Active Ingredients: Doxycycline
Non-provisional patent application Ser.
Provisional Patent Application No. It can also be re-absorbed in the renal tubules and gastrointestinal tract due to its high lipophillicity so has a long elimination half life, and does not accumulate in the kidneys of patients with kidney failure due to the compensatory excretion in faeces.
It inhibits the synthesis of bacterial proteins by binding to the 30 S ribosomal subunit, which is only found in bacteria. This stops bacterial growth giving the immune system time to kill and remove the bacteria.
American Cyanamid was one of these, and in the late 1940 s chemists there discovered chlortetracycline, the first member of the tetracycline class of antibiotics.
Both compounds, like penicillin, were natural products and it was commonly believed that nature had perfected them, and further chemical changes could only degrade their effectiveness.
It is therefore desirable to provide a drug delivery system utilizing electrospun polymer fibers. It is also desirable to provide a system and method for preloading drugs in the delivery system in a manner that allows the delivery system to be stored for an extended period of time.
The fibers and the improved contact lens provide a drug delivery system comprising a drug-releasing scaffold formed from a mat of electrospun fibers and methods for incorporating various therapeutic drugs into the mat.
Various processes for treating the electrospun mats after loading with therapeutic drugs are also described for improving the drug delivery characteristics, such as coating the mats in a polymer and cross-linking the electrospun fibers.
The improved contact lens described herein also comprises a contact lens that incorporates electrospun fibers to provide desirable physical characteristics.
The thinner cross-section lens provides increased oxygen permeability while maintaining mechanical strength.
The electrospinning process typically comprises an apparatus including one or more electrically-conducting liquid dispenser, such as a stainless steel needle, disposed adjacent to a collector.
The liquid dispenser is held at a high electric potential, or voltage, with respect to the collector. The polymer solution is propelled through the dispenser at a predetermined rate, either by gravity or by mechanical means such as a pump.
As the solution is dispensed through the electrically-conducting dispenser, the high electric potential between the dispenser and the collector leads to the formation of uniform fibers which are deposited on the collector.
As the fibers are deposited on the collector they overlap to form a mat, as further described below. Polymer solutions for use in the fiber mat fabrication disclosed herein include, but are not limited to, aqueous solutions having between 5 and 15 percent polymer by weight.
If the fibers are to be utilized in a contact lens as described below, the fibers are preferably formed from a polymer that is the same as the polymer to be used in the remainder of the contact lens, or a polymer that has a similar index of refraction, to reduce negative optical characteristics of the improved contact lens.
Additional polymer precursor solutions are described below. As the fibers are deposited on the collector they form a mat of overlaying fibers.
In some methods of depositing the fibers, the collector is translated in one or more linear dimensions, or in a rotational or orbital manner, perpendicular to the direction of fiber deposition to increase the area over which the fibers are deposited and to improve the consistency of the fiber mat.
After a desired period of deposition, a fiber mat of a certain thickness will be formed, and can be removed from the electrospinning apparatus and prepared for further processing.The following represents MIC susceptibility data for a few medically significant microorganisms. Respiratory tract and urinary tract infections caused by Klebsiella species Some Gram-positive.
As described below, coating the fiber mat alters the characteristics of the fiber mat, including the release of drugs incorporated in the fiber mat.