Understanding the Manufacturing Process of Lipid Nanoparticles for mRNA Delivery Using Machine Learning.

Lipid nanoparticles (LNPs), used for mRNA vaccines against severe acute respiratory syndrome coronavirus 2, protect mRNA and deliver it into cells, making them an essential delivery technology for RNA medicine. The LNPs manufacturing process consists of two steps, the upstream process of preparing LNPs and the downstream process of removing ethyl alcohol (EtOH) and exchanging buffers. Generally, a microfluidic device is used in the upstream process, and a dialysis membrane is used in the downstream process. However, there are many parameters in the upstream and downstream processes, and it is difficult to determine the effects of variations in the manufacturing parameters on the quality of the LNPs and establish a manufacturing process to obtain high-quality LNPs. This study focused on manufacturing mRNA-LNPs using a microfluidic device. Extreme gradient boosting (XGBoost), which is a machine learning technique, identified EtOH concentration (flow rate ratio), buffer pH, and total flow rate as the process parameters that significantly affected the particle size and encapsulation efficiency. Based on these results, we derived the manufacturing conditions for different particle sizes (approximately 80 and 200 nm) of LNPs using Bayesian optimization. In addition, the particle size of the LNPs significantly affected the protein expression level of mRNA in cells. The findings of this study are expected to provide useful information that will enable the rapid and efficient development of mRNA-LNPs manufacturing processes using microfluidic devices.

Mutations in carboxy-terminal part of E2 including PKR/eIF2alpha phosphorylation homology domain and interferon sensitivity determining region of nonstructural 5A of hepatitis C virus 1b: their correlation with response to interferon monotherapy and viral load.

AIM: To study the amino acid substitutions in the carboxy (C)-terminal part of E2 protein and in the interferon (IFN) sensitivity determining region (ISDR) and their correlation with response to IFN and viral load in 85 hepatitis C virus (HCV)-1b-infected patients treated with IFN. METHODS: The C-terminal part of E2 (codons 617-711) including PKR/eIF2alpha phosphorylation homology domain (PePHD) and ISDR was sequenced in 85 HCV-1b-infected patients treated by IFN monotherapy. RESULTS: The amino acid substitutions in PePHD detected only in 4 of 85 patients were not correlated either with response to IFN or with viral load. The presence of substitutions in a N-terminal variable region (codons 617-641) in the C-terminal part of E2 was significantly correlated with both small viral load (33.9% vs 13.8%, P = 0.0394) and sustained response to IFN (25.0% vs 6.9%, P = 0.0429). Four or more substitutions in ISDR were significantly correlated with both small viral load (78.6% vs 16.2%, P < 0.0001) and sustained response to IFN (85.7% vs 2.9%, P < 0.0001). In multivariate analysis, ISDR in nonstructural (NS) 5A (OR = 0.39, P < 0.0001) and N-terminal variable region (OR = 0.51, P = 0.039) was selected as the independent predictors for small viral load, and ISDR (OR = 39.0, P < 0.0001) was selected as the only independent predictor for sustained response. CONCLUSION: The N-terminal variable region in the C-terminal part of E2 correlates with both response to IFN monotherapy and viral load and is one of the factors independently associated with a small viral load.

Application of spherical silicate to prepare solid dispersion dosage forms with aqueous polymers.

The objective of this study is to prepare and characterize solid dispersions of nifedipine (NP) using porous spherical silicate micro beads (MB) that were approximately 100 µm in diameter with vinylpyrrolidone/vinyl acetate copolymer (PVP/VA) and a Wurster-type fluidized bed granulator. Compared with previously reported solid dispersion using only MB, the supersaturation of NP dissolved from the proposed system of MB and PVP/VA was maintained during dissolution tests. The proposed system produced a solid dispersion product coated on MB, and morphology was maintained after the coating process to prepare solid dispersion; therefore, the powder characteristics, such as flowability of the proposed solid dispersion product, was tremendously preferable to that of the conventional spray-dried solid dispersions of NP with PVP/VA, expecting to make the consequent manufacturing processes easy for development. Another advantage in the terms of manufacturing is its simple process to prepare solid dispersion by spraying the drug and polymer that were dissolved in an organic solvent onto a MB in a Wurster-type fluidized bed granulator, thus, simplifying the optimization and scale-up with ease.

The fluctuations of viral load and serum alanine aminotransferase levels in chronic hepatitis C.

Although viral load of hepatitis C virus (HCV) is a predictor of response to interferon therapy, little is known about its fluctuations. We assessed its fluctuations and their correlation with serum alanine aminotransferase (ALT) levels. Viral load was prospectively measured bimonthly for 22 months in 109 patients. In 40 patients, viral load changed more than five fold. Changes were transient and always returned to the baseline levels. ALT levels changed more than three fold in 30 patients. Changes of viral load accompanied simultaneous changes of ALT levels in only 7 of 40 patients with changes of viral load. Mean viral load in 22 months was significantly correlated with mean ALT levels inversely (r = 0.278, P = 0.0036). Mean viral load was significantly higher in 27 patients with persistently normal ALT levels (452.0 +/- 342.5pg/ml) than in 30 patients with changes of ALT levels (202.4 +/- 215.0pg/ml) (P = 0.0016) and than in 52 patients without changes of ALT levels (301.1 +/- 295.4pg/ml) (P = 0.0458). Inverse correlation of viral load with ALT levels suggests that viral load is in suppression by inflammatory activity. However, changes of ALT levels infrequently accompanied simultaneous changes of viral load and vice versa, as often seen in chronic hepatitis B virus infection.

Practical approach to prepare solid dispersion drug product using spherical silicate.

The purpose of this study is to establish a novel approach for preparing a solid dispersion drug product using spherical silicate by a Wurster-type fluidized bed granulator. The spherical silicate used in this study has porous structure and ideal particle size for loading by a Wurster-type fluidized bed granulator. As model drugs, ibuprofen (IBU), indomethacin (IMC), and phenytoin (PNT) were used and the proposed approach was applied to prepare amorphous drug. All drugs could be loaded on the spherical silicate in an amorphous state. On the other hand, spray drying of spherical silicate suspended in IBU solution was conducted to prepare amorphous product of IBU as a reference; however, complete amorphization was not achieved. Dissolution profiles of each drug after loading on spherical silicate by a Wurster-type fluidized bed granulator were evaluated, and dramatic improvement of dissolution was observed compared with those of crystalline drug. In the proposed approach, specific surface area and particle size of spherical silicate were determined as a key factors to contribute to high yield of amorphous product.

Mutations in the nonstructural region 5B of hepatitis C virus genotype 1b: their relation to viral load, response to interferon, and the nonstructural region 5A.

The nonstructural 5B (NS5B) protein of hepatitis C virus possesses RNA-dependent RNA polymerase activity and plays an essential role in viral replication. The mutations in NS5B were determined and the correlation with viral load and response to interferon (IFN) were assessed. The entire NS5B region in 33 patients and its thumb domain in 62 patients was sequenced. The number of amino acid substitutions in the NS5B protein, that in thumb domain and the substitution at aa 389 was correlated with viral load and the response to IFN. Multivariate analysis selected only mutation in IFN sensitivity determining region (ISDR) as a factor associated with the viral load and response to IFN. The number of substitutions in the thumb domain and the substitution at aa 389 correlated with the number of substitutions in the ISDR. These results suggest that mutations in NS5B, especially in the thumb domain and at aa 389, have an important effect on viral load and the response to IFN, although they were dependent on mutations in ISDR. Further studies on the relationship between NS5B and NS5A (ISDR) are necessary to elucidate the mechanism of the correlation with viral load and the response to IFN.

Long term effects of phlebotomy on biochemical and histological parameters of chronic hepatitis C.

OBJECTIVES: There is considerable evidence that iron is a risk factor for liver injury in chronic hepatitis C. Known as iron reduction therapy, phlebotomy reduces serum ALT activity. This effect might continue with maintenance phlebotomy and result in slower progression of liver fibrosis. METHODS: We examined the biochemical parameters and liver histology of patients with chronic hepatitis C treated by maintenance phlebotomy. For biochemical evaluation, 25 patients were treated by initial phlebotomy to reduce serum ferritin levels to 10 ng/ml or less and then observed for 5 yr with maintenance phlebotomy to maintain the iron-deficient state. For histological evaluation, liver biopsies were performed before and after the study period in 13 of the patients. Thirteen patients who were virological nonresponders to interferon alone and had undergone second liver biopsies after more than 3 yr served as histological controls. RESULTS: Serum aminotransferase levels were decreased significantly by initial phlebotomy and remained at the same levels during the study period (p < 0.05). The grading scores were improved significantly in the study group (p < 0.05) and unchanged in the controls. The staging scores remained unchanged in the study group but were increased in the controls (p < 0.005). Disease progression was significantly different between the two groups (p < 0.05). CONCLUSIONS: These results suggest that phlebotomy with maintenance lowers serum aminotransferase levels, improves liver inflammation, and suppresses the progression of liver fibrosis in chronic hepatitis C.

Amino acid substitutions in the nonstructural region 5A of hepatitis C virus genotypes 2a and 2b and its relation to viral load and response to interferon.

OBJECTIVES: The interferon sensitivity-determining region (ISDR) in nonstructural region 5A (NS5A) of hepatitis C virus genotype 1b has been reported to correlate with response to interferon therapy and viral load. Recently the correlation between NS5A and response to interferon in genotype 2a was also reported. We examined the region of genotypes 2a and 2b corresponding to the ISDR of genotype lb to elucidate its correlation with response to interferon and viral load. METHODS: The sequences of amino acid positions 2213-2248 in NS5A were determined in 39 patients with genotype 2a and 12 patients with genotype 2b. RESULTS: In the patients infected with genotype 2a, the number of amino acid substitutions in the ISDR-corresponding region compared with the consensus sequence of genotype 2a was significantly correlated with viral load (p = -0.541, p < 0.001) and with response to interferon therapy (p < 0.05); 83% of the patients with three or more substitutions obtained sustained responses, whereas only 44% of those with less than three substitutions obtained sustained responses. Multivariate analysis confirmed that the number of substitutions in the ISDR-corresponding region of genotype 2a was one of the independent predictors of response to interferon therapy (discriminant coefficient = 1.35, p < 0.001). CONCLUSIONS: Substitutions in the ISDR-corresponding region in NS5A of hepatitis C virus genotype 2a was confirmed to correlate to viral load and response to interferon therapy. In genotype 2b, further work must be considered because of the small number of patients studied.