Influence of filtering on the effective concentration and sterility of a 2% cyclosporine ophthalmic solution: a quality improvement perspective

BACKGROUND

Pharmaceutical companies do not sell formulations for all diseases; thus, healthcare workers have to treat some diseases by concocting in-hospital preparations. An example is the high-concentration 2% cyclosporine A (CyA) ophthalmic solution. Utilizing a filter in sterility operations is a general practice for concocting in-hospital preparations, as is the case for preparing a 2% CyA ophthalmic solution. However, whether filtering is appropriate concerning the active ingredient content and bacterial contamination according to the post-preparing quality control of a 2% CyA ophthalmic solution is yet to be verified.

METHODS

We conducted particle size, preparation concentration, and bacterial contamination studies to clarify aforementioned questions. First, we measured the particle size of CyA through a laser diffraction particle size distribution. Next, we measured the concentration after preparation with or without a 0.45-µm filter operation using an electrochemiluminescence immunoassay. Finally, bacterial contamination tests were conducted using an automated blood culture system to prepare a 2% CyA ophthalmic solution without a 0.45 μm filtering. Regarding the pore size of the filter in this study, it was set to 0.45 μm with reference to the book (the 6th edition) with recipes for the preparation of in-hospital preparations edited by the Japanese Society of Hospital Pharmacists.

RESULTS

CyA had various particle sizes; approximately 30% of the total particles exceeded 0.45 μm. The mean ± standard deviation of filtered and non-filtered CyA concentrations in ophthalmic solutions were 346.51 ± 170.76 and 499.74 ± 76.95ng/mL, respectively (p = 0.011). Regarding bacterial contamination tests, aerobes and anaerobes microorganisms were not detected in 14 days of culture.

CONCLUSIONS

Due to the results of this study, the concentration of CyA may be reduced by using a 0.45-µm filter during the preparation of CyA ophthalmic solutions, and furthermore that the use of a 0.45-µm filter may not contribute to sterility when preparing CyA ophthalmic solutions.

Determination of the Optimal Wavelength of the Hemolysis Index Measurement

Many biochemical auto-analyzers have methods that measure the hemolysis index (HI) to quantitatively assess the degree of hemolysis. Past reports on HI are mostly in vitro studies. Therefore, we evaluated the optimal wavelength of HI measurement ex vivo using clinical samples. Four different wavelengths (410/451 nm: HI-1, 451/478 nm: HI-2, 545/596 nm: HI-3 and 571/596 nm: HI-4) were selected for HI measurement, and correlations were examined from the measurement results of 3890 clinical samples. Another set of 9446 clinical samples was used to examine the correlation of HI with lactate dehydrogenase (LDH), aspartate aminotransferase (AST) and potassium (K). Strong correlations were found between HI-4 and HI-1 and between HI-4 and HI-3. HI-1 and HI-2 cannot correctly assess hemolysis for high bilirubin samples, and HI-3 cannot correctly assess hemolysis for high triglyceride samples. LDH, AST and K correlated positively with HI-4 in clinical samples. For every 1-unit increase in HI-4, LDH increased by 19.51 U/L, AST by 1.03 U/L and K by 0.061 mmol/L, comparable to reports of other studies. In clinical samples, HI-4 was less susceptible to bilirubin and chyle and reflected well the changes in LDH, AST and K caused by hemolysis. This suggested that the optimal wavelength for HI measurement is 571 nm.

What is the best wavelength for the measurement of hemolysis index?

BACKGROUND

Hemolysis is a common problem in the handling of serum specimens. The hemolysis index (HI) provides a warning of hemolysis in auto-analyzers. However, HI has not been standardized, and each laboratory's original method is applied. Especially, the wavelength used for HI measurement is different in each laboratory. Thus, we investigated the warning ability of HI at various wavelengths.

METHODS

We selected 4 wavelength types, and each HI was measured and calculated (410 nm/HI-1, 451 nm/HI-2, 545 nm/HI-3, and 571 nm/HI-4). To compare the 4 HI types, we investigated the influence of 3 interference components using artificially hemolyzed specimens (AHSs). We also investigated both the relationship between HI and hemoglobin concentration (Hb) and that between HI and 31 biochemical test values in AHSs.

RESULTS

In the interference assessment, only HI-4 showed no influence on the 3 interference components. The correlation between Hb and HI-4 was very strong (r_S = 0.9987). A 1-unit increase in HI-4 corresponded to a 14.8-mg/dL increase in Hb.

CONCLUSION

We found the best wavelength for HI to be at or near 571 nm.

[Clinical assessment of contrast-enhanced ultrasonography for the diagnosis of gall bladder diseases]

We evaluated the efficacy of contrast-enhanced ultrasonography (CEUS) with intra-arterial injection of CO2 microbubbles in 37 cases of gall bladder diseases. CEUS clearly visualized arterial flow and vascularity in every lesions without debris and gave us the precise information of vascular structure for the differential diagnosis of gall bladder tumors. For example, highly bifurcated tumor vessels and strong enhancement was observed in gall bladder cancer and we could detect relatively strong enhancement along the lumen with lack of enhancement of Rokitansky-Aschoff sinus in localized-type adenomyomatosis. Though CEUS is now an invasive modality, it will enable us to understand the non-invasive modality such as color doppler imaging with intra-venous administration of microbubbles in the future.

Endoscopic ultrasonographic-guided punctured pancreatic ductography: an initial and successful trial

A 71-year-old male suffering from an intraductal papillary tumor of the pancreas was admitted to our hospital for further investigation. Diagnostic trials, including endoscopic retrograde pancreatography, did not produce an adequate ductography because of a large amount of mucinous fluid. Therefore, we performed endoscopic ultrasonographic-guided punctured pancreatic ductography (EPPD). This procedure was safely performed without any complications. We report this initial and successful trial of EPPD.