Interactions
Interactions of MGA include significantly decreased exposure to indinavir, which may necessitate an increased dosage of the medication. When MGA is co-administered with zidovudine and rifabutin, there is no significant change in exposure to these medications and no dosage adjustment is necessary. Pharmacology
Pharmacodynamics
MGA has progestogenic activity, antigonadotropic effects, weak partial androgenic activity, and weak glucocorticoid activity. Progestogenic activity
MGA is a progestogen, or an agonist of the progesterone receptor (PR). It has about 65% of the affinity of promegestone and 130% of the affinity of progesterone for the PR. Like other progestogens, MGA has functional antiestrogenic effects in certain tissues such as the endometrium and has antigonadotropic effects. The total endometrial transformation dose of MGA is 50 mg per cycle. Antigonadotropic and anticorticotropic effects
MGA has antigonadotropic effects in humans at sufficient doses, capable of profoundly suppressing circulating androgen and estrogen concentrations. The antigonadotropic effects of MGA are the result of activation of the PR, which suppresses the secretion of the gonadotropins—peptide hormones responsible for signaling the body to produce not only progesterone but also the androgens and the estrogens—from the pituitary gland as a form of negative feedback inhibition, and hence downregulates the hypothalamic–pituitary–gonadal axis (HPG axis), resulting in decreased levels of the sex hormones and interference with fertility. As such, MGA has functional antiandrogenic and antiestrogenic effects as well as contraceptive effects via its antigonadotropic effects.The precise ovulation-inhibiting dosage of MGA is unknown.
A perforation is a small hole in a thin material or web. There is usually more than one perforation in an organized fashion, where all of the holes collectively are called a perforation. The process of creating perforations is called perforating, which involves puncturing the workpiece with a tool. Perforations are usually used to allow easy separation of two sections of the material, such as allowing paper to be torn easily along the line. Packaging with perforations in paperboard or plastic film is easy for consumers to open. Other purposes include filtrating fluids, sound deadening, allowing light or fluids to pass through, and to create an aesthetic design.Various applications include plastic films to allow the packages to breathe, medical films, micro perforated plate and sound and vapor barriers. Processes
Pins and needles
Rotary pinned perforation rollers are precision tools that can be used to perforate a wide variety of materials. The pins or needles can be used cold or heated. Cold perforation tools include needle punches. There are a handful of manufacturers that specialize in hot and cold needle perforation tooling and equipment. In materials that have elasticity this can result in a "volcano" hole that is preferred in many applications. Pinned rollers can be made from a variety of materials, including plastic, steel, and aluminum. In more brittle films, cold perforation can cause slitting rather than creating a round hole, which can jeopardize the materials integrity under pressure. The solution to this is often heating the pin; i.e. hot pin perforation.