Preparation and characterization of semi-solid phospholipid dispersions and dilutions thereof

Brandl, Martin; Drechsler, Markus; Bachmann, Dieter; Tardi, Christine; Schmidtgen, Margret; Bauer, Karl-Heinrich

doi:10.1016/s0378-5173(98)00146-x

Cited by 42 publications

(20 citation statements)

References 16 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…This was surprising since the excellent reproducibility of the PCS results for the unfractionated material, along with a small figure for Chi-squared (0.47 ± 0.41) and a high number of data that were collected in channel number 1 as the basis for the autocorrelation function (1591.1 ± 67.3 k), seemed to indicate a well-founded result. Further results of particle size analyses of diluted VPGs prepared in the same manner and of comparable lipids from earlier studies [16] seem to confirm this observation. When analyzed by negative staining electron microscopy (NS-EM) vesicle sizes ranging to more than 95% below 50 nm had been found, which compares well with the PCS results upon fractionation here.…”

Section: Discussionsupporting

confidence: 76%

See 1 more Smart Citation

Determination of the size distribution of liposomes by SEC fractionation, and PCS analysis and enzymatic assay of lipid content

Ingebrigtsen

Brandl

2002

AAPS PharmSciTech

Self Cite

View full text Add to dashboard Cite

Section: Discussionsupporting

confidence: 76%

“…To achieve "classical" liposome dispersion, VPGs were diluted with excess buffer by mechanical agitation as first described by Brandl et al [16]. For a detailed protocol see Brandl and Massing [15].…”

Section: Vesicle Preparationmentioning

confidence: 99%

Determination of the size distribution of liposomes by SEC fractionation, and PCS analysis and enzymatic assay of lipid content

Ingebrigtsen

Brandl

2002

AAPS PharmSciTech

Self Cite

View full text Add to dashboard Cite

“…VPG-derived liposome formulations contain high lipid content contributing to a considerably increased ratio of aqueous volume inside the vesicles to the surrounding aqueous volume and thus are suitable for entrapping water-soluble substances with high EE (.50%). 29 In addition, use of formulations with high EE has the benefit that there is no need to remove the unencapsulated drug before use, making the production process more efficient. [30][31][32] In order to investigate the effect of SPC content on the EE of VPG liposomes for SBS, a series of liposome dispersions were prepared with increasing SPC/VPG from 250 to 500 mg/g.…”

Section: Results and Discussion Preparation Of Sbs Vpg And Sbs Dir Vpgmentioning

confidence: 99%

Liposomes prolong the therapeutic effect of anti-asthmatic medication via pulmonary delivery

Chen¹,

Huang²,

Wong³

et al. 2012

IJN

View full text Add to dashboard Cite

Purpose:The main objective of this study was to develop a novel aerosolized liposome formulation for pulmonary delivery of anti-asthmatic medication and to explore the relationship between the bioavailability and anti-asthmatic efficacy of such a formulation. Asthma treatment usually requires frequent administration of medication for sustained bronchodilating response. Liposomes are known for their capability for sustained drug release and thus would be a suitable delivery system for anti-asthmatic medication for prolonged therapeutic effect. Salbutamol sulfate (SBS) was chosen as the model drug in this study because of its high water solubility and fast absorption after administration. Methods: SBS was efficiently encapsulated into liposomes by the vesicular phospholipid gel technique. SBS permeability across the pulmonary membrane of an Asian toad was determined by in vitro study. Intratracheal administration of liposomes labeled with the fluorescent dye 1,1′-dioctadecyltetramethyl indotricarbocyanine iodide (DiR) in a rat model was assessed by a small animal imaging system and pharmacokinetic analysis. Pharmacodynamic analysis was performed in guinea pigs using the Konzett-Rössler method. Results: SBS was efficiently encapsulated into liposomes with encapsulation efficiency as high as 70%. The particle size of the SBS liposome suspension was approximately 57 ± 21 nm. In the in vitro study of permeability across the pulmonary membrane of Asian toads, SBS from liposomes demonstrated a slower transport rate compared to free SBS solution. Pulmonary delivery of liposomes in a rat model showed that the liposomes were effectively distributed in the respiratory tract and lungs, and that the release of SBS from liposomes was sustained for at least 48 hours. Pharmacodynamic analysis in a guinea pig model showed that the anti-asthmatic effect of SBS liposomes persisted for up to 18 hours, whereas that of free SBS solution was less than 8 hours. Conclusion:The overall results demonstrated that liposomes could increase the concentration and retention time of SBS in the lungs and therefore prolong its therapeutic effect.

show abstract

“…This may be due to the fact that the vesicles of liposomes might be close to maximum density sphere packing of the liposome preparation taken up by the vesicles when the content of SPC increased to 400 mg/g and the aqueous core of these vesicles might also approach the maximum of the total volume of all aqueous compartments. 13,14) Thus, there was only a slight increase in encapsulation efficiency when the content of SPC increased from 400 to 500 mg/g. Therefore, we selected the SPC concentration of 400 mg/g for the subsequent studies including the inhaler test.…”

Section: Selection Of Spc Concentration In Vpg Liposomesmentioning

confidence: 99%

Development of Liposomal Salbutamol Sulfate Dry Powder Inhaler Formulation

Huang

Yang

et al. 2010

Biological & Pharmaceutical Bulletin

View full text Add to dashboard Cite

The purpose of our study was to develop a formulation of liposomal salbutamol sulfate (SBS) dry powder inhaler (DPI) for the treatment of asthma. Liposomes of high encapsulation efficiency (more than 80%) were prepared by a vesicular phospholipid gel (VPG) technique. SBS VPG liposomes were subjected to lyophilization using different kinds of cryoprotectants in various mass ratios. Coarse lactose (63-106 m mm) in different mass ratios was used as a carrier. Magnesium stearate (0.5%) was added as a lubricator. The dry liposomal powders were then crushed by ball milling and sieved through a 400-mesh sieve to control the mean particle size at about 10 m mm. The effects of different kinds of cryoprotectants and the amount of lactose carrier on the fine particle fraction (FPF) of SBS were investigated. The results showed that the developed formulation of liposomal dry powder inhaler was obtained using lactose as a cryoprotectant with a mass ratio of lyophilized powder to carrier lactose at 1 : 5; 0.5% magnesium stearate was used as a lubricator. The value of FPF for SBS was 41.51؎ ؎2.22% for this formulation. Sustained release of SBS from the VPG liposomes was found in the in vitro release study. The study results offer the promising possibility of localized pulmonary liposomal SBS delivery in the anhydrous state.

show abstract

Preparation and characterization of semi-solid phospholipid dispersions and dilutions thereof

Cited by 42 publications

References 16 publications

Determination of the size distribution of liposomes by SEC fractionation, and PCS analysis and enzymatic assay of lipid content

Determination of the size distribution of liposomes by SEC fractionation, and PCS analysis and enzymatic assay of lipid content

Liposomes prolong the therapeutic effect of anti-asthmatic medication via pulmonary delivery

Development of Liposomal Salbutamol Sulfate Dry Powder Inhaler Formulation

Contact Info

Product

Resources

About