The past decade has seen several effective anti-HIV-1 agent discoveries, yet microbicides continue to disappoint clinically. Our review expounds the view that unsatisfactory microbicide failures may be a result of inefficient delivery systems employed.
Microbicide delivery devices will be critical in ensuring safe and effective use of microbicide products. The device impacts the product’s overall safety (relationship with product purity and stability, avoidance of local trauma associated with insertion or use), efficacy (consistent delivery of the required amount of product in the intended location), and acceptability (comfort, ease of use, disposability).
Several novel microbicide delivery methods to help reduce cost, ensure microbicide efficacy, and increase user acceptability. Methods include:
• Diaphragm: This combination of barrier method and microbicide could enable prevention of both pregnancy and disease. Two studies were recently completed. One study assessed gel retention and distribution in the vagina comparing Diaphragm single-sided and double-sided gel delivery to a
vaginal applicator. The second study used the same three gel application modes and evaluated couples’ use acceptability.
• Paper applicator with dosage stop: This user-filled applicator is low cost, easily disposed of, and prevents over-filling, making it an important option for microbicide gel delivery in low-resource settings.
• Rectal applicator: This applicator has been designed specifically for the rectal delivery of microbicide products.
Intravaginal targeting of HIV-1 increases the chances of microbicide success, wherein vaginal micro environmental factors including pH should be maintained at HIV-1 prohibitive acidic levels simultaneously to ward off other sexually transmitted diseases, which compromise vaginal epithelial barrier properties.
Furthermore, choice of receptors to target both on HIV-1 and on target cells is vital in deterring transmission. Appropriate modeling of virus–target cell interactions as well as targeting early stages of the HIV-1 infection accompanied by computation and delivery of appropriate microbicide quantities could revolutionize microbicide research, ultimately delivering a female-controlled HIV-1 prevention modality appropriately.
(Qualitative and quantitative intravaginal targeting: Key to anti-HIV-1 microbicide delivery from test tube to In Vivo success; Viness Pillay,*, Felix Mashingaidze, Yahya E. Choonara, Lisa C. Du Toit, Eckhart Buchmann, Vinesh Maharaj, Valence M. K. Ndesendo, Pradeep Kumar)
