Reading text file into pandas which contains escape characters results in missing data

Question

I have a long list of regex patters that I want replace with in some text data, so I created a text file with all the regex patterns and the replacements I want for them, however, when reading this text file as a pandas dataframe, one particular regex pattern is missing in the dataframe. I tried to read it as a text file instead and build a pandas dataframe out of it but since some of the regex patterns contain "," in them, it becomes difficult to separate each line as 2 different columns.

the key(regex_pattern), value(the values I want to replace them with look as follows):

key,value
"\bnan\b|\bnone\b"," "
"^\."," "
"\s+"," "
"\.+","."
"-+","-"
"\(\)"," "

when I read this as a dataframe using the following lines of code,

normalization_mapper = pd.read_csv(f"{os.getcwd()}/normalize_dict.txt", sep=",")

I also tried the datatype argument as follows

dtype={'key':'string', 'value':'string'}

what I can't figure out is how to handle this "\(\)" missing pattern in the dataframe, pretty sure it's related to the escape character formatting by the pandas data reader, is there a way to handle this? Also, weirdly escape characters in other rows have no issues when reading the text file.