ANTI-NEOPLASTIC FORMULATIONS

Abstract: Carboplatin is conventionally made into extemporaneous injectable solutions by reconstituting a lyophilisate with water or a dextrose or saline solution. This is difficult and dangerous, and the solutions formed are unstable. The invention provides a stable, ready-made, injectable aqueous carboplatin solution made without reconstituting a lyophilisate - thus, from unlyophilised carboplatin. The solution preferably contains from 10 mg/ml to 15 mg/ml carboplatin, advantageously includes a polyol (up to 10% of mannitol), and a preservative, but is salt-free, and has a pH preferably between 5 and 7.

Description: This invention relates to anti-neoplastic formulations, and concerns in particular long-term stable aqueous solutions of carboplatin suitable for use by injection. Carboplatin - the approved name for the platinum compound cis-Diamine[1,1-cyclobutanedicarboxylato-(2-)-O,O′]platinum [SP-4-27] - is a well known compound for the treatment (especially by injection of an aqueous solution thereof) of various neoplasms, including advanced ovarian carcinoma, either alone or in combination with other chemotherapeutic agents. At present the compound is provided in the form of a lyophilised powder which has to be reconstituted into an injectable form before use, and this reconstitution may be effected by adding sterile water, or 5% aqueous dextrose, or 0.9% aqueous NaCl, to give the desired injectable solution. These reconstituted solutions are prepared extemporaneously - that is, just before they are needed - and it is explicitly stated in the prescribing information of one of the main Manufacturers of the lyophilised powder (Bristol-Myers) that the solutions obtained are stable for only 8 hours at room temperature and for only 24 hours under refrigeration (it is recommended that the solution be discarded after these time periods). Unfortunately, the very act of reconstitution can cause problems if improperly performed, and is best avoided. For this reason a (hitherto unobtainable) ready-made stable solution is considered a superior galenic form. Moreover, another important feature is the safety factor - specifically, the protection of personnel during handling of carboplatin. Anti-neoplastic agents often have rather undesirable effects on normal tissue, and it is known from general pharmaceutical practice that handling of ready-made solutions of such agents involves less of a risk of exposure, and so is safer, than does reconstitution of a lyophilised form just prior to use. Consequently, the need for a ready-made, stable, injectable solution of carboplatin, which would overcome the above drawbacks, merits high consideration. Rather surprisingly it has now been found that these objectives can be attained - and an aqueous solution of carboplatin, stable for at least 18 months at room temperature, can be achieved - by the simple expedient of dissolving unlyophilised carboplatin - that is to say, carboplatin in a form that is not a lyophilisate - in pure, sterile water to form a solution containing at least 10 mg/ml carboplatin. In one aspect, therefore, the invention provides a stable, aqueous, ready-made injectable solution of carboplatin, characterised in that it is made from unlyophilised carboplatin in pure, sterile water and contains at least 10 mg/ml, preferably 10 to 15 mg/ml carboplatin. The aqueous solution of the invention may be simply a solution of (powdered) carboplatin in pure, sterile water. However, the solution may include, if desired, additional ingredients, such as a polyol (e.g., mannitol at around 15 mg/ml), or a preservative (e.g., benzyl alcohol). Most desirably, however, the solution will be salt-free, and should specifically be free of sodium chloride and other ionizable salts, for these appear to have a deleterious effect on the long term stability of the solution. The pH of the carboplatin solution of the invention is preferably above 4, and most preferably from 5 to 7, and usually nothing special has to be done to attain these values. However, if desired the pH can be adjusted, and adjusted above these values. The carboplatin solutions of the invention can be prepared in any convenient way, but as intimated above a practical method is simply to dissolve the carboplatin in sterile water (for injection) at the desired concentration (e.g., 10 to 15 mg/ml). Naturally, the invention extends to carboplatin solution when thus prepared. The carboplatin solutions according to the invention may be presented in any appropriate formthus, for example, suitably packed in a sealed container such as a vial or ampoule. The ready-made carboplatin solutions of the invention can be used safely by nursing staff in the treatment of malignancies. It will be of interest to compare the simplicity allowed by the invention with the procedures recommended by Bristol-Myers, who sell lyophilised carboplatin under the trade name PARAPLATIN. According to the most recent UK ABPI Data Sheet Compendium 1988-89 (page 281), the reconstitution procedure of the lyophilised product is as follows: "Reconstitution: Immediately before use, the content of each vial must be reconstituted with Sterile Water for Injection PhEur, 5% dextrose for injection or 0.9% sodium chloride for injection to a final concentration of 10 mg of PARAPLATIN per ml, using a diluent volume of 15 ml. "Solutions in 5% Dextrose for Injection BP, or Sodium Chloride for injection BP, may be further diluted with the same vehicles originally used for reconstitution, to concentrations as low as 0.5 mg/ml (500 microgram/ml), while solutions originally reconstituted with Sterile water for Injection PhEur may be further diluted with either of these two fluids." Moreover, having regard to the recommended use of sodium chloride solutions, the contrary conclusions of Cheung Y W et al , of the Analytical and Product Development Section, National Cancer Institute, Bethesda, will also be of interest. They published an article in the Am. J. Hosp. Pharm. 1987, Jan;44(1): p.124-30, on the stability of cisplatin, iproplatin, carboplatin, and tetraplatin in commonly used intravenous solutions, and they came to the conclusion: "Carboplatin and iproplatin are stable for 24 hours in all the infusion fluids studied, but carboplatin should not be diluted with solutions containing chloride ions because of possible conversion to cisplatin." The present invention will now be described, though by way of illustration only, with reference to the following Examples. Example 1 Preparation of 15 mg/ml aqueous carboplatin solutions with and without mannitol 5 g of carboplatin were dissolved in sterile water up to a value of 333 ml (15 mg/ml). From the solution obtained 150 ml were separated (solution B) and 2.25 g of mannitol were added thereto. The other part was kept unchanged (solution A). The solutions obtained were filled into amber moulded 20 ml vials and sealed with Teflon-lined caps, West 541. The solutions obtained are shown in Table I below. The above two solutions were stored at room temperature for 15 months, then tested for stability. The results are shown in Table II below. Example 2 Preparation of a 10 mg/ml aqueous carboplatin solution with mannitol A 10 mg/ml carboplatin solution was prepared from the following ingredients: Method of preparation The carboplatin was dissolved in some of the water for injections, followed by the mannitol, the formed solution (C) was then made up to volume with water for injections. The pH was not adjusted. Filling The solution was filled into 20 ml amber moulded vials and sealed with grey chlorobutyl rubber caps. Stability results on solution C (with mannitol) are shown in Table III below. Example 3 Preparation of a 10 mg/ml aqueous carboplatin solution with either mannitol or sodium chloride, and at different pH values Various solutions were made up from the ingredients (in mg/ml) shown in Table IV below. Method of preparation 1.9 g of carboplatin was dissolved in 180 ml of water for injections. The solution was divided into two equal portions. 0.95 g of mannitol was dissolved in one portion, and 0.855 g of sodium chloride was dissolved in the other portion. Each portion was then made up to a volume of 95 ml with water for injections. Each of the two solutions was then divided into three equal parts. One of these was made acidic with N HCl, another was made alkaline with N NaOH, and the remaining portion was left unadjusted. Filling Each solution was filled into 6 ml clear drawn vials and sealed with Teflon lined caps. The stability test results are shown in Table V below.

Claims: Claims for the following Contracting States : AT, BE, CH, DE, FR, GB, IT, LU, NL and SE l. A stable, aqueous, ready-made injectable solution of carboplatin, characterised in that it is made from unlyophilised carboplatin in pure, sterile water and contains at least l0 mg/ml carboplatin. 2. A solution according to Claim l, containing l0 to l5 mg/ml unlyophilised carboplatin. 3. A solution according to Claim l or Claim 2, which includes a polyol and/or a preservative. 4. A solution according to claim 3, wherein the polyol is mannitol, and the preservative is benzyl alcohol. 5. A solution according to any of the preceding Claims, wherein the pH is between 5 and 7. 6. A solution according to any of the preceding Claims, packed in a sealed container. 7. A method of making an aqueous carboplatin solution according to any of the preceding Claims, in which unlyophilised carboplatin is dissolved in pure sterile water free of sodium chloride and any other ionizable salts. Claims for the following Contracting States : ES, GR l. A method of making a stable, aqueous, carboplatin solution ready-made for injection, in which unlyophilised carboplatin is dissolved to a concentration of at least l0 mg/ml in pure sterile water free of sodium chloride and any other ionizable salts. 2. A method according to Claim l, in which the unlyophilised carboplatin is dissolved to a concentration of from l0 to l5 mg/ml. 3. A method according to Claim l or Claim 2, in which the solution also includes a polyol and/or a preservative. 4. A method according to Claim 3, wherein the polyol is mannitol, and the preservative is benzyl alcohol. 5. A method according to any of the preceding Claims, wherein the pH lies or is adjusted to between 5 and 7. 6. A method according to any of the preceding Claims, wherein the solution thus made is then packed in a sealed container.

Inventors: GEFFEN, YISRAEL, LEVIUS, HAROLD PHILLIP, SKLARZ, BENJAMIN
Applicants: ABIC LIMITED
Application year: 1989
Main classification: A61K31
IPC codes: A61K31, A61K9, A61K47