Solid dispersion-based pellet for colon delivery of tacrolimus through time- and pH-dependent layer coating: preparation, in vitro and in vivo studies

Preparation and Evaluation of Auxiliary Permeable Microneedle Patch Composed of Polyvinyl Alcohol and Eudragit NM30D Aqueous Dispersion

Poor transdermal permeability limits the possibility of most drug delivery through the skin. Auxiliary permeable microneedles (AP-MNs) with a three-dimensional network structure can effectively break the skin stratum corneum barrier and assist in the transdermal delivery of active ingredients. Herein, we propose a simple method for preparing AP-MNs using polyvinyl alcohol and Eudragit NM30D for the first time. To optimize the formulation of microneedles, the characteristics of swelling properties, skin insertion, solution viscosity, and needle integrity were systematically examined. Additionally, the morphology, mechanical strength, formation mechanism, skin permeability, swelling performance, biocompatibility, and in vitro transdermal drug delivery of AP-MNs were evaluated. The results indicated that the microneedles exhibited excellent mechanical-strength and hydrogel-forming properties after swelling. Further, it proved that a continuous and unblockable network channel was created based on physical entanglement and encapsulation of two materials. The 24 h cumulative permeation of acidic and alkaline model drugs, azelaic acid and matrine, were 51.73 ± 2.61% and 54.02 ± 2.85%, respectively, significantly enhancing the transdermal permeability of the two drugs. In summary, the novel auxiliary permeable microneedles prepared through a simple blending route of two materials was a promising and valuable way to improve drug permeation efficiency.

99mTc-labelled and pH-awakened microbeads entrapping surface-modified lipid nanoparticles for the augmented effect of oxaliplatin in the therapy of colorectal cancer

AIM

This study was aimed to develop Eudragit S100-coated, pH-awakened microbeads (MBs) encapsulating folic acid (FA)-modified tristearin solid lipid nanoparticles (SLNs) loaded with oxaliplatin (OP). Afterward, these formulations were evaluated (in vitro and in vivo) for their potential against colorectal cancer (CRC).

METHODS

The SLNs were synthesised by employing the solvent diffusion technique and then they were entrapped in the MBs. The prepared uncoupled and coupled SLNs (SLN-OP and FA-SLN-OP, respectively) were examined for in vitro cytotoxicity effect against COLO-205. Gamma-scintigraphy study was used for determining biodistribution (in vivo) of drug in different organs through MBs.

RESULTS

Outcomes for FA-SLN-OP revealed more cytotoxicity (50% inhibitory concentration [IC₅₀] = 6.8 µg/ml) against COLO-205 cells (in vitro) than OP solution (IC₅₀ = 8.0 µg/ml) and SLN-OP (IC₅₀= 7.5 µg/ml). MBs were also investigated in vivo using Gamma-scintigraphy study. After 48 h study, ^99mTc-EuB-FA-SLN-OP confirmed an elevated level of drug in the colonic tumour, which was found significantly (p< 0.0001) higher than that of ^99mTc-EuB-SLN-OP.

CONCLUSIONS

In conclusion, developed MBs formulation (^99mTc-EuB-FA-SLN-OP) suggested promising results against therapy of CRC using dual targeting (i.e. ligand-directed and pH-awakened) approach.