Myriocin (Myr) is a suicide inactivator of ceramide synthesis with a complex lipid multifunctional structure. Its biological activity is exerted at very low doses, and thus highly performing quantitative method are
needed [1]. The pharmacological development of Myr to modulate ceramide levels also requires currently unavailable ADME information in healthy and pathological animal models

C. Bucolo

C. Platania

E. Strettoi

F.M. Rubino

J. Rizzo

M. Dei Cas

P. Signorelli

R. Ghidoni

R. Pignatello

R.C. Paroni

AIR Universita degli studi di Milano

 1 
  
 374 
10.  Bergemann N., Parzer P., Runnebaum B., Resch F., Mundt C., Psychological Medicine, 37, 1427–1436 
(2007). 
11.  Roney J. R., Simmons Z. L., Adaptive Human Behavior and Physiology, 1, 30–40 (2015). 
12.  Driver H. S., Werth E., Dijk D. J., Borbély A. A.,Sleep Medicine Clinics, 3, 1–11 (2008). 
13.  Ellison P. T., Lipson S. F., Jasienska G., Ellison P. L., American Journal of Physical Anthropology, 134, 
513–519 (2007). 
 
 
MP-133 / PHARMACOKINETIC OF MYRIOCIN IN RABBIT’S EYES 
 
Michele Dei Cas 
(1)
 - Federico Maria Rubino 
(1)
 - Jessica RIzzo 
(1)
 - Signorelli Paola 
(1)
 - Enrica Strettoi 
(2)
 - 
Chiara Platania 
(3)
 - Claudio Bucolo 
(3)
 - Rosario Pignatello 
(4)
 - Riccardo Ghidoni 
(1)
 - Rita Clara Paroni 
(1)
 
 
University of Milan, Department of Health Sciences, Milan (1) - CNR Neuroscience Institute, CNR 
Neuroscience Institute, Pisa (2) - University of Catania, Department of Biomedical and Biotechnological 
Sciences, Catania (3) - University of Catania, Department of Pharmaceutical Sciences, Catania (4) 
 
Keywords: myriocin,pharmacokinetic,drug delivery, eye, qTrap 
 
Introduction 
Myriocin (Myr) is a suicide inactivator of ceramide synthesis with a complex lipid multifunctional structure. 
Its biological activity is exerted at very low doses, and thus highly performing quantitative method are 
needed [1]. The pharmacological development of Myr to modulate ceramide levels also requires currently 
unavailable ADME information in healthy and pathological animal models. 
 
Methods 
A 3200 qTRAP system was operated under manufacturer’s instructions to perform extensive tandem MS 
studies. LC and MS were optimized for the separation, detection, identification and quantification of Myrin 
aqueous humour, vitreous humor and retina of rabbit after different treatments. MRM scan mode was 
used as protocol, to tackle the ambiguities of some samples, EPI scan, MS3 and the use of HR-MS on a 6600 
qTOF was also crucial. 
 
Results 
Tissue levels of Myrare related to the dose, pharmaceutical formulation, administration route, and 
administration schedule. Four type of eye drop formulations were evaluated in rabbits: Myr in buffer 
solution, Myr in two different types of liposomes (neutral and cationic), Myr encapsulated in a novel type of 
solid nanolipid particles. In particular, solid nanolipid particles was found to be extremely efficacious for the 
delivery of Myrin the different areas of the eye. The slow release formulation produced a Tmax between 
180-240 minutes, with a maximum concentration respectively of 10 mg/mL in vitreous and 1.7 mg/g in 
retina. Biological activity of Myr was always confirmed in rabbit’s retina by a significant decrease in 
ceramides levels, compared to the physiological level established from untreated animals. Some untreated 
animals demonstrated the presence of a peak with spectroscopic and chromatographic characteristics of 
Myr. EPI scan, MS3, and the use of a HR-MS as protocol confirmed an upstream contamination. 
 
Conclusions 
A new pharmaceutical delivery system, such as solid lipid nanoparticles, allows Myr to accumulate into the 
retina by a non-invasive eye-drops administration, and to modulate sphingolipid levels. These results would 
be promising to study its efficacy in mouse pathological model of retinitis pigmentosa. MRM measurement 
needs alternative and/or complementary techniques to confirm eventual false-positives samples. 
 
Novel Aspect 
The use of HR-MS as protocol should be quite advantageous for predicting new metabolites and for 
 375 
removing unwanted matrix interferences. 
 
References 
1. Campisi G.M., Signorelli P., Rizzo J., Ghilardi C., Antognetti J., Caretti A., Lazarević J.S., Strettoi E., Novelli 
E., Ghidoni R., Rubino F.M., Paroni R. Biomed Chromatography; 31:e4026. 
https://doi.org/10.1002/bmc.4026 (2017) 
 
 
MP-134 / COMPARISON OF ESI, APCI AND APPI IONIZATION TECHNIQUES FOR TESTOSTERONE (T), 
DIHYDROTESTOSTERONE (DHT) AND ESTRADIOL (E2) LCMS/MS ASSAY 
 
Reena Desai 
(1)
 - Pekka Keski-Rahkonen 
(1,3)
 - D. Tim Harwood 
(2)
 - David J. Handelsman 
(1)
 
 
ANZAC Research Institute, University of Sydney, Sydney, NSW 2139, Australia (1) - Cawthron Institute, 
Nelson 7010, New Zealand (2) - Current address: International Agency for Research on Cancer, F-69372 
Lyon, France (3) 
 
Keywords: Comparing ionization techniques for steroids 
 
Introduction 
High sensitivity measurement at low concentrations of non-derivatized testosterone (T), 
dihydrotestosterone (DHT) and estradiol (E2) requires optimizing ionization technique but few matrix-
specific comparisons are available. We compared electrospray ionization (ESI), atmospheric pressure 
chemical ionization (APCI) and atmospheric pressure photoionization (APPI) for sensitivity and matrix 
interference in neat solutions and human serum. 
 
Methods 
LC instrumentation and conditions 
A Shimadzu Prominence HPLC system was used and consisted of a DGU-20A5 degasser, three LC-20 AD 
pumps, a SIL-20AT HC autosampler and a CTO-20A column oven (Shimadzu Scientiﬁc Instruments, Kyoto, 
Japan). The column was an Agilent Poroshell 120 SB-C18 (2.1 × 50 mm; 2.7 μm) with 0.3 μm in-line ﬁlter 
(Agilent Technologies). For the determination of LLOQs with standard solutions, column temperature was 
40°C, injection volume 20 μl, and mobile phase of 70% methanol/water, containing 0.1% (v/v) of formic 
acid for positive ESI and 2.5 mM ammonium hydroxide for negative ESI. APCI and APPI were used without 
mobile phase additions. For serum and tissue samples, a following gradient was employed (A: water, B: 
methanol): 0–1 min: 20% B, 1–8 min: 20 > 70% B, 8–10 min: 70% B, 10–12 min: 100% B, 12–16 min: 20% B. 
Flow rate was 0.3 ml/min, injection volume 40 μl and same mobile phase additions were used as for the 
isocratic separations. A ﬂow-line selection valve was used to divert the eluent to waste during 0–7 min and 
11–16 min. For all experiments with APPI, toluene was used as a dopant solvent, delivered with an LC-20 
AD pump with a ﬂow rate 10% of that of the mobile phase. 
MS instrumentation and conditions 
An API 5000 triple quadrupole MS was used with Turbo V (ESI, APCI) and PhotoSpray (APPI) ion sources (AB 
Sciex, Toronto, Canada). The APPI lamp was a DC-driven 10.0 eV krypton discharge lamp model PKS100 
from Heraeus (Hanau, Germany). Nitrogen was employed as ion source, curtain and collision gas (Peak 
NM20ZL, Peak Scientiﬁc, Inchinnan, UK). For the precursor ion selection and optimization of the MS 
parameters, 5 μ M solution of E2 in methanol was infused post-column into the mobile phase (70% 
methanol/water). 
The E2 infusion ﬂow rate was kept at 5% of the mobile phase ﬂow. Precursor and product ion selection was 
based on ion intensity. After establishing the MRM conditions, further optimization of the ion source 
parameters and the mobile phase ﬂow rate was made with on-column injections, which enabled signal-to-
noise (S/N) calculations. MS parameters not related to ionization were optimized and kept identical for 
each MRM transition. Both quadrupoles were set at unit resolution, cycle time was 250 ms and no signal 


Pharmacokinetic of myriocin in rabbit&#8217;s eyes

https://air.unimi.it/retrieve/handle/2434/611648/1132671/IMSC2018_Abstract_Book_374_Myr-eye.pdf

Pharmacokinetic of myriocin in rabbit’s eyes

Abstract

Similar works

Full text

Available Versions

AIR Universita degli studi di Milano

Pharmacokinetic of myriocin in rabbit&#8217;s eyes

Abstract

Similar works

Full text

Available Versions

AIR Universita degli studi di Milano

Pharmacokinetic of myriocin in rabbit’s eyes