Tannic acid is a chief gallo-tannin belonging to the hydrolysable tannins extracted from gall nuts and other plant sources. A myriad of pharmaceutical and biological applications in the medical field has been well recognized to tannic acid. Among these effects, potential anticancer activities against several solid malignancies such as liver, breast, lung, pancreatic, colorectal and ovarian cancers have been reported. Tannic acid was found to play a maestro-role in tuning several oncological signaling pathways including JAK/STAT, RAS/RAF/mTOR, TGF-β1/TGF-β1R axis, VEGF/VEGFR and CXCL12/CXCR4 axes. The combinational beneficial effects of tannic acid with other conventional chemotherapeutic drugs have been clearly demonstrated in literature such as a synergistic anticancer effect and enhancement of the chemo-sensitivity in several resistant cases. Yet, clinical applications of tannic acid have been limited owing to its poor lipid solubility, low bioavailability, off-taste, and short half-life. To overcome such obstacles, novel drug delivery systems have been employed to deliver tannic acid with the aim of improving its applications and/or efficacy against cancer cells. Among these drug delivery systems are several types of organic and metallic nanoparticles. In this review, the authors focus on the molecular mechanisms of tannic acid in tuning several neoplastic diseases as well as novel drug delivery systems that can be used for its clinical applications with an attempt to provide a systemic reference to promote the development of tannic acid as a cheap drug and/or drug delivery system in cancer management.

Anorectal diseases, such as hemorrhoids, are bothersome benign conditions that warrant special attention. The design of an optimized vesicular system for localized rectal delivery can be a suitable conservative treatment. The feasibility of preparing proniosomes using different types of Gelucires®, in combination with Span^® 60 as binary mixtures of nonionic surfactants, was checked, then the prepared proniosomes using Span 60 or Span 60/Gelucire were compared to conventional niosomes through investigations comprising the following: encapsulation efficiency (EE%); particle-size analysis; transmission electron microscopy; zeta potential (Z), and in vitro release study and ex vivo permeation study using excised rat rectum. All preparations showed satisfactory stability (Z >30 mV), particle size <300 nm with niosomes showing the lowest EE%, and the largest particle size, together with the least amount of drug released or accumulated in the rectal walls. Span 60/Gelucire proniosomes exhibited lower particle size as well as better release and permeation results, compared to Span 60 proniosomes. Span 60/Gelucire 44/14 (2:1) proniosomes attained the highest percentage of drug released (98.39%) and drug deposition in the rectal walls (86.26%) after 8 hours, which therefore seems to be the most suitable formula able to achieve targeted therapeutic efficacy, aiming to improve the patient’s quality of life.

The use of (PEG)-grafted materials has a positive impact on drug delivery. In this study we designed PEGylated lipid nanocarriers (PLN) loaded with curcumin (Cur) to target skin cancer by photodynamic therapy. Cur is a polyphenolic compound having vast biological effects masked due to its low aqueous solubility. PLN were prepared using Tefose 1500 with different surfactants. PLN3, containing Tween 80, had the smallest particle size (167.60 ± 15.12 nm), Z = − 26.91 mV and, attained the highest drug release (Q24 = 75.02 ± 4.61% and Q48 = 98.25 ± 6.89%). TEM showed spherical, well-separated nanoparticles. The dark and photo-cytotoxicity study on a human skin cancer cell line (A431) revealed that, at all tested concentrations, the viability of cells treated with PLN3 was significantly lower than those treated by Cur suspension and, it decreased upon irradiation by blue light (410 nm). The amount of Cur extracted from the skin of mice treated by PLN3 was twice that of mice treated by aqueous drug suspension, this was confirmed by the increase in fluorescence intensity measured by confocal laser microscopy. Histopathological studies showed that PLN3 could extend Cur effect to deeper skin layers, especially after irradiation. This study highlights the possible efficacy of curcumin-loaded PEGylated lipidic nanoparticles to combat skin cancer by photodynamic therapy.