$re = '/[\u006E\u00B0\u00B2\u00B3\u00B9\u02AF\u0670\u0711\u2121\u213B\u2207\u29B5\uFC5B-\uFC5D\uFC63\uFC90\uFCD9\u2070\u2071\u2074-\u208E\u2090-\u209C\u0345\u0656\u17D2\u1D62-\u1D6A\u2A27\u2C7C]+/';
$str = 'ᵀᴹ ¹²³ ⁰⁴Txtͅ ٖ ្ ᵢ ᵣ ᵤ ᵥ ᵦ ᵧ ᵨ ᵩ ᵪ ₀ ₁ ₂ ₃ ₄ ₅ ₆ ₇ ₈ ₉ ₊ ₋ ₌ ₍ ₎ ₐ ₑ ₒ ₓ ₔ ₕ ₖ ₗ ₘ ₙ ₚ ₛ ₜ ⨧ ⱼ n ° ² ³ ¹ ʯ ٰ ܑ ⁰ ⁱ ⁴ ⁵ ⁶ ⁷ ⁸ ⁹ ⁺ ⁻ ⁼ ⁽ ⁾ ⁿ ℡ ℻ ∇ ⦵ ﱛ ﱜ ﱝ ﱣ ﲐ ﳙ ';
$subst = "";
$result = preg_replace($re, $subst, $str);
echo "The result of the substitution is ".$result;
Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for PHP, please visit: http://php.net/manual/en/ref.pcre.php