var1='Value 1' and var2='Value 2'
.var1='Value1' and var2='Value2'
.$str = <<<'DOC'
var1='Value 1' and var2='Value 2'
var1='Value 1 a' and var2='2 b'
var1=' 1a ' and var2='2b'
var1='Value 1 2 3 abc 4'
DOC;
echo preg_replace_callback("/'[^']+'/", function($value) {
return str_replace(' ', '', $value[0]);
}, $str);
// var1='Value1' and var2='Value2'
// var1='Value1a' and var2='2b'
// var1='1a' and var2='2b'
// var1='Value123abc4'