Solid Dispersion of Kaempferol: Formulation Development, Characterization, and Oral Bioavailability Assessment.

Kaempferol (KPF), an important flavonoid, has been reported to exert antioxidant, anti-inflammatory, and anticancer activity. However, this compound has low water solubility and hence poor oral bioavailability. This work aims to prepare a solid dispersion (SD) of KPF using Poloxamer 407 in order to improve the water solubility, dissolution rate, and pharmacokinetic properties KPF. After optimization, SDs were prepared at a 1:5 weight ratio of KPF:carrier using the solvent method (SDSM) and melting method (SDMM). Formulations were characterized by Fourier transform infrared spectroscopy (FTIR), X-ray diffractometry (XRD) analysis, differential scanning calorimetry (DSC), and scanning electron microscopy (SEM). The solubility in water of carried-KPF was about 4000-fold greater than that of free KPF. Compared with free KPF or the physical mixture, solid dispersions significantly increased the extent of drug release (approximately 100% within 120 min) and the dissolution rate. Furthermore, after oral administration of SDMM in rats, the area under the curve (AUC) and the peak plasma concentration (Cmax) of KPF from SDMM were twofold greater than those of free KPF (p < 0.05). In conclusion, SD with Poloxamer 407 is a feasible pharmacotechnical strategy to ameliorate the dissolution and bioavailability of KPF.

Validation of an HPLC-UV method for analysis of Kaempferol-loaded nanoemulsion and its application to in vitro and in vivo tests.

A simple and reliable HPLC-UV method for Kaempferol (KPF) determination in a Kaempferol-loaded nanoemulsion (KPF-NE), samples from mucosa permeation/retention studies, and murine brain was developed and validated according to international guidelines. The analyses were performed on a reversed-phase C18 column at 35°C and under UV detection at 368nm. The mobile phase was composed of methanol:formic acid 0.1% (75:25, v/v) and was eluted at an isocratic flow rate of 1.0mL/min. The method was selective and sensitive for KPF analysis in matrix extracts, and linear in the range of 0.25-7.5µg/mL. The method was also considered precise, accurate, and robust. The recovery rates of KPF from the porcine nasal mucosa and murine brain were higher than 85%. Low matrix effect was observed to determine KPF, including biological matrices. The applicability of the method was confirmed in all different approaches, i.e., quantification of KPF in nanoemulsion, in vitro permeation/retention of KPF across porcine nasal mucosa, and in vivo quantification of KPF in brain samples after nasal administration in rats. Thus, the method is effective and reliable to determine KPF in different real samples. The proposed method, therefore, provides a useful quantification approach to routine processes, to the development of drug delivery systems, and to KPF quantification in different biological matrices. Furthermore, the method is applicable in bioavailability studies and the developed formulation (KPF-NE) is suitable for preclinical trials in different brain disorders.

Nanoemulsions containing a synthetic chalcone as an alternative for treating cutaneous leshmaniasis: optimization using a full factorial design.

Nanoemulsions are drug delivery systems that may increase the penetration of lipophilic compounds through the skin, enhancing their topical effect. Chalcones are compounds of low water solubility that have been described as promising molecules for the treatment of cutaneous leishmaniasis (CL). In this context, the aim of this work was to optimize the development of a nanoemulsion containing a synthetic chalcone for CL treatment using a 2(2) full factorial design. The formulations were prepared by spontaneous emulsification and the experimental design studied the influence of two independent variables (type of surfactant - soybean lecithin or sorbitan monooleate and type of co-surfactants - polysorbate 20 or polysorbate 80) on the physicochemical characteristics of the nanoemulsions, as well as on the skin permeation/retention of the synthetic chalcone in porcine skin. In order to evaluate the stability of the systems, the antileishmanial assay was performed against Leishmania amazonensis 24 hours and 60 days after the preparation of the nanoemulsions. The formulation composed of soybean lecithin and polysorbate 20 presented suitable physicochemical characteristics (droplet size 171.9 nm; polydispersity index 0.14; zeta potential -39.43 mV; pH 5.16; and viscosity 2.00 cP), drug content (91.09%) and the highest retention in dermis (3.03 µg·g(-1)) - the main response of interest - confirmed by confocal microscopy. This formulation also presented better stability of leishmanicidal activity in vitro against L. amazonensis amastigote forms (half maximal inhibitory concentration value 0.32±0.05 µM), which confirmed the potential of the nanoemulsion soybean lecithin and polysorbate 20 for CL treatment.

DNMT3A Mutations in Patients with Acute Myeloid Leukemia in South Brazil.

Acute myeloid leukemia (AML) is a complex and heterogeneous hematopoietic tissue neoplasm. Several molecular markers have been described that help to classify AML patients into risk groups. DNA methyltransferase 3A (DNMT3A) gene mutations have been recently identified in about 22% of AML patients and associated with poor prognosis as an independent risk factor. Our aims were to determine the frequency of somatic mutations in the gene DNMT3A and major chromosomal translocations in a sample of patients with AML. We investigated in 82 samples of bone marrow from patients with AML for somatic mutations in DNMT3A gene by sequencing and sought major fusion transcripts by RT-PCR. We found mutations in the DNMT3A gene in 5 patients (6%); 3 were type R882H [corrected]. We found fusion transcripts in 19 patients, namely, AML1/ETO (n = 5; 6.1%), PML/RARα (n = 12; 14.6%), MLL/AF9 (0; 0%), and CBFß/MYH11 (n = 2; 2.4%). The identification of recurrent mutations in the DNMT3A gene and their possible prognostic implications can be a valuable tool for making treatment decisions. This is the first study on the presence of somatic mutations of the DNMT3A gene in patients with AML in Brazil. The frequency of these mutations suggests a possible ethnogeographic variation.