Nanocrystals, a carrier-free colloidal delivery system in nano-sized range, is an interesting approach for poorly soluble drugs. Nanocrystals provide special features including enhancement of saturation solubility, dissolution velocity and adhesiveness to surface/cell membranes. Several strategies are applied for nanocrystals production including precipitation, milling, high pressure homogenization and combination methods such as NanoEdge™, SmartCrystal and Precipitation-lyophilization-homogenization (PLH) technology. For oral administration, many publications reported useful advantages of nanocrystals to improve in vivo performances i.e. pharmacokinetics, pharmacodynamics, safety and targeted delivery which were discussed in this review. Additionally, transformation of nanocrystals to final formulations and future trends of nanocrystals were also described

Self-nanoemulsifying drug delivery systems (SNEDDS) have been used to improve the oral bioavailability of various drugs. In the current study, apigenin was developed as SNEDDS to solve its dissolution problem and enhance oral bioavailability and antioxidant potential. SNEDDS were prepared by mixing Gelucire 44/14, Tween 80, and PEG 400 under controlled conditions. The droplet of diluted SNEDDS demonstrated a spherical shape with a size of less than 100 nm and a neutral charge. The very fast self-emulsification was obtained within 32 s, and the transmittance values exceeded 99%. The highest drug loading was 90.10 ± 0.24% of the initial load with the highest %encapsulation efficiency of 84.20 ± 0.03%. FT-IR and DSC spectra showed no interaction between components. The dissolution in buffer pH 1.2, 4.5, and 6.8 showed significantly higher dissolved apigenin than the apigenin coarse powder. The dissolution profiles were fitted to the Korsmeyer–Peppas kinetics. The cellular antioxidant activities in Caco-2 cells were approximately 52.25–54.64% compared to no treatment and were higher than the apigenin coarse powder (12.70%). Our work highlights the potential of SNEDDS to enhance the dissolution and permeability of apigenin and promote antioxidant efficacy, which has a strong chance of being developed as a bioactive compound for nutraceuticals.

Pumpkin seed oil (PSO)-loaded niosomes were prepared from Tween 20 and cholesterol by ethanol injection. Confocal microscopy showed better skin permeation and hair follicle accumulation of the niosomes compared to the PSO solution. The PSO-loaded niosomes inhibited 5α-reductase activity in DU-145 cells and hindered IL-6 activity in RAW 264.7 cells. These effects indicated the great potential of PSO-loaded niosomes to reduce hair loss. The hair scalp serum with PSO-loaded niosomes did not show irritation to reconstructed human skin. This formulation presented a significant decrease in the percentage of fallen hairs by 44.42% in the in vivo 60-second hair count experiment and a significant increase in the anagen to telogen (A/T) ratio (1.4-fold) in the TrichoScan^® evaluation after 8 weeks of treatment compared to the initial conditions, indicating the promising efficacy of PSO-loaded niosomes as a natural alternative for anti-hair loss therapy.