with silver sulfadiazine (SS) treatment. METHODS: Thirty-five rats were randomly assigned to one of the five groups, 7 rats in each. A second-degree thermal burn was created on the dorsal sites of rats by exposing an area of 4×4 cm to 100 °C boiled water for 10 seconds. All groups were provided with irrigation for three (3) minutes with 50 cc saline solution (SS). Group 1 (Control Group) was not administered any treatment. Group 2 (Burn Control Group) was administered only irrigation, Group 3 (topical silver sulfadiazine [SS]) was administered SS twice a day, Group 4 (the Topical HP Group) was administered HP four times a day (every six hours), Group 5 (treatment with agent -gel-) was administered other topical material used for the preparation of HP four times a day (every six hours). Wound site healing on the skin was histopathologically evaluated. RESULTS: It was found that collagen discoloration of the HP treatment group was localized in the lower part of the epidermal layer and did not go up to the depth of dermis compared to the other groups, and epidermis, hair follicles and sebaceous glands remained protected compared to the groups administered burn, gel and SS in every hour of the experiment and it was the group closest to the control group structurally. It was determined that the epidermal thickness and the number of vessels of the HP Group were significantly higher compared to the other groups (p<0.05), which was the group closest to the control group in terms of these parameters and these numbers did not show any difference within hours (p>0.05). The number of degenerated hair follicles in the HP Group was significantly less than the other groups (p <0.05), and it was determined that the total number of hair follicles significantly increased in the twenty-fourth (p<0.05) and this number did not differ by the control group (p>0.05). CONCLUSION: Administration of HP four times a day within the first 24 hours is clearly effective in wound healing in the experimental thermal second degree burn modality and is significantly superior to SS treatment.