Use of salivary acetaminophen concentration to assess gastric emptying rate of liquids

Abstract

The gastric emptying rate (GER) of liquids can be quantified by calculating the rate of acetaminophen absorption from serial plasma concentrations. As acetaminophen concentrations in saliva are well correlated with those in plasma, the salivary concentrations may be suitable for use in GER measurement. To evaluate such suitability, salivary and plasma samples were simultaneously obtained from seven healthy volunteers at 0, 0.25, 0.5, 0.75, 1.0, 1.5, and 2.0 h after they had ingested 20 mg/kg of acetaminophen mixed with a 200-ml liquid meal (200 kcal). Commonly used parameters for the rate of acetaminophen absorption were calculated from the salivary and plasma data, including the maximum concentration (Cmax), the time to Cmax (t(max)), the concentration at 0.75 h (C0.75), the area under the curve from 0 to 1.0 h (AUC1.0), and the AUC(0.5)/AUC(2.0) ratio. The mean (SD) salivary/plasma concentration ratio was 2.48 (1.47) at 0.25 h, and the means were almost unity afterwards. Significant correlations between saliva and plasma were found in all parameters studied (r = 0.77-0.90; P < 0.05). However, except for t(max), the salivary parameters overestimated those of plasma. The present results suggest that: (1) the salivary acetaminophen concentration at 0.25 h (C0.25) is a poor reflection of plasma C0.25 (2) thereby the parameters embodying salivary C0.25 such as AUC1.0 and the AUC0.5/AUC2.0 ratio, are unreliable, and (3) liquid GER can be assessed by salivary t(max) with minimal distress to the patient.

Oral medication dose form alteration: patient factors and the effect of adding thickened fluids

“…The peak paracetamol concentration measured in saliva (Cmax) for the present study (4.0 -15.4 µg/mL) was in agreement with salivary paracetamol concentrations in other studies (5 -18.5 µg/mL) (Sanaka et al, 2000, Schaiquevich et al, 2002. Cmax and tmax are dependent on the extent and the rate of drug absorption, and measurement of these is influenced by the number of samples collected for analysis.…”

“…When paracetamol powder dispersed in a nutrient drink was held in the mouth for 1 minute, oral contamination was believed to have affected salivary paracetamol measurements and affected reliability of the readings for up to 15 minutes (Sanaka et al, 2000). Furthermore, the use of 250 mL of water is not representative of what happens in practice for dysphagic patients using jam or thickened fluids to take their medicines, and may have altered the clearance from the stomach.…”

“…Paracetamol absorption pharmacokinetics are assessed by quantifying paracetamol levels in saliva; earlier studies have established that good correlation exists between paracetamol in saliva and venous blood (Adithan and Thangam, 1982, Wade et al, 2008, Sanaka et al, 2000, and quantification of paracetamol in saliva is well established (Schaiquevich et al, 2002). Additionally, saliva presents a low risk and economical approach that does not require trained personnel for collection (Mullangi et al, 2009).…”

“…Distribution of paracetamol between plasma and saliva via the salivary glands is very well established, with several studies showing a significant correlation between plasma and saliva levels (Adithan and Thangam, 1982, Wade et al, 2008, Sanaka et al, 2000, Schaiquevich et al, 2002. In addition, studies have shown higher levels during the first 50 minutes after the administration of paracetamol followed by constant levels during the elimination phase for both saliva and plasma (Adithan andThangam, 1982, Kamali et al, 1987b).…”

Stamping surface-enhanced Raman spectroscopy for label-free, multiplexed, molecular sensing and imaging

“…These concentrations are relevant for successful detection in urine. 13,14 After stamping, we could not find the dry mark using bright-field microscopy because both molecules are colorless, however, SERS maps successfully provided the spatial distribution information of both. As shown in the bottom row of Fig.…”