Liposomal pulmonary drug delivery I.<i>In vivo</i>disposition of atropine base in solution and liposomal form following endotracheal instillation to the rabbit lung

Meisner, Dale; Pringle, Joan; Mezei, Michael

doi:10.3109/02652048909019920

Cited by 31 publications

(9 citation statements)

References 9 publications

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“…This result extends those of a previous study in which short-term aerosolized liposome-incorporated corticosteroids did not reduce endogenous cortisol levels [ 171. As previously stated, the elimination of systemic absorption of drugs after local administration to the lung would be advantageous in decreasing undesirable side-effects associated with aerosol therapy [30].…”

Section: Discussionmentioning

confidence: 97%

Liposomal dexamethasone effectiveness in the treatment of hypersensitivity pneumonitis in mice

Tremblay

Thérien

Rocheleau

et al. 1993

Eur J Clin Investigation

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The effects of daily intranasal instillation of liposomal dexamethasone and free dexamethasone phosphate were compared in a murine model of hypersensitivity pneumonitis induced by Saccharopolyspora rectivirgula (formally known as Micropolyspora faeni). After 3 weeks of antigen and liposome instillations, lung response was evaluated by bronchoalveolar lavage cell counts, lung index and histopathology. Systemic absorption was evaluated by measuring plasma adrenocorticotropic hormone (ACTH) level. Free dexamethasone phosphate induced a dose-dependent response with the maximal effect reached at 1 mg kg-1. At 0.1 mg kg-1, liposomal dexamethasone had a greater effect than free dexamethasone phosphate on bronchoalveolar cells ml-1: 3.01 x 10(5) +/- 0.35 x 10(5) compared to 4.70 x 10(5) +/- 0.34 x 10(5), and lung index: 1.22 +/- 0.10 compared to 1.86 +/- 0.07. Effect on histopathology was similar. Plasma ACTH levels (pg ml-1) were: 75.1 +/- 14.0 for animals receiving antigen and free dexamethasone phosphate (0.2 mg kg-1), and 149.7 +/- 12.0 for animals receiving antigen and liposomal dexamethasone (0.2 mg kg-1). In conclusion, liposome-incorporated dexamethasone is efficient in the treatment of experimental hypersensitivity pneumonitis and, contrarily to free dexamethasone phosphate, does not inhibit ACTH secretion.

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Section: Discussionmentioning

confidence: 97%

Liposomal dexamethasone effectiveness in the treatment of hypersensitivity pneumonitis in mice

Tremblay

Thérien

Rocheleau

et al. 1993

Eur J Clin Investigation

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“…As shown in Figure 2a, proliposomes are typically hydrated and annealed using deionised water (DW). Following centrifugation for separation in DW, liposomes were found to sediment at the bottom of the centrifuge tube, allowing for their collection for analysis ( Figure 2b) (Meisner et al 1989;Taylor et al 1990;Ma et al 1991). When BDP is used in liposome formulations, DW as a dispersion medium may cause the unentrapped BDP crystals and liposomes (containing the entrapped drug) to sediment simultaneously upon centrifugation (Batavia et al 2001).…”

Section: 3separation Of Bdp-loaded Liposomes From Free Bdp Crystalsmentioning

confidence: 99%

Proliposome powders prepared using a slurry method for the generation of beclometasone dipropionate liposomes

Khan

Yousaf

Subramanian

et al. 2015

International Journal of Pharmaceutics

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A novel "slurry method" was described for the preparation of proliposome powders using soya phosphatidylcholine (SPC) with cholesterol (1:1) and for incorporation of beclometasone dipropionate (BDP) at 2mole% of the total lipid phase. Proliposomes made with a range of lipid to sucrose carrier ratios were studied in terms of surface morphology using scanning electron microscopy (SEM) and thermal properties using differential scanning calorimetry (DSC). Following hydration of proliposomes, the resultant vesicles were compared to liposomes made using the traditional proliposome method, in terms of vesicle size and drug entrapment efficiency. SEM showed that sucrose was uniformly coated with lipid regardless of lipid to carrier ratio. Liposomes generated using the slurry proliposome method tended to have smaller median size than those generated with the conventional proliposome method, being in the range of 4.72-5.20μm and 5.89-7.72μm respectively. Following centrifugation of liposomes using deuterium oxide (D2O) as dispersion medium, vesicles entrapping BDP were separated as a floating creamy layer, whilst the free drug was sedimented as crystals. Drug entrapment was dependent on formulation composition and preparation method. When 1:15 w/w lipid to carrier was used, liposomes generated using the slurry method had an entrapment efficiency of 47.05% compared to 18.67% for those generated using the conventional proliposome method. By contrast, liposomes made by the thin-film hydration method had an entrapment efficiency of 25.66%. DSC studies using 50mole% BDP demonstrated that the drug was amorphous in the proliposome formulation and tended to crystallize on hydration, resulting in low drug entrapment. In conclusion, a novel approach to the preparation of proliposomes using a slurry method has been introduced, offering higher entrapment for BDP than liposomes made using the conventional proliposome method and those prepared by thin-film hydration technique.

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“…[23][24][25] LTHC was prepared by entrapping ⌬9-THC in liposomes composed of dipalmitoylphosphatidylcholine and cholesterol (Avanti Polar Lipids; Alabaster, AL) in a 7:3 molar ratio. Briefly, the lipids were dissolved in a minimal volume of chloroform in a round-bottomed glass vessel, followed by the addition of a defined amount of ⌬9-THC (Sigma-Aldrich Canada, Ltd.; Oakville, Ontario, Canada).…”

Section: Drug Preparation and Administrationmentioning

confidence: 99%

Ocular Hypotensive Effects of an Intratracheally Delivered Liposomal Δ9-Tetrahydrocannabinol Preparation in Rats

Szczesniak

Kelly²,

Whynot³

et al. 2006

Journal of Ocular Pharmacology and Therapeutics

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This study investigated the effect of an intratracheal (i.t.) administration of a liposome-entrapped Delta9-tetrahydrocannabinol (LTHC) preparation on intraocular pressure (IOP) in nonanaesthetized Brown Norway rats. The ocular hypotensive effects of i.t. LTHC were compared to that of intraperitoneal (i.p.) LTHC administration. All i.t. LTHC doses >0.05 mg/kg significantly decreased IOP (P < 0.05) within 30 min of administration, and doses of i.t. LTHC >0.1 mg/kg decreased IOP within 15 min of administration. A maximal reduction in IOP of 2.32 +/- 0.27 mmHg (n = 4) was seen with 1.0 mg/kg of i.t. LTHC. In comparison, no significant IOP drop was apparent prior to 30 min with all doses (0.01-1.0 mg/kg) of i.p. LTHC tested, although a similar maximum drop in IOP (2.15 +/- 0.12 mmHg; n = 8) was obtained with 1.0 mg/kg of LTHC. The ED(50) for i.t. and i.p. LTHC was 0.08 mg/kg and 0.12 mg/kg, respectively. The IOP-lowering effects of i.p. LTHC (0.2 mg/kg) were reduced by 14% and 80% by 0.25 mg/kg (n = 6) and 2.5 mg/kg (n = 6), respectively, of the CB1R antagonist, SR141716A. In conclusion, i.t. LTHC was superior to i.p. LTHC in producing a more rapid and potent decrease in IOP. The IOP-lowering effect of LTHC was blocked by the CB1R-selective antagonist, SR141716A, suggesting that CB1Rs contribute to the ocular hypotensive effect of Delta9-tetrahydrocannabinol.

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Liposomal pulmonary drug delivery I.In vivodisposition of atropine base in solution and liposomal form following endotracheal instillation to the rabbit lung

Cited by 31 publications

References 9 publications

Liposomal dexamethasone effectiveness in the treatment of hypersensitivity pneumonitis in mice

Liposomal dexamethasone effectiveness in the treatment of hypersensitivity pneumonitis in mice

Proliposome powders prepared using a slurry method for the generation of beclometasone dipropionate liposomes

Ocular Hypotensive Effects of an Intratracheally Delivered Liposomal Δ9-Tetrahydrocannabinol Preparation in Rats

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