PARENTERAL FORMULATION OF FLUOROQUINOLONE ANTIBACTERIAL AGENT AND METHOD FOR PREPARATION THEREOF
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an aqueous pharmaceutical formulation comprising a fluoroquinolone antibacterial agent such as Moxifloxacin or pharmaceutical acceptable salt thereof and an effective amount of a tonicity agent such as propylene glycol, in order to achieve appropriate osmolality of the solution. The preferred method of administration is intravenous infusion. The present invention also provides a method of preparation of such formulation.
BACKROUND OF THE INVENTION
Parenteral routes of administration can have significant advantages over oral delivery in some situations. Parenteral administration routes result in a higher blood serum concentration in a shorter amount of time, when compared to oral administration of the same drug. The expected drug serum concentration can be more predictable and the dose can be much lower than other routes of administration because of elimination of loss" of the drug due to metabolism, binding to food and other drugs. This method of administration is preferred in emergency situations and when subjects being treated are unconscious, uncooperative, or unwilling to accept oral medication. Intravenous administration, in which the medication is directly administered into the vein of the patient either by injection or infusion, is a very common method of parenteral administration. The whole amount of drug can either be injected directly into the vein, or it can be infused over a longer period of time. Active ingredients that are administered intravenously are almost always in the form of an aqueous solution, therefore the active ingredient needs to be characterized by sufficient water solubility.
Sufficient water solubility means that the quantity of the active ingredient necessary for successful treatment can be dissolved completely in the aqueous medium to be administered to the patient. Poorly or very poorly water soluble active ingredients can only be administered to the patient by other methods of administration as the volume of aqueous medium required to
dissolve them would be no longer suitable for intravenous administration. In addition, miscibility of the administered solution with the patient's blood is another prerequisite for an active ingredient to be administered by intravenous administration, otherwise the patient runs the risk of severe-embolism or severe necrosis.
Moxifloxacin is an antibiotic from the class of quinolones carboxylic acids of the following formula:
It's chemical name is l-cyclopropyl-7-([S,S]-2,8-diazabicyclo[4.3.0]non-8-yl)-6-fluoro-l,4- dihydro-8-methoxy-4-oxo-3-quinolonecarboxylic acid. Moxifloxacin was first disclosed in EP0350733 Bl as an effective antibacterial agent; however,there is no description of an aqueous pharmaceutical formulation suitable for parenteral administration necessary for patients at intensive care units which cannot be treated orally.
EP 1 206 281B1 claims an aqueous formulation comprising Moxifloxacin hydrochloride and an amount of sodium chloride from 0.4% to 0.9% (w/v) as a tonicity agent.
EP 1 225898B1 claims an aqueous formulation comprising Moxifloxacin hydrochloride, xanthan gum as tonicity agent and an amount of a water soluble calcium salt. Although the above mentioned patent represents an attempt to provide aqueous solutions of Moxifloxacinhydrochloride with adequate physical characteristics, there still exists a need for alternative formulations providing as well adequate chemical characteristics such as the stability of the pharmaceutical composition during storage time.
SUMMARY OF THE INVENTION It is, therefore, an object of the present invention to provide an aqueous pharmaceutical formulation comprising a fluoroquinolone antibacterial agent such as Moxifloxacin or pharmaceutical acceptable salt thereof for parenteral use which has an osmolality adjusted to the physiological conditions of the organism. Another object of the present invention is to provide an aqueous pharmaceutical formulation comprising a fluoroquinolone antibacterial agent such as Moxifloxacin or pharmaceutical acceptable salt thereof for parenteral use that effectively address issues related to the solubility of the active substance, stability of the dosage form as well as physiological acceptability by the patient.
A further approach of the present invention is to provide a method for the preparation of an aqueous pharmaceutical formulation comprising a fluoroquinolone antibacterial agent such as Moxifloxacin or pharmaceutical acceptable salt thereof that deals with the major consideration of sterility when manufacturing dosage forms for parenteral administration.
In accordance with the above objects of the present invention, an aqueous pharmaceutical formulation is provided comprising a fluoroquinolone antibacterial agent such as Moxifloxacin or pharmaceutical acceptable salt thereof as an active ingredient and an effective amount of a pharmaceutically acceptable tonicity agent such as propylene glycol, in order to achieve adequate osmolality of the pharmaceutical dosage form.
According to another embodiment of the present invention, a process for the preparation of an aqueous pharmaceutical formulation is provided comprising a fluoroquinolone antibacterial agent such as Moxifloxacin or pharmaceutical acceptable salt thereof, which comprises:
-Dissolve the active substance at 90% of the total volume of water for injection;
-Addition of Propylene Glycol;
-pH adjustment with NaOH or HC1 if necessary;
-Adjustment to final volume with water for injection;
-Filtration of the solution for sterilization;
-Bottle filling and sealing;
-Terminal sterilization of the product. Other objects and advantages of the present invention will become apparent to those skilled in the art in view of the following detailed description.
DETAILED DESCRIPTION OF THE INVENTION Parenteral administration is non-enteral or non-oral and, therefore, includes all products administered other than by the oral route. The parenteral composition of the present invention is injectable or infusible and is administered via the intravenous (IV), subcutaneous or intramuscular route. A parenteral composition should have a pH close to physiological levels. However, most of the products have a pH value that is a compromise between physiological acceptability, solubility of the active substance and stability of the finished dosage form. Thus, great majority of the marketed products have a pH of between 2 and 12. Additionally, a parenteral product should have an osmolality of between 240mOsm/L to 340mOsm/L in order to be isotonic. Hypoosmotic compositions could lead to haemolysis of the cells, while hyperosmotic compositions to plasmolysis. Furthermore, non isotonic solutions are associated with pain and non tolerance from the patient's side. Accordingly the present invention provides an aqueous parenteral formulation comprising from 0.1% (w/v) to 0.2% (w/v) (on dry bases) of Moxifloxacin hydrochlorideand 1.5% (w/v) to 2.0% (w/v) of propylene glycol. "% (w/v)" is the weight in gr per 100ml of volume, unless otherwise stated. Surprisingly, it has been found that in the presence of propylene glycol, an isotonic solution of Moxifloxacin hydrochloride can be produced but on the same time the active substance dissolves sufficiently and the produced dosage form is stable and suitable for use in parenteral administration.
Parenteral pharmaceutical dosage forms due to the route of administration bypass normal defence barriers of the human body. Thus, the preparation should be made with high degree of care and cautiousness. Such products should be sterile, pyrogen free, isotonic, with physiological pH value or a pH that can be adjusted easily by the body upon administration and stable both chemically and physically. There should be absence of any particulate matter after manufacture as well as after storage of the product. Also the specific gravity of the product has an important role especially on products intended for spinal anaesthesia.
Accordingly, the present invention provides an aqueous pharmaceutical formulation comprising a fluoroquinolone antibiotic agent of the class such as Moxifloxacinand salts thereof for parenteral use having a pH value of from 4 to 5. This pH value provides the optimum area where the active pharmaceutical ingredient dissolves but also can be by human body without any irritation or pain associated with the administration.
In another embodiment, the present invention provides a process for preparing the aqueous pharmaceutical formulation of Moxifloxacin or salt thereof by dissolving the total amount of active ingredient in water for injection and propylene glycol is then added and dissolved.
The pharmaceutical composition of the present invention is preferably used for parenteral administration and more preferably as a solution for intravenous infusion.
The aqueous pharmaceutical composition according to the present invention may also comprise other common excipients used for parenteral administration such as pH adjusting agents or buffers, antioxidants and preservatives. pH adjusting agents which can be used as excipients in the present invention may be: acids such as acetic, boric, citric, lactic, phosphoric, and hydrochloric acids; bases such as sodium hydroxide, sodium phosphate , sodium borate, sodium citrate, sodium acetate, sodium lactate, trishydroxymethylaminomethane and the like.
Preferred buffer agents that can be used in the present invention may be: sodium acetate or potassium acetate, a phosphoric acid/monopotassium phosphate/citric acid combination,
monosodium phosphate or monopotassium phosphate or an aqueous solution of glycerine/strong acid such as hydrochloric acid, citric acid/sodium citrate or potassium hydrogen phthalate.
Such acids, bases and/or buffers are included in an amount necessary to maintain the pH of the aqueous pharmaceutical formulation in a physiologically acceptable range, particularly where the composition is intended for intravenous delivery. The formulation according to the present invention comprises water or a water-based medium as the liquid medium. The liquid medium mainly comprises of water but it may also comprise conventional physiologically acceptable auxiliary substances known to a person skilled in the art.
Various containers are known to be suitable for aqueous pharmaceutical formulations intended for parenteral administration to the patient. The most common containers are glass and plastic bottles and plastic bags. Containers suitable in accordance with the present invention refer to containers which do not interact chemically with the solution for injection in any way to alter the strength, quality, or purity beyond the official requirements under the ordinary conditions of handling, shipment, storage, sale and use.
The following examples illustrate preferred embodiments in accordance with the present invention without limiting the scope or spirit of the invention.
EXAMPLES
Example 1
Table 1 : Composition 1 to 4 of example 1
Four aqueous pharmaceutical compositions were prepared using different tonicity agents. The process used for manufacturing was the same for all of them and comprised the steps of:
-Weight active substance and excipients;
-Sifting the raw materials to eliminate any clumps.
-In 90% of total amount of water for injection (WFI) dissolve the active substance and the tonicity agent;
-Adjust the pH with NaOH or HC1, if necessary;
-Adjust to final volume.
Physical properties such as osmolality and specific gravity of the four compositions were measured and presented in table 2 below. Table 2: Osmolality & specific gravity of composition 1 to 4
In order to achieve the appropriate osmolality for the four composition high amounts of the tonicity agents mannitol, dextrose and citric acid/sodium citrate were used. This resulted in high specific gravity, above 1.01 which is considered as the limit for aqueous non viscous parenteral compositions.
Optimum results were accomplished by the use of propylene glycol as tonicity agent. Composition 1 was stored in stability chambers in long term conditions (25°C/60%RH) and in accelerated conditions (40oC/75%RH) in the final package (glass vial and butyl rubber stopper).
In order to evaluate if the rubber stopper may cause degradation by-products, the vials were stored both upright and reversed in the chambers. The related substances results after six months are presented in the following table.
Table 3: Related substances stability results of composition 1
The above results demonstrate the suitability of composition 1 for parenteral administration. Additionally, there were no particles or sedimentation observed in that period and the microbiological test confirmed the sterility of the product.