Drug solubility vaginal

Some studies in the pharmaceutical area used a common protocol, adapting it to the specific properties of the drug (solubility and wavelength). A certain quantity of the microparticles is suspended in a given volume of solution (distilled water, buffer pH 1.2, buffer pH 7.4, phosphate buffer pH 7.2, simulated vaginal fluid). The sample is then heated (in some case, 2°C above the melting... 

The absorption of drugs from the rectal [32] cavity has been studied in some detail. Muranishi et al. [34] have shown that a significant increase in the absorption and lymphatic uptake of soluble and colloidal macromolecules can be achieved by pretreating the rectal mucosal membrane with lipid-nonionic surfactant mixed micelles. They found no evidence of serious damage of the mucosal membrane. Davis [30] suggested that the vaginal cavity could be an effective delivery site for certain pharmaceuticals, such as calcitonin, used for the treatment of postmenopausal osteoporosis. 

For a vaginally administered drug to exert a local or systemic effect, it must possess at least some degree of solubility in vaginal fluid. It is therefore important to consider the nature of vaginal fluid and, in particular, the characteristics of vaginal fluid that may effect vaginal absorption. 

The increase in vaginal fluids due to estrogens and sexual stimulations improve the absorption of poorly water-soluble drugs on the contrary, a greater presence of mucus on the mucosal membrane slows down the contact between the drug and the absorptive epithelium [3]. Moreover, the vaginal fluids could remove and wash away the formulations from application and action site or cause an erratic drug distribution. Furthermore pH variation,... 

The nonperoral mucosal delivery routes such as buccal, nasal, and vaginal sites offer barriers to drug molecules similar to that of the peroral route. Drugs delivered via these routes have to be small (<300 Da), lipophilic in nature, and with low dosage regimen requirements. The different approaches used to deliver drugs across these mucosae include the use of enzyme inhibitors, penetration enhancers, bioadhesive patches, prodrugs, liposomes, and solubility modifiers.96,106,130... 

Also, gel microemulsions have been recently reported as safe and devoid of mucosal toxicity drug delivery systems, presenting intrinsic spermicide activity and the possibility of improving vaginal bioavailability of poorly soluble antimicrobial agents [100],... 

The incorporation of drug-loaded liposomes in adequate formulations can improve their stability, allowing their applicability in vaginal drug delivery [151], Additionally, entrapment of drugs in liposomes may improve their solubility and... 

Nystatin was discovered in 1950 and exhibits the same mode of action as amphotericin B but tends to be of lower solubility, which has restricted its use to the treatment of topical infections. While nystatin was effective for the treatment of conditions such as oral and vaginal candidosis its use has been overtaken by the introduction of azole antifungal drugs. 

Trimethoprim is the only weak base listed (fluoroquinolones and sulfonamides are acidic compounds), and its high lipid solubility at blood pH allows penetration of the drug into prostatic and vaginal fluid to reach levels similar to those in plasma. Leukopenia and thrombocytopenia may occur in folate deficiency when the drug is used alone or in combination with sulfamethoxazole. Fluoroquinolones do not exacerbate symptoms of folic acid deficiency. The answer is (D). 

N. Shelke, J. Clark, T. Johnson, J. Fabian, A. Tuitupou, J. Nebeker, M. Clark, D. Friend, P. Kiser, 90 Day vaginal delivery of poorly water soluble drug levonorgestrel from coaxially extruded polyurethane reservoirs, in Utah Biomedical Engineering Conference Rice Eccles Stadium, Salt Lake City, Utah, USA, 2011. 

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