Preparation and in vitro/in vivo evaluation of a self-microemulsifying drug delivery system containing chrysin

Self-Nanoemulsion Intrigues the Gold Phytopharmaceutical Chrysin: In Vitro Assessment and Intrinsic Analgesic Effect

Chrysin is a natural flavonoid with a wide range of bioactivities. Only a few investigations have assessed the analgesic activity of chrysin. The lipophilicity of chrysin reduces its aqueous solubility and bioavailability. Hence, self-nanoemulsifying drug delivery systems (SNEDDS) were designed to overcome this problem. Kollisolv GTA, Tween 80, and Transcutol HP were selected as oil, surfactant, and cosurfactant, respectively. SNEDDS A, B, and C were prepared, loaded with chrysin (0.1%w/w), and extensively evaluated. The optimized formula (B) encompasses 25% Kollisolv GTA, 18.75% Tween 80, and 56.25% Transcutol HP was further assessed. TEM, in vitro release, and biocompatibility towards the normal oral epithelial cell line (OEC) were estimated. Brain targeting and acetic acid-induced writhing in a mouse model were studied. After testing several adsorbents, powdered SNEDDS B was formulated and evaluated. The surfactant/cosurfactant (S/CoS) ratio of 1:3 w/w was appropriate for the preparation of SNEDDS. Formula B exhibited instant self-emulsification, spherical nanoscaled droplets of 155.4 ± 32.02 nm, and a zeta potential of - 12.5 ± 3.40 mV. The in vitro release proved the superiority of formula B over chrysin suspension (56.16 ± 10.23 and 9.26 ± 1.67%, respectively). The biocompatibility of formula B towards OEC was duplicated (5.69 ± 0.03 µg/mL). The nociceptive pain was mitigated by formula B more efficiently than chrysin suspension as the writhing numbers reduced from 8.33 ± 0.96 to 0 after 60 min of oral administration. Aerosil R972 was selected as an adsorbent, and its chemical compatibility was confirmed. In conclusion, our findings prove the therapeutic efficacy of chrysin self-nanoemulsion as a potential targeting platform to combat pain.

Application of Design of Experiments in the Development of Self-Microemulsifying Drug Delivery Systems

Oral delivery has become the route of choice among all other types of drug administrations. However, typical chronic disease drugs are often poorly water-soluble, have low dissolution rates, and undergo first-pass metabolism, ultimately leading to low bioavailability and lack of efficacy. The lipid-based formulation offers tremendous benefits of using versatile excipients and has great compatibility with all types of dosage forms. Self-microemulsifying drug delivery system (SMEDDS) promotes drug self-emulsification in a combination of oil, surfactant, and co-surfactant, thereby facilitating better drug solubility and absorption. The feasible preparation of SMEDDS creates a promising strategy to improve the drawbacks of lipophilic drugs administered orally. Selecting a decent mixing among these components is, therefore, of importance for successful SMEDDS. Quality by Design (QbD) brings a systematic approach to drug development, and it offers promise to significantly improve the manufacturing quality performance of SMEDDS. Furthermore, it could be benefited efficiently by conducting pre-formulation studies integrated with the statistical design of experiment (DoE). In this review, we highlight the recent findings for the development of microemulsions and SMEDDS by using DoE methods to optimize the formulations for drugs in different excipients with controllable ratios. A brief overview of DoE concepts is discussed, along with its technical benefits in improving SMEDDS formulations.

Preparation of 2-Methoxyestradiol Self-emulsified Drug Delivery System and the Effect on Combination Therapy with Doxorubicin Against MCF-7/ADM Cells

Due to the poor solubility and bioavailability of 2-methoxyestradiol (2-ME), 2-ME emulsified drug delivery system (2-ME-SEDDS) was designed and characterized. After dilution with 5% glucose, 2-ME-SEDDS formed fine emulsions with mean diameter of 171 ± 14 nm and zeta potential of - 7.4 ± 0.6 mV. The cytotoxicity of 2-ME-SEDDS against MCF-7 and MCF-7/ADM cells was considerable to that of free 2-ME, and the half maximal inhibitory concentration ran up to 195 µg/mL on MCF-7/ADM cells. In order to gain a satisfactory inhibition effect on MCF-7/ADM cells, 2-ME-SEDDS combined with doxorubicin was used. It is worth noting that the combination of 2-ME-SEDDS and doxorubicin displayed a superior synergistic effect with a combined index of 0.62. And the cellular uptake of doxorubicin by MCF-7/ADM cells in the combination group was significantly higher than that of doxorubicin treatment group. The study preliminarily suggested that 2-ME-SEDDS could increase the cellular uptake of doxorubicin by MCF-7/ADM cells and the synergistic effect may be attributed to the increased cellular uptake of doxorubicin under the influence of 2-ME-SEDDS. In conclusion, SEDDS was an alternative and promising formulation for 2-ME. The combination therapy with synergistic effect by the combination of 2-ME-SEDDS and doxorubicin seems to be a promising strategy to potentiate anti-tumor efficiency against MCF-7/ADM, even other multidrug resistance tumors.