Investigation of oral malodor prevention by dentifrices as measured by VSC reduction.

The oral malodor reduction efficacy of dentifrices containing stannous fluoride (SnF2) or zinc plus arginine (Zn/Arg) was evaluated using a halimeter to measure volatile sulfur compounds (VSCs) in two randomized, controlled, single-blind, cross-over pilot clinical trials. Study 1 (N= 16) had five 1100 ppm F dentifrices and five treatment periods: negative control (NC): 0.243% sodium fluoride (NaF); SnF2A: 0.454% SnF2+ pyrophosphate; SnF2B: 0.454% SnF2+ sodium hexametaphosphate; SnF2C: 0.454% SnF2+ citrate; and SnF2D: experimental 0.454% SnF2with increased bioavailable Sn. Study 2 (N= 16) had four 1450 ppm F dentifrices and four treatment periods: NC: 0.1% NaF + 0.76% sodium monofluorophosphate; Zn/Arg: NaF + zinc + arginine; SnF2E: 0.454% SnF2+ 0.078% NaF + sodium hexametaphosphate; SnF2F: 0.454% SnF2+ 0.078% NaF + citrate. Each period took 96 h; baseline (day 0) morning to day 4 morning. Subjects brushed 2x/day with the treatment dentifrice. VSC levels were measured in the morning, prior to morning brushing, on days 0 and 4. Changes in VSC scores from day 0 to day 4 were assessed using a mixed-model analysis of covariance for cross-over studies. In study 1, SnF2dentifrices B, C and D showed statistically significant reductions (31.3%, 24.8%, 34%, respectively) in VSC scores versus baseline (p< 0.001); the benefits of these treatments versus NC and SnF2dentifrice A were statistically significant (p⩽ 0.001). In study 2, SnF2dentifrices E and F showed statistically significant reductions (31.2%, 22.1%, respectively) in VSC scores versus baseline (p⩽ 0.010); the benefits of these treatments versus NC and the Zn/Arg dentifrice were statistically significant (p⩽ 0.035). The Zn/Arg dentifrice showed a significant increase of 35.2% (p< 0.001) in VSC scores versus baseline. These studies demonstrated that SnF2dentifrices can provide significant oral malodor reductions, but the benefit is formulation dependent. The presence of SnF2is not sufficient to ensure efficacy. The Zn/Arg dentifrice increased VSC levels, indicating greater malodor.Clinical Trial Numbers: 20190429 and 20191028.

Rapid pKa estimation using vacuum-assisted multiplexed capillary electrophoresis (VAMCE) with ultraviolet detection.

A rapid approach for estimating the pK(a) value of small organic molecules was developed using vacuum-assisted multiplexed capillary electrophoresis (VAMCE) with ultraviolet detection. The VAMCE method employed a 96-capillary array, arranged in a standard 8 x 12 microtiter plate configuration, with each row of capillaries filled with 12 individual running buffers of equal ionic strength (I = 50 mM) covering a pH range from 2.2 to 10.7. A separate compound was injected hydrodynamically into each row of capillaries allowing the estimation of pK(a) values for eight compounds in a single run. The application of a vacuum during the separation generated a bulk fluid flow and allowed the electrophoretic separation to be completed within 5 min. The complete VAMCE method, conditioning, and electrophoretic separation was optimized to allow the pK(a) estimation for between 128 to 168 compounds in an 8-h period. The VAMCE method provided a reliable approach for estimating pK(a) values both within- and between-day. The pK(a) values for a series of 96 compounds estimated by VAMCE agreed well with some of literature pK(a) values with an average absolute difference of 0.22 log units.