Vaginal Drug Delivery Flashcards
(22 cards)
What is the role of the resident bacteria in the vagina, and what do they produce?
The resident bacteria, mainly lactobacilli, maintain a vaginal pH of 4-4.5 by fermenting glycogen secreted from the vaginal epithelium to lactic acid.
How does the normal vaginal flora provide protection?
By producing hydrogen peroxide and antimicrobial peptides, preventing colonization by pathogenic organisms.
What factors can affect the vaginal flora?
Vaginal douching, antibiotics, a weakened immune system, hormonal fluctuations, and alkaline body fluids (e.g., blood during menstruation, semen during copulation) can transiently increase vaginal pH.
What is the role of lactobacilli in the vagina?
Lactobacilli maintain a pH below 4.4, preventing pathogen growth.
What makes the vagina an effective route for drug delivery?
The vagina’s blood vessels
What are the key features of vaginal drug delivery systems?
Ease of administration, self-administration, predictable bioavailability, systemic or local delivery, avoidance of hepatic first-pass effect, minimal interference with other medications or body functions.
What is the main challenge with vaginal drug absorption?
Poor absorption across the vaginal epithelium.
What are some examples of active pharmaceutical ingredients delivered through the vagina?
Sex hormones (contraception, HRT), prostaglandins, clotrimazole (antifungal), lactic acid (pH adjustment), clindamycin (antibacterial), metronidazole (antibacterial).
What physicochemical properties affect drug absorption in the vagina?
Lipophilic, low molecular weight drugs are more likely to be absorbed than hydrophilic, high molecular weight drugs.
How do hormonal changes during the menstrual cycle influence drug absorption in the vagina?
Hormonal changes affect epithelial thickness, permeability, pH, secretion, and enzyme activity, all of which influence drug absorption.
How does the vaginal microflora affect drug absorption?
The vaginal microflora, primarily Lactobacillus, must be considered as it can be influenced by factors like glycogen and glucose content.
How does vaginal fluid affect drug absorption?
The amount and nature of vaginal fluid affect drug dissolution and absorption, but excessive fluid loss may carry away the drug or delivery system.
What role does cervical mucus play in drug absorption?
Cervical mucus composition can aid microparticle adhesion but may also act as a barrier to drug diffusion.
What are the key features of semi-solid vaginal drug delivery preparations?
They should be easy to use, non-toxic, non-irritating, and can be emulsion-based or hydrogel-based. Hydrogels release drugs in a controlled manner.
What is the purpose of vaginal pessaries and tablets?
Pessaries melt in the vaginal cavity to release drugs over hours (e.g., cervical ripening, hormonal replacement).
Vaginal tablets are easy to insert and manufacture, used for drugs like clotrimazole, itraconazole, and prostaglandins.
What is the function of hydrogels in vaginal drug delivery?
Hydrogels are hydrophilic polymers that release drugs in a controlled manner, such as miconazole (antifungal cream).
What types of drugs are typically administered via vaginal pessaries?
Drugs like dehydro-epiandrosterone sulphate (for cervical ripening) and progesterone (for hormonal replacement).
What is the purpose of vaginal tablets in drug delivery?
Vaginal tablets are easy to insert and manufacture. They are used for delivering drugs like clotrimazole (antifungal), itraconazole (antifungal), and prostaglandins
What are vaginal rings, and how do they function?
Vaginal rings are circular ring-type dosage forms that release drugs in a controlled manner after vaginal insertion. They are around 5.5 cm in diameter, with a cross-sectional diameter of 4-9 mm. The active drug is uniformly dispersed within the polymeric ring.
Which types of polymers are used in bio adhesive vaginal delivery systems?
Polymers include hydroxypropyl cellulose, polycarbophil, polyacrylic acid derivatives, chitosan, pectin, tragacanth, and starch. Hydrophobic polymers like ethylcellulose lack bio adhesivity.
What is the role of hyaluronic acid-based vaginal systems?
Hyaluronic acid-based systems deliver peptide drugs such as calcitonin for postmenopausal osteoporosis.
What is the goal of vaginal immunization?
Vaginal immunization aims to achieve mucosal and systemic immunity. Several vaginal vaccine formulations have been developed against pathogens like HIV.
