The data show substantially greater exposure to tizanidine from the oral spray (OS) formulations and earlier detectable plasma drug levels for OS doses versus the tablet (approximately 10 minutes and 17 minutes respectively, where p values ranged from 0.0002 to 0.0117). When dose normalized (to 4mg), the bioavailability of the tizanidine OS doses were 2.04 to 3.49-fold greater than that of the 4mg tablet.
The 2mg oral spray and 4mg tablet doses gave comparable results in the Digit Symbol Substitution Test (DSST) test where positive scores were observed compared to baseline. There was an apparent decrease in the DSST scores after administration of the 4mg and 8mg OS study drugs. A decrease in the DSST score indicates a decrease in attention, perceptual speed, motor speed, visual processing and memory. These results indicate that tizanidine OS is a well tolerated and safe based on the relatively small number of reported adverse events and the absence of any serious adverse events both locally and systemically.
Tizanidine is a leading drug indicated for the management of spasticity. This study demonstrates drug delivery across the oral mucosa, achieving faster entry of drug into the bloodstream with greater bioavailability and importantly in this particular disorder, avoiding the need to swallow a tablet or capsule.