How to pick a chunk from the text column in postgresql
create table abc (id int primary key, name text);
insert into abc values 
(1, 'Verapamil 160mg tablets (X Y Z Pharmaceuticals Ltd) **56 tablet** 4 x 14 tablets'),
(2, 'Zocor 10mg tablets (You &amp; Me Ltd) **28 tablet** 2 x 14 tablets'),
(3, 'Atenolol 100mg tablets (NoName Pharmaceuticals Ltd) **20 tablet** 2 x 10 tablets');

If there is a pattern, for example: (1 or more digits) plus the word tablet, you can use a regular expression like this:
select 
    substring(name, '([0-9]+ tablet)')
from
    abc;



| substring |
| :-------- |
| 56 tablet |
| 28 tablet |
| 20 tablet |


db&lt;&gt;fiddle here