A prospective randomized controlled trial comparing simethicone, N-acetylcysteine, sodium bicarbonate and peppermint for visualization in upper gastrointestinal endoscopy.

OBJECTIVES: Early cancer detection is crucial in improving the patients' quality of life and upper gastrointestinal endoscopy (EGD) plays a key role in this detection. Many clearing mechanisms may be applied to create good endoscopic visualizations for the upper gastrointestinal tract using mucolytic agents, antifoaming agents, proteolytic enzymes and neutralizers. The aim of this study is to compare the effects of simethicone, N-acetylcysteine (NAC), sodium bicarbonate and peppermint as pre-medications for visualization of esophagogastroduodenoscopy (EGD). METHODS: This study was a single center prospective randomized controlled trial. The patients were randomly allocated to one of four treatment groups. Group A: water; Group B: water with simethicone; Group C: water with simethicone plus NAC 600 mg; Group D: water with simethicone, NAC, sodium bicarbonate and peppermint. RESULTS: A total of 128 patients were enrolled and evaluated in this study. Total visibility score (TVS) of Groups A, B, C, and D were 13.4 ± 1.86, 10.5 ± 1.45, 7.15 ± 0.98 and 6.4 ± 1.43, respectively. Group D showed lower TVS than other groups. The procedural durations of Groups C and D were significantly shorter than Group A. The volume of solution for mucosal cleansing of Groups C and D was significantly lower than Groups A and B. CONCLUSIONS: The application of simethicone plus NAC is safe, improves endoscopic visualization and requires a minimal amount of mucosal cleansing solution. The addition of sodium bicarbonate and peppermint further improved visualization for the upper and lower gastric body. Thai Clinical Trials Registry (TCTR) with a reference number; TCTR20190501002.

Evaluation in vitro and in vivo of dimethicone transdermal therapeutic systems. Influence of propylene glycol on drug release.

Coumarin-containing transdermal drug delivery systems were studied in vitro for drug release and in vivo in rats for drug absorption. The matrix of the transdermal delivery system, dimethicone, was a commercially available silicone elastomer. The devices containing 1, 3 and 5% coumarin released in vitro 8.8 (87.4%), 23.4 (74.5%) and 31.6 mg (63.3%) of drug within 24 h. The device containing 5% coumarin was selected for further studies in which 5, 10, 20, 30, 50 and 70% propylene glycol was added. Up to 20% propylene glycol content did not change the amount released. The preparations with 30, 50 and 70% propylene glycol released 69.3, 73.6 and 87.9%, respectively. The 50 and 70% preparations were physically not acceptable. Only the preparations containing 5% coumarin without propylene glycol and 5% coumarin and 30% propylene glycol in the elastomer were evaluated in vivo. The area under the blood level-time curve of the propylene glycol-containing system was twice that of the device without propylene glycol. Blood levels were maintained between about 2 micrograms/ml and 5 micrograms/ml during the time the device was kept on the skin (24 h).

Effect of antacids on predicted steady-state cimetidine concentrations.

The purpose of this study was to evaluate effects of antacids on predicted steady-state concentrations of cimetidine. Ten healthy volunteers received in random order one week apart, cimetidine and cimetidine and antacid suspension. Blood was obtained at specified times and analyzed for cimetidine. Bioavailability was assessed by comparison of peak concentration, time to peak concentration, area under the curve, and time spent over 0.5 micrograms/ml. Single-dose data were extrapolated to steady-state using computer simulation. Concurrent administration of antacid suspension reduced parameters of bioavailability approximately 30%. When steady-state conditions were simulated, concentrations of cimetidine greater than or equal to 0.5 micrograms/ml were maintained for the entire dosing interval in seven of 10 subjects. These data suggest that temporal separation of cimetidine and antacid suspension may be unnecessary.

Interaction of digoxin with activated dimethicone and other antacid constituents.

A study was made of the effect of activated dimethicone on the absorption of digoxin in relation to other commonly used antacid constituents using an in vitro experimental model. Dimethicone was found not to affect the absorption of digoxin in relation to aluminium hydroxide, bismuth carbonate, light magnesium carbonate and magnesium trisilicate whose effects on the absorption of digoxin were in agreement with values reported in the literature.