Justifying the lack of incurred sample reproducibility in a study: considerations and strategies.

In 2012 with the issuance of its Guideline on Bioanalytical Method Validation, the European Medicine Agency (EMA) made the incurred sample reproducibility (ISR) assessment a requirement for studies to be submitted to European authorities. Since then 2012, European agencies have started to issue deficiencies to pharmaceutical companies for lack of ISRs in studies submitted recently but performed prior to the issuance of the 2012 Guideline. It now becomes the applicant's responsibility to justify scientifically the departure from the new guideline even for less recent studies. This article details the different strategies to provide an adequate justification for the absence of ISR data in studies performed prior to February 2012 but submitted to European agencies after that date.

Spectroscopic characterization of nanoErythrosomes in the absence and presence of conjugated polyethyleneglycols: an FTIR and (31)P-NMR study.

We have recently developed from red blood cells a new delivery system called nanoErythrosomes. These nanovesicles offer a high degree of versatility for the encapsulation of biological or nonbiological compounds and for the binding of targeting agents. In particular, polyethyleneglycols can be conjugated by a covalent link to the basic amino acid residues constitutive of the different proteins. The binding of polyethyleneglycols to the nanoErythrosome membrane could be interesting for the therapeutic use of this delivery system since it could overcome heterologous immunogenicity and reduce rapid clearance from circulation. In the present study, we have investigated the effect of temperature on the nanoErythrosome behavior in the absence and presence of conjugated polyethyleneglycols. More specifically, Fourier transform infrared (FTIR) spectroscopy has been used to evaluate the lipid order and dynamics, the hydration and the degree of protein aggregation of the nanoErythrosomes after covalent binding of polyethyleneglycols having molecular weights of 2000 and 5000 g mol(-1). The results indicate that the nanoErythrosome lipid chain order is not significantly affected by heating the nanoErythrosomes at temperatures up to 50 degrees C. They also indicate that the nanoErythrosome proteins aggregate irreversibly at temperatures above 37 degrees C, this effect being abolished in the presence of polyethyleneglycols. The presence of polyethyleneglycols decreases the accessibility of water to the lipid head groups. On the other hand, 31P-nuclear magnetic resonance (NMR) and electron microscopy results reveal that the presence of polyethyleneglycols prevents the aggregation of the nanoErythrosome structures.