Pharmaceutical Research

, Volume 27, Issue 9, pp 1977–1986

Inhalable Microparticles as Carriers for Pulmonary Delivery of Thymopentin-Loaded Solid Lipid Nanoparticles

Research Paper

ABSTRACT

Purpose

Microparticles containing solid lipid nanoparticles (SLNs) are receiving increased attention as carriers for the lung delivery of the SLNs. Thus, we aim to prepare the hybrid microparticles and thoroughly evaluate their feasibility for the pulmonary drug delivery.

Methods

The microparticles were prepared by co-spray-drying the thymopentin (TP5)-loaded SLNs with bulking agents. Thereafter, we systematically estimated the potential of the microparticles as the carriers for the pulmonary delivery of the SLNs, including the investigations of their characteristics, aerodynamic properties, pharmacokinetics and pharmacodynamics.

Results

The spherical and hollow microparticles presented a size of 4.1 ± 0.1 μm and a low tap density of 0.175 ± 0.02 g/cm3. In addition, the microparticles showed a high aerosolization efficiency (emitted dose of 98.0% ± 1.23% and respirable fraction of 51.07% ± 1.21%). Furthermore, the SLNs could be easily recovered from the microparticles without essential changes on their characteristics and the drug release behavior. The pharmacokinetic and pharmacodynamic studies suggested that, compared to i.v. TP5 solution, the bioavailability and therapeutic efficacy of TP5 were remarkably strengthened after the pulmonary administration of the microparticles.

Conclusions

Taken together, we believe the microparticles were suitable for inhalation and possesed an ample potential for the pulmonary delivery of the SLNs.

KEY WORDS

pulmonary delivery microparticles solid lipid nanoparticles spray-drying thymopentin 

ABBREVIATIONS

AUC

area under the curve

CLSM

confocal laser scanning microscope

ED

emitted dose

EE%

encapsulation efficacy

DPI

dry powder inhaler

FITC

fluorescein isothiocyanate

HPLC

high performance liquid chromatography

i.v.

intravenous injection

mAb

monoclonal Antibodies

MRT

mean residence time

PBS

phosphate buffer

PDI

polydispersity index

RD

respirable dose

RF

respirable fraction

SD

standard deviation

SEM

scanning electron microscopy

SLNs

solid lipid nanoparticles

SOD

superoxide dismutase

TP5

thymopentin

TSI

twin stage impinger

W/O

water in oil

W/O/W

water in oil in water

Copyright information

© Springer Science+Business Media, LLC 2010

Authors and Affiliations

  1. 1.Key Laboratory of Drug Targeting and Novel Drug Delivery Systems West China School of PharmacySichuan UniversityChengduPeople’s Republic of China

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