Melting point depression of solid lipids in pressurized carbon dioxide

Melting Point Depression of Poly(ethylene oxide)-Poly(propylene oxide)-Poly(ethylene oxide) Triblock Polymers in Supercritical Carbon Dioxide in the Presence of Menthol as a Solid Co-Plasticiser

The melting behaviour of the triblock polymers, Pluronic F38, F68, F77, F108, and F127, was investigated in pressurised CO₂ and in the presence of menthol. The melting points of the polymers combined with 0, 10, 25, and 50 wt% of menthol were studied at atmospheric pressure and compared with those at 10 and 20 MPa in supercritical carbon dioxide (scCO₂). The highest melting point depressions of 16.8 ± 0.5 °C and 29.0 ± 0.3 °C were observed at 10 and 20 MPa, respectively. The melting point of triblock polymers in pressurised CO₂ was found to be dependent on molecular weight, poly(propylene oxide) (PPO) content, and menthol percentage. The melting point of most of the polymers studied in this work can be reduced to room temperature, which can be pivotal to the formulation development of thermolabile substances using these polymers.

Progress in nanostructure understanding of edible crystalline fats and their application in nano-delivery systems: Cocoa butter as a model

Nucleation and crystal growth of edible fats at the nanoscale have received little attention due to analytical limitations. A key factor to modify the properties of edible fats is nanostructure understanding. Progress within the last years will be presented, including analytical techniques used to investigate fat crystallization. Cocoa butter has been the subject of several works due to its properties and its high impact on chocolate manufacturing. Moreover, this vegetable fat has been used as the solid lipid component in nano delivery systems. Since nanoplatelet is the smallest unit in crystalline fats, and the nanoscale is influenced by supersaturation, temperature, shear fields, and surfactants, nanostructure engineering is possible. On its part, cocoa butter has been included in innovative delivery systems along the last years. This review will highlight main results and challenges on these topics.

In vitro bioaccessibility of fish oil-loaded hollow solid lipid micro- and nanoparticles

Fish oil-loaded hollow solid lipid micro- and nanoparticles were prepared by atomization of the CO2-expanded lipid mixture. The obtained particles were spherical and free-flowing with an average particle size of 6.9 μm. Fish oil loading efficiency was achieved at 92.3% (w/w). The in vitro digestive stability, lipid digestibility and EPA and DHA bioaccessibility of the fish oil-loaded particles were examined using an in vitro sequential digestion model. The mean particle diameter increased markedly after oral (15.2 μm) and gastric (32.4 μm) digestion and then decreased after the small intestinal stage (24.0 μm). Fish oil-loaded particles remained spherical and intact but mainly agglomerated on the top phase throughout the oral and gastric digestion. However, a mixed digesta was formed after the small intestinal digestion, which contained digested broken particle pieces, undigested fish oil-loaded particles, free fatty acids, monoacylglycerols and micelles. The extent of lipolysis was significantly increased for the 30% fish oil-loaded particles as compared to physical mixtures of empty hollow solid lipid particles or bulk FHSO and fish oil (p < 0.05). Moreover, EPA and DHA bioaccessibility was significantly improved from 9.7 to 18.2% with the 30% fish oil-loaded particles (p < 0.05).

Skin permeation, biocompatibility and antitumor effect of chloroaluminum phthalocyanine associated to oleic acid in lipid nanoparticles

The objective of this study was to develop and characterize lipid nanoparticles (LNs) containing chloroaluminum phthalocyanine (ClAlPc) to reduce the aggregation of the drug and improve its skin penetration and its antitumor effect. LNs were prepared and characterized by using stearic acid (SA) as solid lipid and oleic acid (OA) as liquid lipid in different proportions. in vitro and in vivo skin penetration was evaluated using modified Franz diffusion cells and fluorescence microscopy, respectively. in vitro biocompatibility and Photodynamic Therapy (PDT) were performed using L929-fibroblasts cell line and A549 cancer cell line and melanoma BF16-F10, respectively. OA promoted the increase in the encapsulation efficiency and drug loading, reaching values of 95.8% and 4%, respectively. The formulation with 40% OA (NLC 40) showed a significantly higher (p < 0.01) amount of drug retained in the skin compared to other formulations. All formulations developed were considered biocompatible. PDT evidenced the antitumor efficacy of NLC 40 with reduced cell viability for approximately 10% of cancer cells, demonstrating that the presence of OA in the NLC seems to potentialize this antitumor effect. PDT in BF16-F10 melanoma using NLC 40 resulted in a reduction in mean cell viability of approximately 99%. According to the results obtained, the systems developed may be promising for the incorporation of ClAlPc in the treatment of skin cancer by photodynamic therapy.

Solid dispersions of efonidipine hydrochloride ethanolate with improved physicochemical and pharmacokinetic properties prepared with microwave treatment

Drug absorption into the body is known to be greatly affected by the solubility of the drug itself. The active pharmaceutical ingredient efonidipine hydrochloride ethanolate (NZ-105) is a novel 1,4-dihydropyridine calcium antagonist that has a very low solubility in water. It is classified as a poorly soluble drug, and improvements in its solubility and higher bioavailability with oral administration are needed. In this study, employing microwave technology as a new means to improve solubility, we established a method for preparing solid dispersions using hydroxypropyl methylcellulose acetate succinate as a polymeric carrier and urea as a third component. This effective method has a treatment time of several minutes (simple) and does not require the use of organic solvents (low environmental impact). The third component, urea, acts to lower the melting point of NZ-105, which promotes amorphization. This greatly improves the solubility compared with the microwave-treated product of NZ-105/HPMC-AS binary system. The solid dispersion prepared with this method, in addition to evaluation in vitro, was tested in vivo using beagle dogs and shown to be effective from the eightfold improvement in absorption compared with NZ-105 alone based on the area under the curve.