Safety and Efficacy of D-PLEX in the Prevention of Sternal Infection Post Cardiac Surgery.

Inclusion Criteria: 1. Male or non-pregnant female above 18 years old 2. Female of childbearing potential should have a negative serum pregnancy test prior to index procedure. Note: All female of childbearing potential must agree to use a highly effective method of contraception (such as double barrier, oral or parenteral hormonal, intrauterine device and spermicide) consistently and correctly for the duration of the study. 3. Subjects undergoing elective or urgent cardiac surgery, who are preoperative stable hemodynamically. 4. Subjects with (20≤BMI≤40) 5. Subjects who sign a written informed consent. Exclusion Criteria: 1. Received any investigational drug within 30 days of start of study or within 5½ half-lives (pharmacokinetic or pharmacodynamics) prior to enrollment (whichever is longer). 2. Are ineligible to receive treatment with: * Any preoperative active significant infection * Antibiotic sensitivity to Doxycycline and/or tetracycline family of drugs * Known allergies to more than 3 substances.(Patients should fill the allergy questioners during the enrolment process) * History of allergic/hypersensitivity reaction to any substance having required hospitalization and/or treatment with intra-venous steroids/epinephrine or in the opinion of the investigator the patient is at high risk of developing severe allergic / hypersensitivity reactions. * History of uncontrolled Asthma (GINA III-IV) * History of chronic urticaria 3. Pregnant or breastfeeding women. 4. Subjects who have taken oral or IV doxycycline during the last 4 weeks prior to screening. 5. Subjects who undergo cardiac/open chest surgeries, which are classified as emergency. 6. Immunocompromised subjects from any reason, at screening. 7. Subjects that undergone TIA/ CVA within the last 3 months prior to enrollment. 8. Subjects that previously underwent any cardiac surgery through mid-sternum. 9. In the opinion of investigator, subject is not eligible to participate in the study due to a cognitive status, medical condition or medication status (other than items listed above)