Variable Pivot Gait Based a Novel Dynamics Correction Method for Human Lower Limbs Model.

The rationality of gait analysis directly affects the dynamics of human lower limbs in the sagittal plane, and recent studies on gait stage redivision lack the stage when both feet are not in complete contact with the ground. This paper proposes a novel variable pivot gait, which includes the stage when the heel of one foot and the toe of the other are in contact with the ground and a dynamics correction method based on this gait. First, the relative motion data between the foot and the ground are measured by motion capture experiments, and then a variable pivot gait is proposed in terms of the pivot transformation between the foot and the ground. Second, the dynamics modeling is conducted based on the principle of mechanisms of human lower limbs in each stage of the variable pivot gait. Third, a dynamics correction method is proposed to correct the foot dynamics when the foot is not in complete contact with the ground. The experiment and simulation show that the variable pivot gait is consistent with the actual motion of the foot relative to the ground. The effectiveness of the dynamics correction method is proved by comparing dynamics results (hip, knee, and ankle moments) with previous studies. The variable pivot gait and the dynamics correction method can be applied to the human lower limbs and lower-limb robots, providing a new avenue.

A novel spray-dried nanoparticles-in-microparticles system for formulating scopolamine hydrobromide into orally disintegrating tablets.

Scopolamine hydrobromide (SH)-loaded microparticles were prepared from a colloidal fluid containing ionotropic-gelated chitosan nanoparticles using a spray-drying method. The spray-dried microparticles were then formulated into orally disintegrating tablets (ODTs) using a wet granulation tablet formation process. A drug entrapment efficiency of about 90% (w/w) and loading capacity of 20% (w/w) were achieved for the microparticles, which ranged from 2 µm to 8 µm in diameter. Results of disintegration tests showed that the formulated ODTs could be completely dissolved within 45 seconds. Drug dissolution profiles suggested that SH is released more slowly from tablets made using the microencapsulation process compared with tablets containing SH that is free or in the form of nanoparticles. The time it took for 90% of the drug to be released increased significantly from 3 minutes for conventional ODTs to 90 minutes for ODTs with crosslinked microparticles. Compared with ODTs made with noncrosslinked microparticles, it was thus possible to achieve an even lower drug release rate using tablets with appropriate chitosan crosslinking. Results obtained indicate that the development of new ODTs designed with crosslinked microparticles might be a rational way to overcome the unwanted taste of conventional ODTs and the side effects related to SH's intrinsic characteristics.