22 Tex. Admin. Code § 169.3
A physician may personally administer those drugs to his or her patients, which are, in the physician's medical judgment, therapeutically beneficial or necessary for the patient's treatment. A physician may delegate to any qualified and properly trained person the authority to administer drugs. A physician shall comply with all appropriate record keeping requirements applicable to the drugs administered, or shall assure compliance with said record keeping requirements by persons acting under the physician's direction and supervision. A physician may charge a fee for the administration of drugs to a patient that is separate from fees charged for other medical services. The separate fee shall allow the physician to recover the cost of administration, including the cost of the drug itself.
22 Tex. Admin. Code § 169.3