Safflower (Carthamus tinctorius L.) is a potent natural antioxidant because of active compounds such as quercetin (QU) and luteolin (LU). These components prevent damage to the skin caused by free radicals from UV rays. However, due to the poor solubility and transdermal permeation, the effectiveness of the compounds in showing their activity was limited. In this study, we develop solid lipid nanoparticle (SLN)-based hydrogel formulations to enhance the solubility and penetration of two bioactive compounds found in safflower petals extract (SPE). The hot emulsification-ultrasonication method was used to produce SLNs, and to obtain high antioxidant activity, 100% v/v ethanol was used in the extraction procedure. The results showed that this approach could encapsulate >80% of both QU and LU. Moreover, Fourier transform infrared (FTIR), differential scanning calorimetry (DSC), and powder X-ray diffraction (PXRD) spectra indicated that most of the QU and LU were trapped in a lipid matrix and dispersed homogeneously at the molecular level, increasing the solubility. Additionally, SLN-hydrogel composites are able to release two lipophilic bioactive compounds for 24 h, which also demonstrated increased skin retention and penetrability of the QU and LU up to 19-fold. In vitro blood biocompatibility showed that no hemolytic toxicity was observed below 500 μg/mL. Accordingly, the formulation was considered safe for use. Sun protective factor (SPF) test shows a value above 15, showing an excellent promising application as the photoprotective agent to prevent symptoms associated with photoinduced skin aging.

Glucomannan (GM)—a polysaccharide generally extracted from the tuber of Amorphophallus konjac—has great potential as a filler–binder in direct compression, disintegrant in tablets, or gelling agent due to its strong hydrophilicity and extremely high viscosity. However, it has poor water resistance and low mechanical strength when used as an excipient in solid form. Several physical and chemical modifications have been carried out to improve these drawbacks. Chemical modification affects the characteristics of GM based on the DS. Carboxymethylation improves GM functionality by modifying its solubility and viscosity, which in turn allows it to bind water more efficiently and thus improve its elongation and gel homogeneity. Meanwhile, physical modification enhances functionality through combination with other excipients to improve mechanical properties and modify swelling ability and drug release from the matrix. This review discusses extraction of GM and its modification to enhance its applicability as an excipient in solid form. Modified GM is a novel excipient applicable in the pharmaceutical industry for direct compression, as a tablet disintegrant, a film-forming agent, and for encapsulation of macromolecular compounds or drug carriers for controlled release.

The physicochemical properties of κ-carrageenan gels and their ester forms derived from different fatty-acid saturations were characterized and compared with those of native κ-carrageenan. Furthermore, stearic and oleic acids were used as the saturated and unsaturated fatty acids, respectively. Fourier-transform infrared (FTIR) spectra confirmed the introduction of the ester into the κ-carrageenan backbone. The thermogravimetric analysis showed that thermal stability increased along with the level of unsaturation, but there was a decrease in viscosity, hardness, and syneresis, which caused the consistency of the product to become more elastic. The results also showed that the ester form still has a swelling ability that is almost the same as that of κ-carrageenan. After being formulated into a gel dosage form, the product was successfully produced from the ester with unsaturated fatty acids, and it was more elastic than native κ-carrageenan and had good physical properties with spreadability that meets the requirements for topical preparations.