Field of the invention

The present invention relates to a novel stable composition for intravenous administration comprising 2-S-(n-Butylsulfonylamino)-3-[4-(4-(piperidin-4-yl)butyloxy)phenyl]propionic acid monohydrochloride (Tirofiban hydrochloride) as active pharmaceutical ingredient. More specifically, the present invention discloses a composition that exhibits improved stability of the formulation and complies with the particulate matter beyond 24 months of storage at 25°C and 6 months at 40 °C.

Background of the invention

Tirofiban HC1 is a non-peptide antagonist of the platelet-glycoprotien (GP) Ilb/IIIa receptor and inhibits the platelet aggregation. Tirofiban HC1 in combination with Heparin is indicated for the treatment of acute coronary syndrome, including patients who are to be managed medicinally and those undergoing PTCA or Atherectomy. US patent 5,880,136 discloses a series of non-peptide derivatives that are useful in the prevention and treatment of diseases caused by thrombus formation. The compound as per the general structure described in this patent is Tirofiban HC1 salt i.e. N-(butylsulfonyl)-0-[4-(4-piperidinyl)butyl]-L-tyrosine monohydrochloride

U.S.Pat.No. 5,965,581 discloses a composition comprising about 0.25 mg/ml 2-S-(n-Butylsulfonylamino)-3 -[4-(4-(piperdin-4-yl)butyloxylphenyl]propionic acid, about 8 mg/ml sodium chloride, about 2.7 mg/ml sodium citrate dihydrate, about 0.16 mg/ml citric acid anhydrous, wherein the composition osmolality concentration is between about 250 - 310 mOsmol/kg and the pH is in the range of between 5.5-6.5.

The patent also specifies that the formulation should be substantially free of phosphate buffer as the formulation with phosphate buffer is likely to show increased particulate matter after 24 months storage.

Therefore it is object of the present invention is to develop a stable formulation for Tirofiban hydrochloride which provides better stability on the formulation as well as comply with the requirements of injectables when tested for particulate matter and absence of degradation product.

It is surprisingly found that stability of the composition comprising tirofiban increased manifold when mannitol used in a particular proportion with the phosphate buffer.

Summary of the invention

It is therefore a stable composition of the present invention comprising 0.025 - lmg of tirofiban; mannitol as a stabilizing agent at a concentration of 5 to 100 mg/mL, more preferably in the range of 5 to 50 mg/ml; a tonicity adjustor with the osmolality of the formulation adjusted in the range of 240 - 360 mOsm to render it isotonic,wherein tonicity adjustor such as sodium chloride, sorbitol, dextrose and the like; additional pH adjusters and buffers to maintain the pH of the formulation in the range of 5.0 to 7.0, more preferably in the range of 5.5 to 6.5 such as hydrochloric acid and /sodium hydroxide or buffering agents such as phosphate, acetate, tartarate or citrate, more preferably phosphate buffer.

The concentration of buffering agents is in the range of 2 to 100 mM, preferably in the range of 2 to 20 mM.

The composition of the present invention complies with the compendial monograph for visible and sub-visible particulate matter and is essentially free from the degradation products during processing and storage.

Other objects, features, advantages and aspects of the present invention will become apparent to those of skill from the following description. It should be understood, however, that the following description and the specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only. Various changes and modifications within the spirit and scope of the disclosed invention will become readily apparent to those skilled in the art from reading the following description and from reading the other parts of the present disclosure.
Detailed Description

It is therefore a stable composition of the present invention comprising 0.025 - lmg of tirofiban; mannitol at a concentration of 5 to 100 mg/mL, more preferably in the range of 5 to 50 mg; a tonicity adjustor with the osmolality of the formulation adjusted in the range of 240 - 360 mOsm to render it isotonic; pH adjusters to maintain the pH of the formulation in the range of 5.0 to 7.0, more preferably in the range of 5.5 to 6.5.

The pH adjuster is hydrochloric acid or sodium hydroxide or buffering agents such as phosphate, acetate, tartarate or citrate buffer, more preferably phosphate buffer. The required amount of sodium dihydrogen phosphate will be added and dissolved in water for injection. The pH of the buffer will be adjusted if required with Hydrochloric acid/sodium hydroxide and made up to required volume with water for Injection.

The tonicity adjusting agents are such as sodium chloride, sorbitol, dextrose and the like.

The concentration of buffering agents is in the range of 2 to 100 mM, preferably in the rangeof2to20mM.

The composition of the present invention exhibits synergistic activity and an improved stability on the formulation minimizing the formation of an impurity at the relative retention time of 1.5 with respect to the active peak in the HPLC chromatogram when tirofiban and mannitol are in a range as disclosed herein. The peak is a predominant impurity formed during acid and/heat stress and has a Xmax of 275 nm as against the parent molecule that exhibits a maximum at 225 nm. The degradation impurity is seen to increase in the prior art formulation comprising of citrate buffer and sodium chloride as tonicity agent. This impurity is seen to be formed to an even larger extent in other buffer systems such as acetate or phosphate buffers compared to the citrate buffer when formulated with sodium chloride as a tonicity adjusting agent. This may have been the cause for physical instability of these formulations thus contributing to the particulate matter as mentioned in the prior art.
Addition of mannitol stabilizes the formulation and the degradation profile does not show formation of this impurity irrespective of the buffer system used. The formulation containing mannitol thus exhibits better physicochemical stability than the prior art formulation. In addition, for a premixed infusion, the stabilizing properties of mannitol are retained even when added at a lower concentration along with other tonicity adjusting agents such as sodium chloride or dextrose.

The developed pharmaceutical composition comprises an aqueous pharmaceutical composition for IV infusion both as a concentrate that has to be diluted before injection and as a premixed infusion. The composition specifically contains

The composition further comprising a pH adjusting agent phosphate or acetate buffer to maintain the composition of the present invention in the pH 5 to 7.

The aqueous compositions containing tirofiban hydrochloride as active ingredient were prepared using different combinations of buffering and tonicity agents and subjected to autoclaving at 121°C. The samples were evaluated for HPLC profile more specifically with respect to formation of impurity at RRT 1.5. The evaluation also includes the prior art formulation for comparison purposes.

The formulations that were evaluated for formation of the impurity at RRT 1.5 included compositions containing mannitol or sodium chloride or dextrose along with either of the buffering systems such as acetate buffer, citrate buffer or phosphate buffer in the range of 5 to 100 mmol. The composition also included formulation containing only sodium chloride or mannitol or dextrose as tonicity adjusting agents.

The following examples illustrate the above-described invention. However, it is not intended to restrict the scope of this invention in any manner. All publications and patents mentioned herein are incorporate by reference in their entirety as if set forth in full herein.

Method of Preparation:

Compositions disclosed in Examples 1-8 are prepared with the forgoing procedure. To water for Injection weighed amount of buffer was added and dissolved. To the buffer solution active pharmaceutical ingredient, isotonicity agent &/stabilizer are added and dissolved. If required the pH of the formulation is adjusted to 5.5-6.5 with hydrochloric acid/sodium hydroxide and the formulation is made up to required volume with water for Injection. The formulation will be filtered and filled into 50 mL USP Type I glass vials with a fill volume of 50 mL and stoppered with halobutyl rubber stopper and sealed. The vials will be subjected to terminal sterilization as per the validated cycle.

Compositions for the pre-mixed infusion

Composition 9:

Method of Preparation:

Composition disclosed in Examples 9-13 is prepared with the foregoing method. To water for Injection weighed amount of buffer was added and dissolved. To the buffer solution active pharmaceutical ingredient, isotonicity agent /stabilizer are added and dissolved. If required the pH of the formulation is adjusted to 5.5-6.5 with hydrochloric acid/sodium hydroxide and the formulation is made up to required volume with water for Injection. The formulation will be filtered and filled into 250 mL infusion bag with a fill volume of 250 mL and stoppered with twist off port. The bags will be subjected to terminal sterilization as per the validated cycle.

The samples from the above were subjected to autoclaving. All the samples that contained no isotonicity adjusting agent or sodium chloride as a tonicity adjusting agent showed a peak that showed gradual increase with the duration of autoclaving at RRT 1.5 with respect to the active peak. Though the peak is formed in all the buffer systems with sodium chloride as tonicity adjusting agent, the compositions containing phosphate or acetate buffer showed an increased propensity for formation of this impurity compared to the prior art formulation containing citrate buffer. Surprisingly, the compositions containing mannitol did not show detectable levels of this impurity with or without any buffer. Other tonicity

adjusting agents such as sorbitol or dextrose did not show significant stabilizing effect with respect to formation of this impurity.

It was hypothesized that formation of particulate matter noted during the evaluation of phosphate buffered compositions while developing the prior part formulation may be related to formation of this relatively nonpolar degradation impurity at RRT 1.5 when sodium chloride is employed as tonicity adjusting agent. Hence the chosen compositions from the above examples were evaluated for particulate matter under long term storage conditions.

Contrary to the observations documented in the prior art patent, it was observed that after 24 months of storage, phosphate buffered compositions containing mannitol are devoid of visible and sub visible particulate matter. Similar results are observed with other buffers as well when mannitol was employed as a tonicity agent. The pre-mixed infusion manufactured in flexible bags also showed stability with respect to the formation of impurity at RRT 1.5 as well as particulate matter when mannitol was employed as a stabilizer at an equivalent concentration to that of the concentrate while employing sodium chloride or dextrose as tonicity adjusting agents.

Based on the results, formulation containing phosphate buffer as buffering agent and mannitol as stabilizing as well as tonicity agent was prepared and subjected to accelerated and long term studies. The formulations in the art was also prepared simultaneously and subjected to similar storage conditions.

The particulate matter results of samples for the concentrate and the infusion in comparison with composition in the prior art are as follows:

The improvement in stability, particle formation and decomposition products is very much minimized in the composition of the present invention over the prior art composition. This improvement is due to the synergistic effect of the ingredients present in the composition.

We claim:

1. A stable composition comprising;

(a) 0.025 - lmg of tirofiban;

(b) a stabilizing agent;

(c) a tonicity adjusting agent;

(d) pH adjusting agent and

(e) pharmaceutically acceptable excipients.

2. The composition as claimed in claim 1, wherein stabilizing agent is mannitol with a concentration of 5 to 100 mg/mL, more preferably in the range of 5 to 50 mg/ml.

3. The composition as claimed in claim 1, wherein the tonicity adjusting agent such as sodium chloride, sorbitol, dextrose and the like with the osmolality of the formulation adjusted in the range of 240 - 360 mOsm to render it isotonic.

4. The composition as claimed in claim 1, wherein pH adjusting agent are hydrochloric acid or sodium hydroxide or buffering agents such as phosphate, acetate, tartarate or citrate, more preferably phosphate buffer.

5. The composition as claimed in claim 1, wherein pH of the formulation in the range of 5.0 to 7.0, more preferably in the range of 5.5 to 6.5.

6. The composition as claimed in claim 1, wherein the concentration of buffering agents is in the range of 2 to 100 mM, preferably in the range of 2 to 20 mM.

7. A method for the preparation of composition such as herein described and exemplified.