PHP Class for sending Email and preventing Email Spam

I have created a simple PHP class that would send email and with the proper emai header format it would not be a spam email.

The following are condition to make email message not to appear as Spam emails:

1. Neader To, From, Reply-To, Cc and Bcc emails must have an existing/running domain. for example email address info@iwebprovider.com, iwebprovider.com domain must still be exist/running domain or website.

2. Inserting standard headers like MIME-Version, Content-type, To and From.

3. Subject must not have always the same content. Sample if you are sending 100 email notification they must have atleast unique subject. You could create unique subject by inserting the name of the person/company you are suppose to send your email, sample subject "Notification message to John from iWeb", "Notification message to Kate from iWeb" and etc. Sample repeated subject is "Notification message from iWeb".

interface intEmail {
	
	public function send();
	public function is_email( $email );
	public function send_mail( $send_to, $subject, $message, $headers );
	public function extract_send_to_email( $send_to_email );
	
}

class clsEmail implements intEmail {
	
	public $send = FALSE;
	public $type = NULL;
	public $charset = 'utf-8'; //iso-8859-1
	
	public $send_to = NULL;
	public $subject = NULL;
	public $headers = NULL;
	public $message = NULL;
	
	public $send_to_many = array();
	public $email_from = NULL;
	public $name_from = NULL;
	public $reply_to = NULL;
	
	public $cc = NULL;
	public $bcc = NULL;

	public function send(){
		
		$send_to = $this->send_to;
		$subject = $this->subject;
		$message = $this->message;
		if($send_to != '' && $subject != '' && $message != '' && $this->name_from != '' && $this->email_from != ''){
			if($this->type == 'html'){
				
				$send_to_email = $this->extract_send_to_email( $this->send_to );
				
				// To send HTML mail, the Content-type header must be set
				$headers  = 'MIME-Version: 1.0'."\r\n";
				$headers .= 'Content-type: text/html; charset='.$this->charset.''."\r\n";
				// Additional h	eaders
				$headers .= 'To: '.$send_to_email.''."\r\n";
				$headers .= 'From: '.$this->name_from.' <'.$this->email_from.'>'."\r\n";
				if($this->reply_to != ''){
					$headers .= 'Reply-To: '.$this->reply_to.''."\r\n";
				}
				if($this->cc != ''){
					$headers .= 'Cc: '.$this->cc.''."\r\n";
				}
				if($this->bcc != ''){
					$headers .= 'Bcc: '.$this->bcc.''."\r\n";
				}
			} else {
				$headers .= 'From: '.$this->name_from.' <'.$this->email_from.'>'."\r\n";
				if($this->reply_to != ''){
					$headers .= 'Reply-To: '.$this->reply_to.''."\r\n";
				}
				$headers .= 'X-Mailer: PHP/'.phpversion();
			}
			
			if($send_to_email != FALSE){
				
				$this->send = $this->send_mail( $send_to, $subject, $message, $headers );
				
				return $this->send;
			} else {
				//Error if no email to or wrong email to format
				return FALSE;
			}
		} else {
			//Error variable send_to, subject, message, name_from and email_from are blank.
			return FALSE;
		}
	}
	
	public function extract_send_to_email( $send_to_email ){
		
		$email_array = explode(',',str_replace(' ','',$send_to_email));
		$check_email = array();
		
		$email_name = '';
		$email_string = '';
		
		if(count($email_array) > 0){
			$cnt = 1;
			foreach($email_array as $email_value){
				if($this->is_email( $email_value ) == TRUE){
					
					$comma = $cnt > 1 ? ',' : '';
					
					$email_name_array = explode('@',$email_value);
					$email_name = $email_name_array[0];
					
					$email_string .= $comma.$email_name.' <'.$email_value.'>';
					
					$check_email[] = 1;
					
					$cnt++;
				} else {
					$check_email[] = 0;
				}
			}
			
			if(in_array(0, $check_email) == FALSE){
				
				return $email_string;
			} else {
				return FALSE;
			}
		} else {
			return FALSE;
		}
	}
	
	public function send_mail( $send_to, $subject, $message, $headers ){
		
		$mail = @mail( trim($send_to), strip_tags($subject), stripslashes($message), $headers );
		
		return $mail;
	}
	
	//Validate if proper email format
	public function is_email( $email ){
		if(preg_match("/^[^@]*@[^@]*\.[^@]*$/", $email)){
			return $email;
		} else {
			return FALSE;
		}
	}
} ?> 
  //Application of this class
   $send_to = 'to_email_1@domain.com,to_email_2@domain.com'
   $message = '
   
Hello,

   
This is a sample email

   
Thanks,

   ';
   
   $objEmail = new clsEmail();
   
   $objEmail->Email->type = 'html';
   $objEmail->Email->send_to = $send_to;
   $objEmail->Email->subject = 'Sample email';
   $objEmail->Email->name_from = 'nameofsender';
   $objEmail->Email->email_from = 'emailfrom@domain.com';
   $objEmail->Email->reply_to = 'emailfrom@domain.com';
   $objEmail->Email->cc = 'email_cc@domain.com';
   $objEmail->Email->bcc = 'email_bcc@domain.com';
   $objEmail->Email->message = $message;
   $objEmail->Email->send();