foreach loops: wildcard asterisks (*), nested macros, string variables - resolving errors when using * - foreach

Question

In Stata, in a foreach loop, I am searching for values within string variables, using strmatch() and asterisk (*) wildcards. I need the asterisks because I'm searching for words that fall into any part of the string.
These string variables are nested into local macros. However using * in the foreach does not work with Stata IF it is part of a nested/descendant macro. Is this because:
A) wildcards within strings can never be used in foreach in Stata when using nested macros, or
B) it isn't the wildcard itself, but the * (asterisk) that is producing the error in foreach?
If B), is it possible to define a new character that means 'wildcard' instead of * so I can still use nested macros to organize my concepts before doing foreach?
Note: I'm working with a large dataset so the strmatch() function without the foreach loop is not a solution, unless there is an alternative to foreach.
Here's an example, for drug class Q (parent/ancestor macro), with individual drug lists (descendant macro):
*chem term list
local drug_list1 " "A*B" "B*A" "A" "
local drug_list2 " "C*D" "D" "
*search term list
local drugclassQ " "drug_list1" "drug_list2" "
*check macro data successfully stored
di `drugclassQ'
(successfully stored)
*Search all drug terms in descriptions
foreach searchterm in "drugclassQ" {
gen byte `searchterm' = 0
di "Making column called `searchterm'"
foreach chemterm in ``searchterm'' {
di "Checking individual search terms in: `chemterm'"
foreach indiv in ``chemterm'' {
di "Searching all columns for *`indiv'*"
foreach codeterm in lower(variable) {
di "`searchterm': Checking `codeterm' column for *`indiv'*"
replace `searchterm' = 1 if strmatch(`codeterm', "*`indiv'*")
}
}
}
}
gen keep_term = .
replace keep_term=1 if drugclassQ==1
keep if keep_term==1
Here's an example of what I would want the foreach loop for find, searching within the string variable chemical
For example searching on "A*B" within parent macro drugclassQ would find drugs with string values within the string variable chemical as the following:
Amg / Fmg /B A/B A/ B/R Amg/dose / Emg/dose / Bmg/dose
(note: mg = milligrams to illustrate my point about needing to define the variable as a string since the drugs are entered into the database in different ways)
Example Output to identify strings with A and B anywhere within values of 'Chemical':
Obs
Chemical (string variable)
drugclassQ
1
Amg / Fmg /B
1
2
A/B
1
3
A/ B/R
1
4
Amg/dose / Emg/dose / Bmg/dose
1
5
A
0
My code works when I don't use asterisks, but then that defeats the premise of how I'm using the foreach code, i.e. using the wildcard that is within nested macros.
Any solutions?