Sex Transm Infect 76:480-483 doi:10.1136/sti.76.6.480

Preliminary safety and acceptability of a carrageenan gel for possible use as a vaginal microbicide

  1. C Coggins1,
  2. K Blanchard1,
  3. F Alvarez2,
  4. V Brache2,
  5. E Weisberg3,
  6. P H Kilmarx4,
  7. M Lacarra5,
  8. R Massai6,
  9. D Mishell, Jr5,
  10. A Salvatierra6,
  11. P Witwatwongwana7,
  12. C Elias8,
  13. C Ellertson1
  1. 1The Population Council, New York, USA
  2. 2Asociacion Dominicana Pro-Bienestar de la Familia, Santo Domingo, Dominican Republic
  3. 3Sydney Centre for Reproductive Health Research, Department of Obstetrics and Gynaecology, University of Sydney, Sydney, Australia
  4. 4Centers for Disease Control and Prevention, Atlanta, USA; The HIV/AIDS Collaboration, Chiang Rai, Thailand
  5. 5University of Southern California, Los Angeles, USA
  6. 6Instituto Chileno de Medicina Reproductiva, Santiago, Chile
  7. 7Chiang Rai Hospital, Chiang Rai, Thailand
  8. 8The Population Council, Bangkok, Thailand
  1. Kelly Blanchard, Population Council, One Dag Hammarskjold Plaza, New York, NY 10017, USA kblanchard{at}
  • Accepted 18 July 2000


Objective: We sought to determine the safety and acceptability of vaginal gel formulation PC-503 among low risk, abstinent women. The active ingredient was 2% pharmaceutical grade lambda carrageenan, a sulphated polymer that is generally recognised as safe by the US Food and Drug Administration.

Methods: 35 women in five sites applied 5 ml of the PC-503 gel vaginally once a day for 7 days while abstaining from sexual intercourse. Visual vaginal examinations were performed on days 1, 4, and 8. STI testing and vaginal pool Gram stain preparations were done on days 1 and 8. Participants were asked about product acceptability.

Results: 34 of the 35 women enrolled completed 7 days' use. Following product use, five reported mild symptoms including “bladder fullness,” “genital warmth,” or discomfort, and lower abdominal pain, and one had moderate pale yellow cervical discharge. Using the Nugent criteria, three women had bacterial vaginosis (BV) before and after use; three had BV before but not after, and two had BV after but not before. Most of the women found PC-503 to be pleasant or neutral in feel and smell and considered extra lubrication to be an advantage; however, one third found it to be messy.

Conclusions: Vaginal use of PC-503 gel did not cause significant adverse effects in a small number of low risk, sexually abstinent women. Further testing in larger numbers of sexually active women is planned. A smaller volume of gel may be more acceptable to some women.