Stable phosphatidylcholine-bile salt mixed micelles enhance oral absorption of paclitaxel: preparation and mechanism in rats

Fast In Vitro Release and In Vivo Absorption of an Anti-Schizophrenic Drug Paliperidone from Its Soluplus®/TPGS Mixed Micelles

The purpose of this study was to develop a drug delivery system for paliperidone (PPD) in order to provide a more effective therapeutic strategy for patients with acute schizophrenia. PPD-loaded Soluplus®/TPGS mixed micelles (PPD-S/T-MM) were prepared using the thin-film hydration method. The critical micelle concentration (CMC) of blank S/T-MM was 4.77 × 10-2 mg/mL. PPD presented much higher solubility in PPD-S/T-MM formulation than that in pure water. The particle size of blank or drug loaded S/T-MM was around 60 nm. The polydispersity index (PDI) was less than 0.1. PPD-S/T-MM presented a nearly spherical shape under transmission electron microscopy. The encapsulation efficiency (EE%) of PPD-S/T-MM was higher than 94%. Based on the analysis of XRD and DSC, it was proved that PPD was incorporated in the core of the mixed micelles as amorphous dispersion or solid solution. PPD-S/T-MM were stable when they were undergoing dilution with water and the change of environmental pH. Although PPD-S/T-MM showed lower rates to release PPD than those from PPD raw material in acidic solution, they provided faster release rates in neutral conditions than those from PPD raw material who only showed modest dissolution in the same neutral condition. This proves that PPD-S/T-MM can release PPD in a more controlled manner. After oral administration of PPD-S/T-MM (dose of PPD, 6 mg/kg) in rats, the plasma concentration of PPD increased rapidly: Tmax was 0.83 ± 0.29 h, and Cmax was 844.33 ± 93.73 ng/mL. Oral administration of PPD suspension resulted in longer Tmax and lower Cmax. The relative oral bioavailability was about 158% for PPD-S/T-MM over PPD suspension. These findings confirm that PPD-S/T-MM can provide faster release in neutral conditions and better oral absorption in rats than those from PPD raw material, which should potentially benefit patients with acute schizophrenia.

Case ReportPaclitaxel-loaded TPGS2k/Gelatin-grafted Cyclodextrin/Hyaluronic acid-grafted Cyclodextrin nanoparticles for oral bioavailability and targeting enhancement

The clinical applications of paclitaxel (PTX), a natural compound with broad-spectrum antitumor effects, have been markedly limited owing to its poor oral bioavailability and lack of targeting ability. Recently, several drug carriers, such as TPGS_2k, gelatin (Gel), cyclodextrin (CD), and hyaluronic acid (HA), have been identified as promising enhancers of drug efficacy. Therefore, Gel-grafted CD (GEL-CD) and HA-grafted CD (HA-CD) were synthesized via grafting, and PTX-loaded TPGS_2k/GEL-CD/HA-CD nanoparticles (TGHC-PTX-NPs) were successfully prepared using the ultrasonic crushing method. The mean particles size, polydispersity index, and Zeta potential of TGHC-PTX-NPs were 253.57 ± 2.64 nm, 0.13 ± 0.03, and 0.087 ± 0.005 mV, respectively. TGHC-PTX-NPs with an encapsulation efficiency of 61.77 ± 0.47% and a loading capacity of 6.86 ± 0.32% appeared round and uniformly dispersed based on transmission electron microscopy. In vitro release data revealed that TGHC-PTX-NPs had good sustained-release properties. Further, TGHC-PTX-NPs had increased the targeted uptake by HeLa cells as HA can specifically bind to the CD44 receptor at the cell surface, and its intestinal absorption is related to caveolin-mediated endocytosis. The pharmacokinetic results indicated that TGHC-PTX-NPs significantly enhanced the absorption of PTX in vivo compared to the PTX suspension, with a relative bioavailability of 227.21%. Such findings indicate the potential of TGHC-PTX-NPs for numerous clinical applications.

d-α-Tocopheryl polyethylene glycol succinate/Solutol HS 15 mixed micelles for the delivery of baohuoside I against non-small-cell lung cancer: optimization and in vitro, in vivo evaluation

Baohuoside I, extracted from the Herba epimedii, is an effective but a poorly soluble antitumor drug. To improve its solubility, formulation of baohuoside I-loaded mixed micelles with d-α-tocopheryl polyethylene glycol succinate and Solutol HS 15 (BTSM) has been developed in this study. We performed a systematic comparative evaluation of the antiproliferative effect, cellular uptake, antitumor efficacy, and in vivo tumor targeting of these micelles using non-small-cell lung cancer (NSCLC) A549 cells. Results showed that the obtained micelles have a mean particle size of ~62.54 nm, and the size of micelles was narrowly distributed. With the improved cellular uptake, BTSM displayed a more potent anti-proliferative action on A549 cell lines than baohuoside I; half-maximal inhibitory concentration was 7.83 vs 20.37 µg/mL, respectively. The antitumor efficacy test in nude mice showed that BTSM exhibited significantly higher antitumor activity against NSCLC with lesser toxic effects on normal tissues. The imaging study for in vivo targeting demonstrated that the mixed micelles formulation achieved effective and targeted drug delivery. Therefore, BTSM might be a potential antitumor formulation.

Mechanism of enhanced antiosteoporosis effect of circinal-icaritin by self-assembled nanomicelles in vivo with suet oil and sodium deoxycholate

BACKGROUND

Circinal-icaritin (CIT), one new active aglycone of Epimedium, can exert a beneficial effect on osteoporotic bone. However, its low bioavailability limits its clinical efficacy for the treatment of osteoporosis.

MATERIALS AND METHODS

In this paper, suet oil (SO) was used to improve the oral bioavailability of CIT and enhance its antiosteoporosis effect and absorption. After oral administration of CIT together with SO, the CIT and SO self-assembled into nanomicelles under the action of sodium deoxycholate (DOC) by bile secretion. The antiosteoporosis effects of the CIT-SO-DOC nanomicelles were evaluated in osteoporotic rats by bone mineral density, serum biochemical markers, bone microarchitecture, bone biomechanical properties, and related protein and gene expressions. We examined the bioavailability of CIT and its nanomicelles in vivo, and subsequently the nanomicelles were verified using transmission electron microscopy. Finally, we evaluated absorption across a rat intestinal perfusion model.

RESULTS

Compared with CIT, in the CIT-SO groups, protein and messenger ribonucleic acid expressions of osteoprotegerin were increased, while expressions of receptor activator of nuclear factor-κB ligand in bone tissue were decreased; bone-turnover markers in serum of hydroxyproline, alkaline phosphatase, tartrate-resistant acid phosphatase 5b, and receptor activator of nuclear factor-κB ligand levels were decreased, while osteoprotegerin and osteocalcin levels were increased; and trabecular bone mass, microarchitecture, and bone biomechanical strength were enhanced. The relative bioavailabilities of CIT-SO high dosage, CIT-SO medium dosage, and CIT-SO low dosage (area under concentration-time curve [AUC]0-∞) compared with that of raw CIT high dosage, CIT medium dosage, and CIT low dosage (AUC0-∞) were 127%, 121%, and 134%, respectively. The average particle size of CIT-DOC was significantly decreased after adding SO (P<0.01), and the intestinal permeability coefficients of CIT-SO-DOC nanomicelles in the duodenum, jejunum, ileum, and colon were all significantly improved (P<0.01).

CONCLUSION

The increased antiosteoporosis effects and bioavailability of CIT-SO-DOC self-assembled nanomicelles were due to an increase in absorption of CIT by reducing the particle sizes of CIT. SO may be a practical oral carrier for antiosteoporosis drugs with low bioavailability.