3 research outputs found
Controlled Dissolution of Griseofulvin Solid Dispersions from Electrosprayed Enteric Polymer Micromatrix Particles: Physicochemical Characterization and <i>in Vitro</i> Evaluation
The oral bioavailability
of a poorly water-soluble
drug is often inadequate for the desired therapeutic effect. The bioavailability
can be improved by enhancing the physicochemical properties
of the drug (e.g., dissolution rate, permeation across the gastrointestinal
tract). Other approach include shielding the drug from the gastric
metabolism and targeted drug release to obtain optimal drug absorption.
In this study, a poorly water-soluble model drug, griseofulvin,
was encapsulated as disordered solid dispersions into Eudragit L 100-55
enteric polymer micromatrix particles, which were produced by
electrospraying. Similar micromatrix particles were also
produced with griseofulvin-loaded thermally oxidized mesoporous
silicon (TOPSi) nanoparticles dispersed to the polymer micromatrices.
The <i>in vitro</i> drug dissolution at pH 1.2 and 6.8,
and permeation at pH 7.4 across Caco-2/HT29 cell monolayers from the
micromatrix particles, were investigated. The micromatrix
particles were found to be gastro-resistant, while at pH 6.8 the griseofulvin
was released very rapidly in a fast-dissolving form. Compared to free
griseofulvin, the permeability of encapsulated griseofulvin
across the intestinal cell monolayers was greatly improved, particularly
for the TOPSi-doped micromatrix particles. The griseofulvin
solid dispersions were stable during storage for 6 months at accelerated
conditions. Overall, the method developed here could prove to be a
useful oral drug delivery solution for improving the bioavailability
of poorly water-soluble or otherwise problematic drugs
<i>In Vitro</i> and <i>Ex Vivo</i> Evaluation of Polymeric Nanoparticles for Vaginal and Rectal Delivery of the Anti-HIV Drug Dapivirine
Prevention
strategies such as the development of microbicides are
thought to be valuable in the fight against HIV/AIDS. Despite recent
achievements, there is still a long road ahead in the field, particularly
at the level of drug formulation. Drug nanocarriers based on polymers
may be useful in enhancing local drug delivery while limiting systemic
exposure. We prepared differently surface-engineered poly(ε-caprolactone)
(PCL) nanoparticles (NPs) and tested their ability to modulate the
permeability and retention of dapivirine in cell monolayers and pig
vaginal and rectal mucosa. NPs coated with poly(ethylene oxide) (PEO)
were shown able to reduce permeability across monolayers/tissues,
while modification of nanosystems with cetyl trimethylammonium bromide
(CTAB) enhanced transport. In the case of coating NPs with sodium
lauryl sulfate (SLS), dapivirine permeability was unchanged. All NPs
increased monolayer/tissue drug retention as compared to unformulated
dapivirine. This fact was associated, at least partially, to the ability
of NPs to be taken up by cells or penetrate mucosal tissue. Cell and
tissue toxicity was also affected differently by NPs: PEO modification
decreased the <i>in vitro</i> (but not <i>ex vivo</i>) toxicity of dapivirine, while higher toxicity was generally observed
for NPs coated with SLS or CTAB. Overall, presented results support
that PCL nanoparticles are capable of modulating drug permeability
and retention in cell monolayers and mucosal tissues relevant for
vaginal and rectal delivery of microbicides. In particular, PEO-modified
dapivirine-loaded PCL NPs may be advantageous in increasing drug residence
at epithelial cell lines/mucosal tissues, which may potentially increase
the efficacy of microbicide drugs
Microfluidic Assembly of a Multifunctional Tailorable Composite System Designed for Site Specific Combined Oral Delivery of Peptide Drugs
Multifunctional tailorable composite systems, specifically designed for oral dual-delivery of a peptide (glucagon-like peptide-1) and an enzymatic inhibitor (dipeptidyl peptidase 4 (DPP4)), were assembled through the microfluidics technique. Both drugs were coloaded into these systems for a synergistic therapeutic effect. The systems were composed of chitosan and cell-penetrating peptide modified poly(lactide-<i>co</i>-glycolide) and porous silicon nanoparticles as nanomatrices, further encapsulated in an enteric hydroxypropylmethylcellulose acetylsuccinate polymer. The developed multifunctional systems were pH-sensitive, inherited by the enteric polymer, enabling the release of the nanoparticles only in the simulated intestinal conditions. Moreover, the encapsulation into this polymer prevented the degradation of the nanoparticles’ modifications. These nanoparticles showed strong and higher interactions with the intestinal cells in comparison with the nonmodified ones. The presence of DPP4 inhibitor enhanced the peptide permeability across intestinal cell monolayers. Overall, this is a promising platform for simultaneously delivering two drugs from a single formulation. Through this approach peptides are expected to increase their bioavailability and efficiency <i>in vivo</i> both by their specific release at the intestinal level and also by the reduced enzymatic activity. The use of this platform, specifically in combination of the two antidiabetic drugs, has clinical potential for the therapy of type 2 diabetes mellitus