2 research outputs found
Fabrication and Characterization of Clozapine Nanoemulsion SolāGel for Intranasal Administration
Clozapine is the most effective antipsychotic
for treatment-resistant
schizophrenia. However, it causes many adverse drug reactions (ADRs),
which lead to poor treatment outcomes. Nose-to-brain (N2B) drug delivery
offers a promising approach to reduce peripheral ADRs by minimizing
systemic drug exposure. The aim of the present study was to develop
and characterize clozapine-loaded nanoemulsion solāgel (CLZ-NESG)
for intranasal administration using high energy sonication method.
A range of oils, surfactants, and cosurfactants were screened with
the highest clozapine solubility selected for the development of nanoemulsion.
Pseudoternary phase diagrams were constructed using a low-energy (spontaneous)
method to identify the microemulsion regions (i.e., where mixtures
were transparent). The final formulation, CLZ-NESG (pH 5.5 Ā±
0.2), comprising 1% w/w clozapine,
1% w/w oleic acid, 10% w/w polysorbate 80/propylene glycol (3:1), and 20% w/w poloxamer 407 (P407) solution, had
an average globule size of ā¤30 nm with PDI 0.2 and zeta potential
of ā39.7 Ā± 1.5 mV. The in vitro cumulative
drug release of clozapine from the nanoemulsion gel at 34 Ā°C
(temperature of nasal cavity) after 72 h was 38.9 Ā± 4.6% compared
to 84.2 Ā± 3.9% with the control solution. The permeation study
using sheep nasal mucosa as diffusion barriers confirmed a sustained
release of clozapine with 56.2 Ā± 2.3% cumulative drug permeated
after 8 h. Additionally, the histopathological examination found no
severe nasal ciliotoxicity on the mucosal tissues. The thermodynamic
stability studies showed that the gel strength and viscosity of CLZ-NESG
decreased after temperature cycling but was still seen to be in āgelā
form at nasal temperature. However, the accelerated storage stability
study showed a decrease in drug concentration after 3 months, which
can be expected at elevated stress conditions. The formulation developed
in this study showed desirable physicochemical properties for intranasal
administration, highlighting the potential value of a nanoemulsion
gel for improving drug bioavailability of clozapine for N2B delivery
Solvent sensitivity of protein aggregation in Cu, Zn superoxide dismutase: a molecular dynamics simulation study
<p>Misfolding and aggregation of Cu, Zn Superoxide Dismutase (SOD1) is often found in amyotrophic lateral sclerosis (ALS) patients. The central apo SOD1 barrel was involved in protein maturation and pathological aggregation in ALS. In this work, we employed atomistic molecular dynamics (MD) simulations to study the conformational dynamics of SOD1<sup>barrel</sup> monomer in different concentrations of trifluoroethanol (TFE). We find concentration dependence unusual structural and dynamical features, characterized by the local unfolding of SOD1<sup>barrel</sup>. This partially unfolded structure is characterized by the exposure of hydrophobic core, is highly dynamic in nature, and is the precursor of aggregation seen in SOD1<sup>barrel</sup>. Our computational studies supports the hypothesis of the formation of aggregation ābuilding blocksā by means of local unfolding of apo monomer as the mechanism of SOD1 fibrillar aggregation. The non-monotonic TFE concentration dependence of protein conformational changes was explored through simulation studies. Our results suggest that altered protein conformation and dynamics within its structure may underlie the aggregation of SOD1 in ALS.</p