Development of an effective cleaning technique and ancillary analytical method for estimation of residues of selected kinase inhibitors from stainless steel and glass surfaces by swab sampling

Importance of cleaning validation in the pharmaceutical industry cannot be overstated. It is essential for preventing cross-contamination, ensuring product quality & safety, and upholding regulatory standards. The present study involved development of an effective cleaning method for five selected kinase inhibitors binimetinib (BMT), selumetinib (SMT), brigatinib (BGT), capmatinib (CPT), and baricitinib (BRT). For checking the effectiveness of the developed cleaning technique, a sensitive and specific RP-HPLC based analytical method employing a diode array detector has been established to quantitate drug residue on glass and stainless steel surfaces. A reproducible swab sampling protocol utilizing TX714A Alpha swabs wetted with an extracting solvent has been developed to collect representative samples from both surfaces. Chromatographic separation of selected kinase inhibitors was achieved in gradient mode using an Agilent Zorbax eclipsed C18 column with acetonitrile and 10 mM ammonium formate as the mobile phase. The analytes were chromatographically separated in a 12 min run time. The mean swab recovery for each drug from glass and stainless steel surfaces exceeded 90%. Cleaning with IPA (70%) and acetone (70%) effectively removed residues for all five drugs. A solution comprising 10 mM SDS with 20% IPA demonstrated good efficacy in cleaning residues of BGT, BRT, and CPT, but exhibited lower efficacy for SMT and BMT.

Influence of cleaning methods after 3D printing on two-body wear and fracture load of resin-based temporary crown and bridge material

OBJECTIVES

To investigate the impact of different cleaning methods on the fracture load and two-body wear of additively manufactured three-unit fixed dental prostheses (FDP) for long-term temporary use, compared to the respective outcomes of milled provisional PMMA FDPs.

MATERIALS AND METHODS

Shape congruent three-unit FDPs were 3D printed using three different resin-based materials [FPT, GCT, NMF] or milled [TEL] (N = 48, n = 16 per group). After printing, the FDPs were cleaned using: Isopropanol (ISO), Yellow Magic 7 (YEL), or centrifugal force (CEN). Chewing simulation was carried out with a vertical load of 50 N (480,000 × 5 °C/55 °C). Two-body wear and fracture load were measured. Data were analyzed using global univariate ANOVA with partial eta squared, Kruskal-Wallis H, Mann-Whitney U, and Spearman's rho test (p < 0.05).

RESULTS

TEL showed less wear resistance than FPT (p = 0.001) for all cleaning methods tested. Concerning vertical material loss, NMF and GCT were in the same range of value (p = 0.419-0.997), except within FDPs cleaned in ISO (p = 0.021). FPT showed no impact of cleaning method on wear resistance (p = 0.219-0.692). TEL (p < 0.001) showed the highest and FPT (p < 0.001) the lowest fracture load. Regarding the cleaning methods, specimens treated with ISO showed lower fracture load than specimens cleaned with CEN (p = 0.044) or YEL (p = 0.036).

CONCLUSIONS

The material selection and the cleaning method can have an impact on two-body wear and fracture load results.

CLINICAL RELEVANCE

Printed restorations showed superior two-body wear resistance compared to milled FDPs but lower fracture load values. Regarding cleaning methods, ISO showed a negative effect on fracture load compared to the other methods tested.

[Advances in Lymph Node Metastasis and Lymph Node Dissection in Early Non-small Cell Lung Cancer]

肺癌是目前我国发病率和死亡率均居首位的恶性肿瘤，其中以非小细胞肺癌为主要病理类型。淋巴结转移是非小细胞肺癌最常见和最主要的转移途径，也是影响肺癌分期和预后最重要的因素。由于目前通过现有手段术前很难准确判断早期非小细胞肺癌患者的淋巴结受累情况。因此，在早期非小细胞肺癌中，尤其是在临床Ⅰ期非小细胞肺癌患者中，淋巴结清扫方式一直存在很大争议。本文就非小细胞肺癌淋巴结转移的规律及清扫方式进行综述。

Long-term effects of seven cleaning methods on light transmittance, surface roughness, and flexural modulus of polyurethane retainer material

OBJECTIVES

To evaluate the long-term effects of seven different cleaning methods on light transmittance, surface roughness, and flexural modulus of a polyurethane retainer material.

MATERIALS AND METHODS

Polyurethane retainer specimens (Vivera®, Align Technology Inc) (70 specimens, n = 10 per method, 50.8 mm × 12.7 mm × 1.0 mm) were exposed to seven cleaning methods twice a week for 6 months. Before treatment and after 6 months, light transmittance, surface roughness, and flexural modulus of the specimens were quantified. Qualitative assessment of randomly selected specimens from each solution was performed at baseline and after 6 months using a scanning electron microscope. Statistical analyses were performed at the .05 significance level.

RESULTS

Of the three test variables, light transmittance through the specimens was the only one that changed significantly from baseline to 6 months for all cleaning solutions, with all of them causing a decrease. However, except for 0.6% sodium hypochlorite showing a change in surface roughness values and 2.5% vinegar and toothbrushing showing an increase in flexural modulus, none of the other four cleaning methods resulted in significant changes in surface roughness or flexural modulus values for the polyurethane specimens between baseline and after 6 months.

CONCLUSIONS

Of the seven cleaning methods, Invisalign® cleaning crystals, Polident®, and Listerine® showed the least amount of change in light transmittance values for the polyurethane specimens over 6 months, and they had no effect on surface roughness and flexural modulus values.

The Effect of Temporary Cement Cleaning Methods on the Retention of Crowns

PURPOSE

To evaluate the effect of temporary cement cleaning methods on the retention of cemented crowns using zinc phosphate cement and resin-modified glass ionomer cement.

MATERIALS AND METHODS

Forty titanium specimens were fabricated to simulate prepared molars with minimally retentive taper. The Ni-Cr cast crowns were fabricated, temporarily cemented, and separated. The specimens were divided into four groups according to the temporary cement cleaning method (n = 10) as follows: control group (no temporary cementation), orange solvent group, ultrasonic cleaning group, and air-abrasion group. After the cleaning procedures, the specimens were cemented with definitive cements (zinc phosphate cement and resin-modified glass ionomer, RMGI, cement) and subjected to thermocycling (5000 cycles, 5-55°C, dwell time, 10 seconds). The tensile bond strength of each specimen was measured using a universal testing machine, and the results were analyzed using the Kruskal-Wallis and Mann-Whitney U test (α = 0.05).

RESULTS

When cemented with zinc phosphate cement, the statistical analysis showed that the value of the air-abrasion group was significantly higher than those of the other groups (p < 0.01). There was no statistically significant difference among the other groups. When cemented with RMGI cement, the air-abrasion group showed the lowest value, and the control group showed the highest value (p < 0.01). The difference between the ultrasonic cleaning group and the orange solvent group was not statistically significant.

CONCLUSION

The use of temporary cement did not have a significant influence on retention of permanently cemented crowns when zinc phosphate cement was used for permanent cementation. Airborne-particle abrasion after provisional cementation improved retention of crowns cemented with zinc phosphate cement; however, the use of temporary cement significantly decreased retention of permanently cemented crowns when RMGI cement was used regardless of the temporary cement cleaning method.

A cleaning method to minimize contaminant luminescence signal of empty sample carriers using off-the-shelf chemical agents

Signals acquired during thermoluminescence or optically stimulated luminescence measurements must be completely free of any spurious and/or contamination signals to assure the credibility of the results, especially during exploratory research investigating the luminescence behavior of new materials. Experiments indicate that such unwanted signals may also stem from new (unused) and used empty sample carriers, namely cups and discs, which are widely used for such measurements, probably due to contamination from a fluorite and/or silica-related source. Fluorite and/or silicone oil appear to be the most likely sources of contamination, thus, their removal, along with any other possible source that exhibits undesirable luminescence behavior, is necessary. Conventional cleaning methods fail to eliminate such contaminants from empty cups and discs. In this work a new cleaning method is proposed incorporating off-the-shelf chemical agents. Results of thermoluminescence measurements highlight the efficiency of the new cleaning process, since it can completely remove any observed contaminants from both new and used sample carriers, of various shapes and/or materials. Consequently their signal is minimized even at relatively high beta-doses, where it is prominent, resulting in a clean and only sample-attributed signal.

Evaluation of removal forces of implant-supported zirconia copings depending on abutment geometry, luting agent and cleaning method during re-cementation

PURPOSE

To evaluate the effects of different abutment geometries in combination with varying luting agents and the effectiveness of different cleaning methods (prior to re-cementation) regarding the retentiveness of zirconia copings on implants.

MATERIALS AND METHODS

Implants were embedded in resin blocks. Three groups of titanium abutments (pre-fabricated, height: 7.5 mm, taper: 5.7°; customized-long, height: 6.79 mm, taper: 4.8°; customized-short, height: 4.31 mm, taper: 4.8°) were used for luting of CAD/CAM-fabricated zirconia copings with a semi-permanent (Telio CS) and a provisional cement (TempBond NE). Retention forces were evaluated using a universal testing machine. Furthermore, the influence of cleaning methods (manually, manually in combination with ultrasonic bath or sandblasting) prior to re-cementation with a provisional cement (TempBond NE) was investigated with the pre-fabricated titanium abutments (height: 7.5 mm, taper: 5.7°) and SEM-analysis of inner surfaces of the copings was performed. Significant differences were determined via two-way ANOVA.

RESULTS

Significant interactions between abutment geometry and luting agent were observed. TempBond NE showed the highest level of retentiveness on customized-long abutments, but was negatively affected by other abutment geometries. In contrast, luting with Telio CS demonstrated consistent results irrespective of the varying abutment geometries. Manual cleaning in combination with an ultrasonic bath was the only cleaning method tested prior to re-cementation that revealed retentiveness levels not inferior to primary cementation.

CONCLUSION

No superiority for one of the two cements could be demonstrated because their influences on retentive strength are also depending on abutment geometry. Only manual cleaning in combination with an ultrasonic bath offers retentiveness levels after re-cementation comparable to those of primary luting.