Medical reimbursement payment time frame

Dear Sir,

I want to know, Is there any  Payment time frame for Medical Claim/Reimburement to employee, i.e. If an employee submit medical claim/reimbursement for Arpil in August, can it be reimbursed??? Is there any such rule there or any anybody can claim reimbursement at any point of time irrespective of month and take the reimbursement?? Kindly suggest ..........