<p>Oral absorption and lymphatic transport of baicalein following drug–phospholipid complex incorporation in self-microemulsifying drug delivery systems</p>

Abstract

PurposeThe aims of this study were to prepare a baicalein self-microemulsion with baicalein-phospholipid complex as the intermediate (BAPC-SMEDDS) and to compare its effects with those of conventional baicalein self-microemulsion (CBA-SMEDDS) on baicalein oral absorption and lymphatic transport.MethodsTwo SMEDDS were characterized by emulsifying efficiency, droplet size, zeta potential, cloud point, dilution stability, physical stability, and in vitro release and lipolysis. Different formulations of 40 mg/kg baicalein were orally administered to Sprague-Dawley rats to investigate their respective bioavailabilities. The chylomicron flow blocking rat model was used to evaluate their lymphatic transport.ResultsThe droplet sizes of BAPC-SMEDDS and CBA-SMEDDS after 100x dilution were 9.6±0.2 nm and 11.3±0.4 nm, respectively. In vivo experiments indicated that the relative bioavailability of CBA-SMEDDS and BAPC-SMEDDS was 342.5% and 448.7% compared to that of free baicalein (BA). The AUC0–t and Cmax of BAPC-SMEDDS were 1.31 and 1.87 times higher than those of CBA-SMEDDS, respectively. The lymphatic transport study revealed that 81.2% of orally absorbed BA entered the circulation directly through the portal vein, whereas approximately 18.8% was transported into the blood via lymphatic transport. CBA-SMEDDS and BAPC-SMEDDS increased the lymphatic transport ratio of BA from 18.8% to 56.2% and 70.2%, respectively. Therefore, self-microemulsion not only significantly improves oral bioavailability of baicalein, but also increases the proportion lymphatically transported. This is beneficial to the direct interaction of baicalein with relevant immune cells in the lymphatic system and for proper display of its effects.ConclusionThis study demonstrates the oral absorption and lymphatic transport characteristics of free baicalein and baicalein SMEDDS with different compositions. This is of great significance to studies on lymphatic targeted delivery of natural immunomodulatory compounds.

Current approaches in lipid-based nanocarriers for oral drug delivery

“…Interestingly, this study revealed that < 20% of orally absorbed free baicalein entered the systemic circulation through the lymphatic system, whereas this transport, respectively, increased to > 56 and > 70.2% after the administration of SMEDDS loaded with the flavonoid or its phospholipid complex. Taken together, these results revealed the ability that phospholipids and SMEDDS stabilized by Tween 80 have to enhance the lymphatic uptake of poor-water soluble molecules [ 173 ]. Sangsen et al reported an increase of the oral bioavailability of oxyresveratrol by its encapsulation in SMEDDS, which was significantly higher than the improvement observed when Labrasol was used as surfactant.…”

“…Self-emulsifying systems have been developed in last years to increase the oral bioavailability of antiviral [144,145], cardiovascular [146][147][148][149][150], anti-tumour [151][152][153][154][155][156][157][158], antiemetic [159] or immunosuppressive [160] drugs, as well as of peptides [161][162][163][164][165], vitamins [166], nutraceuticals and natural compounds, such as resveratrol, curcumin or bruceine [167][168][169][170][171][172][173].…”

Nanoformulations of Ursolic Acid: A Modern Natural Anticancer Molecule

“…In addition, surfactants can increase the solubility of water-insoluble drugs and promote the entry of drugs into small intestinal epithelial cells. This constitutes nanoemulsion a delivery system that can improve the bioavailability of UA and has great potential for sustained drug release and tumor targeting ( Liao et al, 2019 ).…”

Improved Pharmacodynamic Potential of Rosuvastatin by Self-Nanoemulsifying Drug Delivery System: An in vitro and in vivo Evaluation

“…The low viscosity of developed nano-emulsion confirms its o/w type of nano-emulsion and vice-versa. 45 Estimation of Cloud Point It was measured after 100-times dilution of SNEDDS (1 g) submit your manuscript | www.dovepress.com…”