tretinoin and stearylamine

The aim of the present study was to reduce 5-FU side effects by targeted nanostructured lipid carriers (NLCs) to LDL receptors that are over expressed in colorectal carcinoma and also use of a new synthesized conjugate of retinoic acid as a cytotoxic agent. Fatty acyl amide derivative of retinoic acid was synthesized by its conjugation to octadecylamine with the expectation to improve its loading capacity in NLCs of 5-FU. The NLCs were prepared by an emulsification-solvent evaporation method using cholesterol and cholesteryl stearate. Physical properties and drug release were studied in NLCs. The cytotoxicity of NLCs loaded with 5-FU and retinoic acid conjugate was studied on colon cancer cells (HT29) using MTT assay. To confirm that drug targeting has been done through LDL receptors, APO-E was omitted from the cell culture and the MTT assay was repeated. FTIR and (1)H NMR spectra confirmed successful production of the conjugate. Results showed the IC(50) of free 5-FU was about 7.6 μM while in comparable concentration, the cytotoxicity of 5-FU loaded in NLCs containing the retinoic acid conjugate was nearly 2 fold of NLCs just loaded with 5-FU and more than 5 fold of free 5-FU. The retinoic acid conjugate loaded NLCs prepared by cholesterol can target LDL receptors of HT29 cells and seems promising in reducing 5-FU dose in colorectal cancer.

Topics: Amines; Antineoplastic Agents; Cell Proliferation; Cell Survival; Chemistry Techniques, Synthetic; Cholesterol; Drug Carriers; Fluorouracil; HT29 Cells; Humans; Nanostructures; Receptors, LDL; Structure-Activity Relationship; Tretinoin

This work aims to investigate the influence of the formation of ion pairing between all-trans retinoic acid (RA) and a lipophilic amine (stearylamine; STE) on the drug encapsulation efficiency (EE) and stability of solid lipid nanoparticles (SLNs). The SLNs were characterized for EE and size. The EE and particle size were significantly improved and reduced, respectively, when the surfactant or co-surfactant concentration increased. However, while the formulation without STE allowed only 13% of RA encapsulation, the EE for RA-STE-loaded SLNs was 94%. The stability studies showed a significant decrease in EE for the SLNs without STE, while, for SLNs loaded with RA and STE, the EE remained constant after 360 days. The interactions among ion pairing components and the lipid matrix were investigated through small-angle X-ray scattering (SAXS). The SAXS analysis revealed the presence of RA in the crystalline form in SLNs without ion pairing, while crystalline RA was not observed in SLNs loaded with RA/amine. Skin irritation studies showed that the SLNs loaded with the ion pairing were significantly less irritating when compared to the marketed RA-cream. This novel SLN formulation represents a promising alternative for topical treatment of acne with RA.

Topics: Acne Vulgaris; Administration, Cutaneous; Amines; Animals; Chemistry, Pharmaceutical; Drug Delivery Systems; Drug Stability; Electrochemical Techniques; Emulsions; Exanthema; Excipients; Female; Mice; Mice, Hairless; Nanoparticles; Particle Size; Phase Transition; Scattering, Small Angle; Surface Properties; Surface-Active Agents; Tretinoin; X-Ray Diffraction

Because of their antiproliferative and differentiation-inducing properties, retinoids have been used clinically as therapeutic and chemopreventive agents against squamous-cell carcinomas (SCC). As is the case for many therapeutic agents, however, the administration of retinoids is associated with toxic effects. Because encapsulation of certain drugs in lipid vesicles (liposomes) has been shown to result in reduced toxic effects, we studied the in vitro interaction of liposome-encapsulated all-trans-retinoic acid (L-ATRA) with a SCC line (MDA 886Ln) and its multicellular tumor spheroid (MTS) model. Various L-ATRA formulations were tested for incorporation of retinoic acid, toxic effects against human red blood cells, uptake and retention by tumor cells, and antiproliferative effects against SCC. Of the different formulations tested, L-ATRA containing diphosphatidyl palmitoylcholine (DPPC) and stearylamine (SA; 9:1, w/w) showed optimal drug incorporation, high stability, and minimal toxicity toward red blood cells and was highly efficacious in delivering ATRA and, thus, in inhibiting the growth of MDA 886Ln and its MTS model. DPPC: SA L-ATRA inhibited the expression of the enzyme keratinocyte transglutaminase in epidermal cells as effectively as did the free drug. These results suggest that liposomes can serve as an effective carrier system for the delivery of retinoids to SCC.

Topics: 1,2-Dipalmitoylphosphatidylcholine; Amines; Carcinoma, Squamous Cell; Cell Division; Erythrocytes; Humans; Liposomes; Middle Aged; Transglutaminases; Tretinoin; Tumor Cells, Cultured