Therapeutic salivary monitoring of IV busulfan in patients undergoing hematopoietic stem cell transplantation: a pilot study

Limited Sampling Strategies for Estimating Busulfan Area Under the Concentration-Time Curve: Based on Peak and Trough Concentrations in Saliva

Therapeutic drug monitoring for busulfan is currently performed by multiple plasma sampling. Saliva is considered a noninvasive therapeutic drug monitoring matrix. This study aimed to investigate intravenous busulfan pharmacokinetics (PK) in plasma and saliva, and establish a limited sampling strategy (LSS) for predicting the area under the concentration-time curve from time zero to infinity in plasma (AUC0-∞,p) by using saliva samples. Therefore, the PK of busulfan was studied in 37 Chinese patients. Pearson correlation analysis was used to evaluate the correlation between the AUC of busulfan in plasma and saliva. LSS models were established by the multiple linear regression analysis. The prediction error, the mean prediction error, and the root mean square error were used to evaluate the predictive accuracy. The agreement between the predicted and observed AUC0-∞ in saliva was investigated by the intraclass correlation coefficient and Bland-Altman analysis. The accuracy and robustness of the models were evaluated by using the bootstrap procedure. The result of PK analysis 62.2% of patients (23/37) was within the target range of AUC0-∞,p . A good correlation between saliva and plasma busulfan AUC0-∞ was observed (r = 0.63, p < .01). The bias and precision of the models 7 and 13 were less than 15%. The intraclass correlation coefficient exceeded 0.9, and the limits of agreement were within ±15%. The 2-point LSS model in saliva is a convenient and desirable approach to predict the AUC0-∞ of 4 times daily intravenous busulfan in plasma, which can be used to design personalized dosing for busulfan.

Saliva as a noninvasive sampling matrix for therapeutic drug monitoring of intravenous busulfan in Chinese patients undergoing hematopoietic stem cell transplantation: A prospective population pharmacokinetic and simulation study

Therapeutic drug monitoring (TDM) of busulfan (BU) is currently performed by plasma sampling in patients undergoing hematopoietic stem cell transplantation (HSCT). Saliva samples are considered a noninvasive TDM matrix. Currently, no salivary population pharmacokinetics (PopPKs) model for BU available. This study aimed to develop a PopPK model that can describe the relationship between plasma and saliva kinetics in patients receiving intravenous BU. The performance of the model in predicting the area under the concentration-time curve at steady state (AUCss ) based on saliva samples is evaluated. Sixty-six patients with HSCT were recruited and administered 0.8 mg/kg BU intravenously. A PopPK model for saliva and plasma was developed using the nonlinear mixed effects model. Bayesian maximum a posteriori (MAP) optimization was used to estimate the model's predictive performance. Plasma and saliva PKs were adequately described with a one-compartment model and a scaled central compartment. Body surface area correlated positively with both clearance and apparent volume of distribution (Vd), whereas alkaline phosphatase correlated negatively with Vd. Simulations demonstrated that the percentage root mean squared prediction error and lower and upper limits of agreements reduced to 10.02% and -16.96% to 22.86% based on five saliva samples. Saliva can be used as an alternative matrix to plasma in TDM of BU. The AUCss can be predicted from saliva concentration by Bayesian MAP optimization, which can be used to design personalized dosing for BU.

Dental consensus on HSCT - Part II: dental Care during HSCT

During the state of immune vulnerability in hematopoietic stem cell transplantation (HSCT), the patient has an increased risk of developing a vast number of complications, including severe problems in the oral cavity. These situations require professional oral care to act in the diagnosis and treatment of these conditions, as well as to develop prevention protocols to minimize patient's complications. Oral mucositis, opportunistic infections, bleeding, specific microbiota, taste, and salivary alterations are complications that can occur during HSCT and interfere with various aspects, such as pain control, oral intake, nutrition, bacteremia and sepsis, days of hospitalization and morbidity. Several guidelines have been published to address the role of professional oral care during the HSCT, we describe a consensus regarding these recommendations.

Pharmacokinetic Basis for Using Saliva Matrine Concentrations as a Clinical Compliance Monitoring in Antitumor B Chemoprevention Trials in Humans

This study reports the first clinical evidence of significantly high secretion of matrine in a multi-component botanical (Antitumor B, ATB) into human saliva from the systemic circulation. This is of high clinical significance as matrine can be used as a monitoring tool during longitudinal clinical studies to overcome the key limitation of poor patient compliance often reported in cancer chemoprevention trials. Both matrine and dictamine were detected in the saliva and plasma samples but only matrine was quantifiable after the oral administration of ATB tablets (2400 mg) in 8 healthy volunteers. A significantly high saliva/plasma ratios for C_max (6.5 ± 2.0) and AUC_0-24 (4.8 ± 2.0) of matrine suggested an active secretion in saliva probably due to entero-salivary recycling as evident from the long half-lives (t_1/2 plasma = 10.0 ± 2.8 h, t_1/2 saliva = 13.4 ± 6.9 h). The correlation between saliva and plasma levels of matrine was established using a population compartmental pharmacokinetic co-model. Moreover, a species-relevant PBPK model was developed to adequately describe the pharmacokinetic profiles of matrine in mouse, rat, and human. In conclusion, matrine saliva concentrations can be used as an excellent marker compound for mechanistic studies of active secretion of drugs from plasma to saliva as well as monitor the patient's compliance to the treatment regimen in upcoming clinical trials of ATB.

Nitrogenous compounds in the saliva and blood of cirrhotic patients: a cross-sectional study

OBJECTIVES

Serum increase of nitrogenous compounds (NC) in cirrhotic patients has been associated with the development of hepatic encephalopathy (HE). However, the relation between NC in saliva and HE is unclear. The objective of this study is to measure the levels of nitric oxide and urea in the blood and saliva in 38 cirrhotic patients and correlate them with clinical characteristics and presence and grades of HE.

MATERIAL AND METHODS

Automated enzymatic colourimetric assays were performed to determine the levels of NC. Diagnosis and severity of HE were determined based on the West Haven criteria and by using the inhibitory control test.

RESULTS

HE was diagnosed in 89.47% of the patients, with the majority (60.50%) presenting covert HE. With regard to the measurement of NC, although nitric oxide is moderately correlated with its amount in blood and saliva (r = 0.630; P < 0.001), only salivary levels were associated with the presence of ascites and ecchymosis (P = 0.013 and P = 0.030, respectively). In patients with HE, the serum levels of urea were higher (P = 0.013) than those in patients without HE or minimal HE.

CONCLUSIONS

Nitrogenous compounds in the saliva were correlated with neither the presence nor grades of HE, whereas in the blood, only urea was positively correlated with the severity and presence of HE.

CLINICAL RELEVANCE

Saliva is an excellent fluid for diagnosing several diseases, but it does not seem to be able to collaborate with the identification of HE.

Assessment of bone metabolism biomarkers in serum and saliva of cirrhotic patients

OBJECTIVE

To assess the serum and salivary levels of biomarkers related to bone metabolism in cirrhotic patients as well as the evidence of osteoporotic changes on panoramic radiographs.

MATERIALS AND METHODS

Thirty-eight cirrhotic patients underwent anamnesis and physical examination. Specimens of blood and saliva were collected for evaluation by using Luminex™ xMAP technology to quantify RANKL, OPG, IL-1β, IL-6 and TNF-α. Panoramic radiographs were evaluated based on the mandibular cortical index (MCI) and the resulting data were compared to the expression of biomarkers in serum and saliva. Descriptive data analysis was performed and the Mann-Whitney's test and Spearman's correlation were used.

RESULTS

Most of the sample consisted of males (68.4%) who had cirrhosis mostly resulting from alcoholism (28.9%). Median concentration values of RANKL (74.44 pg/mL), IL-1 β (45.91 pg/mL), IL-6 (67.69 pg/mL) and TNF-α (5.97 pg/mL) in saliva were higher than those observed in serum. In 72.7% of the panoramic radiographs, MCI was found to be suggestive of osteoporotic changes. No statistically significant correlation was observed between salivary and serum expressions of biomarkers or between biomarkers and MCI.

CONCLUSION

RANKL, OPG, IL-1β, IL-6 and TNF-α are expressed differently in serum and saliva and the concentration of these biomarkers is not related to MCI.

CLINICAL RELEVANCE

This study contributes to the study of the mechanisms of osteoporosis in cirrhotic individuals.

Is Salivary Busulfan the Cause of Oral Mucositis and the Changes in Salivary Antioxidant Enzymes After Hematopoietic Cell Transplantation?

BACKGROUND

To determine whether the busulfan (Bu) present in saliva during hematopoietic cell transplantation (HCT) conditioning correlates with oral mucositis and the changes in salivary antioxidant enzymes.

METHODS

Bu levels in the plasma and saliva of 19 patients who received HCTs were quantified. Salivary flow and salivary superoxide dismutase and catalase activities were measured during HCT. For the toxicity analysis of salivary Bu, an in vitro assay was conducted by exposing human keratinocytes to artificial saliva containing Bu.

RESULTS

Plasma and salivary Bu concentrations were very similar (rho = 0.92, P < 0.001). Salivary Bu concentration correlated with the degree of oral mucositis severity (rho = 0.391, P = 0.029) and was inversely proportional to salivary superoxide dismutase and catalase activities (rho = -0.458, P = 0.036; rho = -0.424, P = 0.043, respectively). Cells exposed to Bu-containing saliva had fewer viable cells (P < 0.01) and more apoptotic cells (P = 0.001) than those exposed to non-Bu-containing saliva.

CONCLUSIONS

Bu found in saliva during HCT conditioning was correlated with severe oral mucositis and the reduction in salivary antioxidative activity. Furthermore, Bu can be toxic to keratinocytes.

Dried Plasma Spots and Oral Fluid as Alternative Matrices for Therapeutic Drug Monitoring of Busulfan: Analytical Method Development and Clinical Evaluation

BACKGROUND

Busulfan (BU) is an alkylating agent with a narrow therapeutic index and high intraindividual pharmacokinetic variability used in conditioning therapy for hematopoietic stem cell transplantation. Monitoring BU exposure during high-dose conditioning regimens is recommended and positively impacts outcomes. We aimed to develop, validate, and apply a ultra-high-performance liquid chromatography-mass spectrometry (MS)/MS assay to measure BU concentrations in oral fluid and dried plasma spots (DPS) as alternative matrices to plasma.

METHODS

We prepared plasma and oral fluid samples by protein precipitation and DPS after liquid extraction. We analyzed extracts using an LC-MS/MS system with an Acquity HSS T3 column in the positive electrospray ionization mode. The method was validated and applied to 79 paired plasma and oral fluid samples from 7 patients on BU conditioning treatment. DPS were prepared by pipetting plasma onto Whatman 903 paper. The correlation between BU in plasma, oral fluid, and DPS samples was evaluated.

RESULTS

Run time was 4.0 minutes. The assay was linear at 50-5000 ng mL-1 (r > 0.99), precise (1.9%-5.3% oral fluid and 1.8%-5.9% DPS), and accurate (98.1%-108.9% oral fluid and 93%-103.1% DPS). BU was stable in DPS at 23°C for 24 hours. BU levels in oral fluid (r = 0.927) and DPS (r = 0.982) were significantly correlated with plasma. Despite the good correlation, we found a wide variation between oral fluid and plasma levels. The area under curves (AUCs) calculated with oral fluid concentrations were 79.1%-167.1% of plasma AUCs. Bland-Altman plots found a better agreement for DPS, with AUCs estimated from corrected DPS levels at 83.1%-114.1% of plasma values.

CONCLUSIONS

We developed and validated a simple and fast ultra-high-performance liquid chromatography-MS/MS assay to measure BU in oral fluid and DPS. The results do not support the use of oral fluid as a matrix for routine therapeutic drug monitoring of BU. The AUC estimated from BU measurements in DPS was comparable to that in plasma, supporting the use of DPS in BU therapeutic drug monitoring as an alternative matrix, with adequate short-term stability and logistic advantages.