The amount of any loan to a qualified person shall be determined according to regulations promulgated by the Student Loan Authority. No payment shall be made to any qualified person until he has executed a note, insured by the United States and payable to a fund which shall be created to be known as the “Student Loan Sinking Fund”, for the full amount of the loan and interest thereon. For the purpose of the Oklahoma Student Loan Act, Section 695.1 et seq. of this title, a qualified person has the capacity to contract and is bound by any contract executed by him; the defense that he was a minor at the time he executed a note is not available to him in any action arising on his note. Payments to qualified persons executing notes may be made annually, semiannually, or for each semester as determined by the Authority. The rate of interest charged the student shall not exceed the maximum authorized by federal regulations. Disbursements may be made to a participating institution pursuant to a contract between the Authority and the participating institution executed under the Oklahoma Student Loan Act.