Where the experts come to work

Since 2011, we’ve been serving our community and the clinical research industry. When you work with the best people, you receive the best care.

Meet Our Physicians / Investigators

Timothy Grant, MD, FAASM

Medical Director

Dr. Timothy Grant, the medical director of the Neurology and Sleep Medicine Divisions at CenExel RCA. Dr. Grant is a board-certified neurologist and sleep specialist, he is widely recognized for his work in neurology and expertise in sleep medicine.

Maria DePombo, MD

Principal Investigator

Dr. Maria DePombo is a Board Certified Psychiatrist who joined CenExel RCA in 2018 where she serves as a Principal and Sub-investigator. Her areas of research focus on patients suffering from Depression, Bipolar, Schizophrenia and substance disorders.

Nelson Cordero-Torres, MD

Principal Investigator

Dr. Cordero has delved into clinical research since starting withCenExel RCA and is currently one of RCA’s Principal Investigators. He has experience with over 50 clinical trials and always maintains abreast on current research in CNS. Dr. Cordero’s experience and leadership pave the way for success in conducting clinical trials atCenExel RCA.

Sandeep Mendiratta, MD

Principal Investigator

Dr. Mendiratta has gained experience in clinical research since beginning his career as a psychiatrist. Dr. Mendiratta has served as sub-investigator for the majority ofCenExel RCA’s clinical trials in both the outpatient and inpatient settings for a variety of diagnoses including schizophrenia, ADHD, substance abuse and depression. His expertise in these areas have led to several features in Broward Health’s Monthly Magazine and local television newscasts.

Nelia Sanchez-Crespo, MD

Principal Investigator

Dr. Nelia Sanchez-Crespo is an Internal Medicine Physician graduated Cum Laude from PUCMM in Dominican Republic and completed specialty training in United States at Atlanta Medical Center with high honors. She is Board Certified in Internal Medicine. Dr. Sanchez-Crespo has continued experience thru over 15 years of medical practice. She is an investigator in multiple clinical trials atCenExel RCA and she secures patient care through the research operation. She is fluent in English and Spanish.

Americo Padilla, MD


Dr. Padilla is the Chief of Psychiatry at Nicklaus Children’s Hospital. His experience includes Directorship of several psychiatric units throughout the city of Miami. Currently, he is conducting numerous researches in the child psychiatric area. He is board certified by The American Board of Neurology and Psychiatry in both Adult and Child, Adolescent Psychiatry.

Barbara Corral

Director of Operations & Sub Investigator

Barbara Corral is the Director of Operations and serves as a Sub-Investigator for Research Centers of America. She is a well-rounded Nurse Practitioner with extensive experience in emergency, adult, pediatric and psychiatric medicine. She has practiced in various settings including hospitals and private practices. Additionally, she has worked on both inpatient and outpatient clinical trials and has over five years of experience working with Acute and Chronic Illnesses.

Barbara graduated Magna Cum Laude from her Master’s of Science in Nursing. She is a highly dedicated, caring, and hardworking clinician.

Surisaday Mederos


Surisaday Mederos serves as a Sub-Investigator and director of operations at the south office for CenExel RCA. She is a Board-Certified Family Nurse Practitioner and a Certified Clinical Research Coordinator. Suri has over 15 years of experience as a clinical research coordinator and worked on multiple clinical trials in both the inpatient and outpatient setting.

She has practiced in various health settings including, hospitals and private practices. Additionally, Suri has over two years of experience working as a provider for a neurology practice focused on sleep medicine.

Surisaday’s passion is to advocate for her patients and practice using the best evidence available in order to promote and prioritize safety. In addition, she loves to spend time with her family and two children.

Jennifer Schwartz

Jennifer Schwartz

Board-certified Family Nurse Practitioner

Jennifer Schwartz received her Bachelor’s of Science in Nursing from the University of Michigan, and then furthered her education at the University of Miami, where she received a Master’s of Science in Nursing.

As a Family Nurse Practitioner, she worked in an endocrinology practice treating hormonal imbalances and providing nutrition and diabetes counseling. She became a Certified Diabetes Educator (CDE) to further enhance this skill set. She continued her career at Village Park Medical where she practiced in internal medicine and infectious disease.

Jennifer has a profound interest in medical research. Over the last ten years, she worked as a research coordinator, then a registered nurse in a Phase I unit, and now as a Nurse Practitioner for Phase I, II, and III clinical trials. Jennifer enjoys living in Miami, spending time with her family and staying active with tennis and yoga.

Janet Tamayo

Janet Sentil Tamayo

Board-certified Nurse Practitioner

Janet graduated from Miami Regional University. Professional experience as registered nurse in medical-surgical and telemetry units for Mount Sinai medical center and Memorial hospital Miramar. Professional experience as primary care physician in Havana, Cuba. Highly loyal, team player, with a steadfast commitment to quality care and preventative care advocacy. Disciplined, and confident. Speaks both English and Spanish.

Inna Ozerov, MD


Dr. Inna Ozerov is a Sub-Investigator at CenExel RCA. She is a Diplomate of the American Board of Ophthalmology and specializes in the diagnosis and treatment of medical and surgical corneal diseases, with a particular interest in the treatment of Keratoconus and Dry Eye Syndrome.

Elizabeth Etkin-Kramer, MD


Dr. Etkin-Kramer holds various leadership and educator roles in South Florida. She is the Past President of the Dade County Medical Association (2012-2013) and is currently an officer in the Florida District XII of the American College of Obstetrics and Gynecology . She is a clinical instructor in gynecology for the Miami Dade College Physician Assistant program and holds a voluntary role as assistant professor of obstetrics and gynecology at both the University of Miami’s Leonard P. Miller School of Medicine and Florida International University School of Medicine. In addition, she is the medical director of South Florida Research Associates.
Monifa Wilson-Morris

Monifa Wilson-Morris, MBBS, MPH

Project Manager

Monifa serves as the Project Manager for the Vaccine Division and oversees all vaccine trials from start-up through to completion. Prior to joining RCA, Monifa graduated from the University of the West Indies with a Bachelor of Medicine and Surgery and practiced as Medical doctor in Jamaica for more than 15 years. She completed a Postgraduate training and practiced as an OBGYN for several years in various settings. Monifa received a Dean Scholarship and completed a Master of Public Health at Johns Hopkins University with an emphasis on Maternal Health. At RCA she has worked on multiple clinical trials as a Senior Research Coordinator with a focus on Vaccine trials for Phase I, II, and III clinical trials.
May Fernandez

Mayra (May) Fernandez

Director of Operations

May operates and assumes responsibility as the head of site management and monitors the entire process of Phases I through Phase III of clinical trials. May oversees and directs close to 150 employees and helps to plan, guide and problem-solve clinical research studies across all RCA locations. By facilitating and supporting all studies start-up activities, May is responsible for collaboration efforts with cross functional internal and external teams to successfully conduct trials on schedule, on budget, in compliance, and to the highest quality standards.

May has excellent organizational, analytical, and project management skills. Leading by example and being very passionate about coaching her team to meet and exceed the business goals is what May brings every day to our organization.

Katherine Ali

Katherine Ali

Call Center Manager

She has 8+ years’ experience with Call Centers/Customer Service as well as development of Call Centers. Katherine and her team help provide top quality customer service. Her focus has primarily been on the pandemic, recruitment for COVID vaccines. Being transparent and communicating thoroughly is key. She is very passionate about helping her team succeed beyond expectations and the wellbeing of her patients.

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