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AOCS Phospholipid Division
Newsletter April 2008

Various Lecithin Papers

Dermal delivery of selected hydrophilic drugs from elastic liposomes: effect of phospholipid formulation and surfactants; Ita, K.B.; Du Preez, J.; Lane, M..E.; Hadgraft, J.; du Plessis, J.; Journal of Pharmacy and Pharmacology 59:1215-1222 (2007).  

The effect of phospholipid formulation and choice of surfactant on skin permeation of selected hydrophilic drugs from elastic liposomes across human epidermal membrane has been studied. Sodium cholate and various concentrations of phosphatidylcholine were used for the preparation of liposomes namely hydrogenated phosphatidylcholine 90% (Phospholipon 90H), phosphatidylcholine 95% (Phospholipon 90G), phosphatidylcholine 78.6% (Phospholipon 80), and phosphatidylcholine 50% (Phosal PG). To investigate the effect of the surfactant, liposomes were prepared from 95% phosphatidylcholine (Phospholipon 90G) and various surfactants (sodium cholate, sodium deoxycholate, Span 20 (sorbitan monolaurate), Span 40 (sorbitan monopalmitate), Span 60 (sorbitan stearate) and Span 80 (sorbitan monooleate)). The vesicles were prepared by the conventional rotary evaporation technique. The film was hydrated with phosphate-buffered saline (10 mL) containing 9, 2 and 2.5 mg mL^-1 of methotrexate, idoxuridine and aciclovir, respectively. All formulations contained 7% ethanol. Homogenously-sized liposomes were produced following extrusion through 100-nm polycarbonate filters using Lipex Extruder. Particle size was characterized by transmission electron microscopy. Vertical Franz diffusion cells were used for the study of drug delivery through human epidermal membrane. For the three drugs, the highest transcutaneous fluxes were from elastic liposomes containing 95% phosphatidylcholine. In general, a higher flux value was obtained for liposomes containing sodium cholate compared with sodium deoxycholate. For the liposomes containing sorbitan monoesters, there was no clearly defined trend between alkyl chain length and flux values. Overall, transcutaneous fluxes of liposomal preparations of hydrophilic drugs were comparable with those from saturated aqueous solutions (P > 0.05).

Sorbitan monolaurate; Sorbitan monopalmitate; Sorbitan monostearate; Sorbitan monooleate; Lecithin; Acyclovir   

Curative effect of soybean lecithin on cerebral infarction; Shi, F; Zhou, J; Meng, D, (journal) Zhonghua Yi Xue Za Zhi 81:1301-1303 (2001).

OBJECTIVE: To investigate the clinical curative effect of soybean lecithin on cerebral infarction. METHODS: 542 patients with cerebral infarction within 48 h after the onset with the nervous function defect scores of 31-35 were divided into 3 groups: basic treatment group, 60 cases, with conventional treatment; citicoline group, 122 patients, with conventional treatment and citicoline; and soybean lecithin group, 360 patients, with conventional treatment and soybean lecithin 10 g tid. For all patients, treatment began sometime within 48 hours after the onset. The treatment course lasted 28 days. RESULTS: When the course was over, the infarct volumes in basic group citicoline group, and soybean lecithin group, were 7.6 cm³ ± 2.9 cm³, 7.3 cm³ ± 3.1 cm³, and 6.4 cm³ ± 2.7 cm³, respectively (F = 7.371, P = 0.0007). The basic group and citicoline group being compared with the soybean group by Dunnett test, t = 4.387 and 3.969 respectively, P < 0.01. The nervous function defect integral in the three groups decreased 14.2 ± 10.93, 15.0 ± 9.0, and 18.5 ±10.9, respectively. Two-way analysis of variance of drug kind and beginning time of treatment showed the value of F in drugs as 6.250, P = 0.0021, and value of F in times as 0.9417, P = 0.4201. In the order of death, deterioration, nonimprovement, improvement, significant improvement, and recovery, the ridit values for the comprehensive curative effect in the 3 groups were 0.4003, 0.4118, and 0.54 5 respectively; χ² = 27.89, P < 0.001. CONCLUSION: Soybean lecithin is effective in treatment of acute cerebral infarction. The mechanism may be that soybean lecithin lowers the decrease of brain phospholipid content in brain ischemia.

Study of liposomes stability containing soy phosphatidyletholine and hydrogenated soy phosphatidylcholine adding or not cholesterol by turbidity method; Chorilli, M.; de Rimerio, T.C.; Oliveira, A.G.; Scarpa, M.V., Latin American Journal of Pharmacy 26: 31 - 37 (2007).   

Liposomes are structures composed by phospholipids as soy phosphatidylcholine (PC) and hydrogenated soy phosphatidylcholine (PCH). Among the methods used to prove liposomes' stability, turbidity method is widely used. The objective of this work was to study the stability of liposomes containing PC or PCH with and without cholesterol (CHOL) by turbidity method. Liposomes were stored a 30°C during 90 days and periodically absorbance readings at 410 nm were made to verify possible turbidity alterations. Increases in the turbidity with time occurred for PC liposomes. In the presence of CHOL higher turbidity was obtained probably reflecting the increase in the size of liposomes. For PCH liposomes the presence of CHOL did not affect the turbidity suggesting higher physical stability of the structures.

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Also in this newsletter:

Greetings from the Chair, by Jonathan Maynes

Hermann Pardun Prize

Short Course: Lecithin & Phospholipids in Emulsions

Flanders' Food Emulsion Seminars in Spring 2008

AOCS, 2710 S. Boulder, Urbana, IL 61802-6996 USA