Preformulation Study of Highly Purified Inactivated Polio Vaccine, Serotype 3

Role of phenol red in the stabilization of the Sabin type 2 inactivated polio vaccine at various pH values

“…The effects of phenol red on pH stability were assessed again using Trp intrinsic spectroscopy and CD spectroscopy. CD spectroscopy was applied to observe the average status of the secondary structure of the virus capsid protein . When the pH values decreased from 7.0 to 4.0, the CD signal at approximately 220 nm decreased from −4.8 to −2.5 millidegrees, and the spectra became broader between 205 and 245 nm (Figure ).…”

“…Trp intrinsic fluorescence is the routine method to examine the tertiary structure around the Trp residues located in the virus capsid protein . As shown in Figure , when the pH changed from 7.0 to 4.0, the maximum peak intensity at approximately 376 nm decreased from 102 to 83, and to a certain extent, the spectra were broader between 365 and 395 nm.…”

“…CD spectroscopy was applied to observe the average status of the secondary structure of the virus capsid protein. 18 When the pH values decreased from 7.0 to 4.0, the CD signal at approximately 220 nm decreased from −4.8 to −2.5 millidegrees, and the spectra became broader between 205 and 245 nm (Figure 4). Two isodichroic points at 210 and 230 m also strongly proved that at various pH values, there were two-state transitions (α-coil random or β-coiled random) in the sIPV2 secondary structure.…”

“…Furthermore, D 2 O has been reported to maintain the immunogenicity of the OPV at extreme pH values (pH 2 or pH 9) . In addition, the antigen content of the IPV3 was evidently decreased at a low pH, and the aggregation occurred in the IPV3 solution at an acidic pH . In addition to high‐resolution structural data, several biophysical tools, such as tryptophan (Trp) intrinsic fluorescence, and circular dichroism (CD), were utilized to monitor the stabilization of proteins, including the capsid protein of the WT poliovirus and IPV3, under different pH conditions …”

“…16 In addition, the antigen content of the IPV3 was evidently decreased at a low pH, and the aggregation occurred in the IPV3 solution at an acidic pH. 17,18 In addition to high-resolution structural data, several biophysical tools, such as tryptophan (Trp) intrinsic fluorescence, and circular dichroism (CD), were utilized to monitor the stabilization of proteins, including the capsid protein of the WT poliovirus and IPV3, under different pH conditions. [19][20][21] However, the excipients for the pH stabilization of the IPVs, especially the Sabin IPV2, have only rarely been investigated.…”