Ultra low power with biomedical frequency low-pass filters has many applications in biomedical signal processing unit. Biomedical signals are usually in the 10mHz to 100Hz frequency range and hence require sub hertz frequency filters to condition to the signal before processing the performance of passive filters degrades at the high frequencies and the required values of resistance and inductance and very difficult to meet from the market. To find a solution to this problem is to study active filters using Operational Transconductance Amplifier (OTA). The aim of this work to determine the values of design parameters that optimize an objective feature where as satisfying specifications or constraints. This fourth order filter is implemented in a 0.18µm technology in terms of power consumption and cutoff frequency this filter performs better than previous filter from the literature. This circuit is used with low frequency signal low power portable medical equipment