title: Injectable nimodipine-loaded nanoliposomes: preparation, lyophilization and characteristics.
abstract: The main purpose of this study was to prepare nimodipine-loaded nanoliposomes for injection and evaluate their characteristics after lyophilization. Nimodipine-loaded nanoliposomes were prepared by the emulsion-ultrasonic method with sodium cholesterol sulfate (SCS) as the regulator and then lyophilized by adding different cryoprotectants. SCS was used as a blender of regulator and surfactant and helped to prepare smaller liposomes due to the steric hindrance of the sulfate group. The results showed that nimodipine-loaded nanoliposomes with a 20:1 of egg yolk lecithin PL-100M vs. SCS ratio had a particle size of 86.8±42.007 nm, a zeta potential of -13.94 mV and an entrapment efficiency (EE) of 94.34% and could be stored for 12 days at 25°C. Because of the good bulking effect of mannitol and the preservative effect of trehalose, they were used to obtain suitable lyophilized nanoliposomes. The lyophiles containing 10% mannitol and 20% trehalose had a good appearance and a slightly altered particle size after rehydration. In addition, the lyophilized products were characterized by differential scanning calorimetry, X-ray diffraction and scanning electron microscopy, which confirmed the morphous state of trehalose, mannitol and the mixture. Trehalose could inhibit mannitol crystallization to some extent. The drug release from nanoliposomes before and after lyophilization in pH 7.4 phosphate buffer containing 30% ethanol was also examined and both profiles were found to fit the Viswanathan equation. This means that the drug release was controlled by the pore diffusion resistance.
authors.affiliation: Department of Pharmaceutics, Shenyang Pharmaceutical University, Wen Hua Road No. 103, Liaoning, Shenyang 110016, China.
authors.forename: Tingting
authors.initials: T
authors.lastname: Guan
authors.forename: Yuqiang
authors.initials: Y
authors.lastname: Miao
authors.forename: Lishuang
authors.initials: L
authors.lastname: Xu
authors.forename: Shenshen
authors.initials: S
authors.lastname: Yang
authors.forename: Jing
authors.initials: J
authors.lastname: Wang
authors.forename: Haibing
authors.initials: H
authors.lastname: He
authors.forename: Xing
authors.initials: X
authors.lastname: Tang
authors.forename: Cuifang
authors.initials: C
authors.lastname: Cai
authors.forename: Hui
authors.initials: H
authors.lastname: Xu
mesh_terms: D002121:Calcium Channel Blockers / Q000008:administration & dosage* / Q000737:chemistry; D002152:Calorimetry, Differential Scanning; D002788:Cholesterol Esters / Q000737:chemistry; D003451:Cryoprotective Agents / Q000737:chemistry; D004356:Drug Storage; D004655:Emulsions; D005079:Excipients / Q000737:chemistry*; D005612:Freeze Drying; D008081:Liposomes; D008353:Mannitol / Q000737:chemistry; D008855:Microscopy, Electron, Scanning; D053758:Nanoparticles; D009553:Nimodipine / Q000008:administration & dosage* / Q000737:chemistry; D010316:Particle Size; D013501:Surface-Active Agents / Q000737:chemistry; D014199:Trehalose / Q000737:chemistry; D014961:X-Ray Diffraction
chemical_list: D002121:Calcium Channel Blockers; D002788:Cholesterol Esters; D003451:Cryoprotective Agents; D004655:Emulsions; D005079:Excipients; D008081:Liposomes; D013501:Surface-Active Agents; D008353:Mannitol; D009553:Nimodipine; D014199:Trehalose; C007045:cholesteryl sulfate