Лако-красочные материалы — производство

The vaginal and cervical route of administration is unique from other routes in that the tissue environment is subject to many changes throughout a women’s life. Depending on whether the woman is pre — or postmenopausal, the tissue and mucus of the vaginal and cervical areas can be vastly different. Decreased endogenous levels of estrogen, cervical shrinkage, cell atrophy, and lower cervical mucus levels [66] are characteristic of postme­nopausal women. Thus a vaginal bioadhesive delivery system geared to older women would need to address these conditions to optimize drug availability.

A women’s menstrual cycle can also affect the vaginal environment. Vaginal mucus originates in the cervix, then migrates into the vaginal area. Monthly fluctuations in the properties of cervical mucin have been documented [67], showing lower viscoelasticity when estrogen is dominant and thicker, more viscoelastic mucin when progesterone dom­inates. Again, a bioadhesive delivery system must take these considerations into account to optimize the bioavailability of drug to the tissue.

Most vaginally administered drugs ware delivered via creams, foams, suppositories, gels, or tablets. The women’s health care market is very large and profitable and hence a number of delivery systems utilizing bioadhesives have started to appear. The patented use of a soluble hydroxypropyl cellulose (HPC) cartridge for vaginal delivery of drugs has been shown to release the drug for an extended period of time [68]. The polymer forms a hydrated gel of sufficient viscosity in the vaginal cavity and releases the drug directly to the vaginal area. The anticancer drugs bleomycin, carbazilquinone, and 5-fluorouracil have been administered directly to the cervix using disk — and rod-shaped dosage forms containing a combination of HPC and Carbopol [69,70]. These dosage forms were shown to stay in the diseased area for a longer period of time than vaginal suppo­sitories containing the same drug. Compared to suppositories, local side effects of these dosage forms were also reduced. Such a system has the possibility, then, to treat cancer of the cervix locally.

During a woman’s reproductive years, the vaginal bacterial flora is capable of main­taining an acidic environment which can reduce vaginal infection by limiting the bacterial growth often associated with other disease states [71]. Maintenance of this slightly acidic pH is then crucial for vaginal health, and thus drug delivery systems that address this phenomenon have obvious therapeutic benefits. A vaginal moisturizer containing the bioadhesive polycarbophil has been shown to alleviate postmenopausal vaginal dryness (Replens, Columbia Laboratories, Hollywood, Florida). The cream has the ability to remain in the vaginal cavity for 2 to 3 days after only one administration and maintains a healthier vaginal environment through its hydration of the mucosa. Because of poly — carbophil’s pKa value of 4.75, the cream also can maintain a nearly normal acidic vaginal pH, which, as discussed above, has certain health-related advantages.