Correction: Ci et al. Enhanced Delivery of Imatinib into Vaginal Mucosa via a New Positively Charged Nanocrystal-Loaded in Situ Hydrogel Formulation for Treatment of Cervical Cancer. Pharmaceutics 2019, 11, 15.

In the original publication [...].

Synergistic Antitumor Effects on Drug-Resistant Breast Cancer of Paclitaxel/Lapatinib Composite Nanocrystals.

Drug resistance presents serious difficulties for cancer treatment. A combination of paclitaxel (PTX) and lapatinib (LAPA) shows potentials in multiple drug resistant cancers in the clinic, but it is almost impossible to deliver these two drugs to the tumor at the same time with the best proportion by simple co-administration of the respective current formualtions for their different pharmacokinetic profiles. Here composite nanocrystals of PTX and LAPA (cNC) were designed with a ratio of 2:1 (w/w), which was their intracellular ratio at the best synergistic efficacy on a drug-resistant cancer cell line (MCF-7/ADR). Such cNC were prepared using a bottom-up method to achieve a nearly spherical appearance and a narrow size distribution of 95.1 ± 2.1 nm. For nanocrystal stabilization, Polyethylene glycol (PEG) coating was introduced into the cNC via polydopamine (PDA) coating in order to get a PEGylated composite nanocrystal (cNC@PDA-PEG) with nanoscale size (170.5 ± 1.4 nm), considerable drug loading (PTX: 21.33 ± 1.48%, LAPA: 10.95 ± 1.24%) and good stability for at least 4 days in plasma-containing buffers. Differential scanning calorimeter (DSC) and XRD data both indicated the different crystalline states of the cNC as well as the cNC@PDA-PEG in comparison with bulk drugs. In vitro release data showed that PTX and LAPA were gradually and completely released from cNC@PDA-PEG in 3 days, while drug release from bulk drugs or cNC was only 30%. cNC@PDA-PEG also showed negligible hemolysis in vitro. Cellular uptake experiments in the MCF-7/ADR cell line showed that the nanocrystals entered the cells in a complete form through endocytosis and then released the drug in the cell. cNC@PDA-PEG inhibits the growth of this drug-resistant cell more effectively than the unmodified version (cNC). In summary, PEGylated PTX and LAPA composite nanocrystals showed the potential for treament of drug-resistant tumors by simultaneously delivering two drugs to tumor cells with the best proportion.

Enhanced Delivery of Imatinib into Vaginal Mucosa via a New Positively Charged Nanocrystal-Loaded in Situ Hydrogel Formulation for Treatment of Cervical Cancer.

The present study was carried out to investigate the potential of cationic functionalization on imatinib nanocrystals to improve the mucoadhesiveness and, thus, delivery to the lesion of cervicovaginal tumors. Amino-group-functionalized imatinib nanocrystals (NC@PDA-NH2) were prepared with near-spheroid shape, nanoscale size distribution, positive zeta potential, and relatively high drug content with the aid of the polydopamine-coating technique. Efficient interaction between NC@PDA-NH2 and mucin was proven by mucin adsorption which was related to the positive zeta-potential value of NC@PDA-NH2 and the change in the size distribution on mixing of NC@PDA-NH2 and mucin. Cellular uptake, growth inhibition, and apoptosis induction in cervicovaginal cancer-related cells demonstrated the superiority of NC@PDA-NH2 over unmodified nanocrystals. For practical intravaginal administration, NC@PDA-NH2 was dispersed in Pluronic F127-based thermosensitive in situ hydrogel, which showed suitable gelation temperature and sustained-release profiles. In comparison with unmodified nanocrystals, NC@PDA-NH2 exhibited extended residence on ex vivo murine vaginal mucosa, prolonged in vivo intravaginal residence, and enhanced inhibition on the growth of murine orthotopic cervicovaginal model tumors indicated by smaller tumor size, longer median survival time, and more intratumor apoptosis with negligible mucosal toxicity. In conclusion, cationic functionalization endowed NC@PDA-NH2 significant mucoadhesiveness and, thus, good potential against cervicovaginal cancer via intravaginal administration.

RGD-modified PEGylated paclitaxel nanocrystals with enhanced stability and tumor-targeting capability.

Nanocrystals has been constructed for insoluble drugs as a novel type of nanoscale drug delivery systems with high drug loading. How to prepare nanocrystals with good stability and tumor targeting capability is still challenging. This study was to modify paclitaxel nanocrystals with polyethylene glycol (PEG) for stabilization and RGD peptide for tumor targeting. Inspired by the structure of mussel's foot protein, polydopamine (PDA) was introduced to the drug delivery system for the modification of nanocrystals. Briefly, PDA was coated on the surface of nanocrystals to form a reaction platform for further PEGylation and RGD peptide conjugation. PEGylated nanocrystals with RGD peptide modification (NC@PDA-PEG-RGD) were prepared with near-spheroid shape, drug loading 45.12 ±â€¯1.81% and a hydrodynamic diameter 419.9 ±â€¯80.9 nm. The size of NC@PDA-PEG-RGD remained basically unchanged for at least 72 h in the presence of plasma while the size of unmodified nanocrystals (NC) increased and exceeded 1000 nm in 12 h. Cellular uptake and cellular growth inhibition experiments using the lung cancer cell line A549 demonstrated the superiority of NC@PDA-PEG-RGD over NC or PEGylated nanocrystals without RGD modification (NC@PDA-PEG). In A549 model tumor bearing-mice, NC@PDA-PEG-RGD showed significantly higher intratumor accumulation and slower tumor growth than NC@PDA-PEG or free paclitaxel. In summary, our study suggested the superiority of RGDmodified PEGylated paclitaxel nanocrystals as a lung cancer-targeted delivery system and the potential of PDA coating technique for targeting functionalization of nanocrystals.