Title of Invention

AN INJECTABLE ANTISPASMODIC AND A METHOD OF MAKING THE SAME

Abstract

A stable injectable antispasmodic formulation comprising camylofm dihydrochloride dissolved in water for injection q.s. ; at least one adjuvant glycolic co-solvent, 10 % to 55 % of the total volume of the injectable formulation; at least one pH-adjusting agent in dilute solution to adjust the pH of the formulation to between 4.0 and 7.0t at least one antioxidant, 0% to 5% of the total volume of the formulation; at least one chelating agent, 0% to 4% of the total volume of the formulation; at least one preservative, 0% to 5% of the total volume of the formulation; and at least one surfactant, 0% to 10 % of the total volume of the formulation.

Full Text

FORM - 2 THE PATENTS ACT, 1970 (39 of 1970) & THE PATENTS RULES, 2003 COMPLETE Specification (See section 10 and rule 13) AN ANTISPASMODIC FORMULATION IN STABLE INJECTABLE FORM AND TO A METHOD OF MAKING THE SAME SANJEEV KHANDELWAL, an Indian National of Prem Nivas, 13, Altamount Road, Mumbai 400 026, Maharashtra, India; 11-9-2006 1 THE FOLLOWING SPECIFICATION PARTICULARLY DESCRIBES THE INVENTION AND THE MANNER IN WHICH IT IS TO BE PERFORMED:- 3 1 JAN 2005 FIELD OF INVENTION This invention relates to an antispasmodic formulation in stable injectable form and to a method of making the same particularly for the treatment of colicky pain. r Colicky abdominal pain may be caused by spasm of smooth muscles of various internal abdominal organs such as intestinal colic, biliary colic, renal colic and dysmenorrhoea. WHAT THE INVENTION ENVISAGES This invention envisages an injectable stable composition containing Camylofin dihydrochloride . The injectable composition containing camylofin dihydrochloride in accordance with this invention is stable and effective in relief of spasm. Therapeutic effective amount of Camylofin used in the formulation preferably as camylofin dihydrochloride or any pharmaceutically acceptable salt form or any other steriochemical pure form of it. The formulation whose pH is maintained between 4.0 and 7.0 throughout its shelf life, . preferably contains propylethylene glycols - 300, propylethylene glycols - 400, as a solvent and propylene glycols, at least one antioxidant, at least one chelating agent, at least one preservative, and one surfactant and water for injection . The formulation is typically meant to be administrated into the human body either by slow intravenous infusion, or by intramuscular route. 2 CAMYLOFIN Camylofin dihydrochloride chemically it is isopentyl 2-[2-diethylaminoethylamino]-2-phenyl acetate dihydrochloride of molecular weight 393.4, Molecular Formula C19H32N202 2HC1. Camylofin is a pale yellow oil. Camylofin Dihydrochloride is a white crystalline powder melting point 170 °C and 180 °C, soluble in water. In prior art, chemical structure and pharmaceutical properties of camylofin dihydrochloride have been studied in in detail. Camylofin has a direct papaverine like spasmolytic action on the smooth muscle and a mild atropine like anticholinergic action, making it one of the most potent antispasmodics. It inhibits the enzyme phosphodiesterase, which in turn causes increase in concentration of cyclic AMP and smooth muscle relaxation. Due to its phosphodiesterase enzyme-IV isoenzyme selectivity, this drug does not interfere with uterine contractility. LD 50 in mice 760 mg/kg orally; 1.35 gm/ kg s.c; 49.2 mg/kg i.v. Camylofin dihydrochloride primarily acts on smooth muscles (intestine, ureter, cervix) whereas its influence on glands, eyes, heart and circulation is slight and of no clinical significance. It has very mild anticholinergic side effects like dryness of mouth, dilatation of pupils, paralysis of accommodation and palpitations ._It has a wide margin of safety. The ratio of the effective therapeutic dose to the toxicity dose in animal studies varied from 1:40 to 1:150.5 In the prior art it was not possible to obtain a stable camylofin in injectable form having a useful extended shelf life. Camylofin hydrolyzes in water and loses its potency quickly in solution. This has acted as a deterrent in making camylofin in an injectable form. The loss of potency is nearly ten percent within a month of manufacture. 3 An aspect of the invention comprises the incorporation of ingredients or excipients for making a stable pH adjusted formulation of this invention and comprises at least one adjuvant solvent, at least one antioxidant(s), at least one chelating agent, at least one preservative(s), and at least one surfactant. According to this invention there is provided a stable injectable antispasmodic formulation comprising camylofin dihydrochloride dissolved in water for injection q.s. , at least one adjuvant glycolic co-solvent, 10 % to 55 % of the total volume of the injectable formulation; at least one pH-adjusting agent in dilute solution to adjust the pH of the formulation to between 4.0 and 7.0, at least one antioxidant, 0% to 5% of the total volume of the formulation; at least one chelating agent, 0% to 4% of the total volume of the formulation; at least one preservative, 0% to 5% of the total volume of the formulation; and at least one surfactant, 0% to 10 % of the total volume of the formulation. "The formulation includes glycolic co-solvents along with the water for injection which may be one or in combination that is selected from the glycols such as propylene glycol, polyethylene glycols - 300, polyethylene glycols - 400. Unexpectedly and surprisingly, the co solvent prevents the hydrolysis of camylofm and therefore the camylofin remains stable and potent throughout the period of the shelf life of the product." The injectable formulation contains antioxidants that mainly prevent the oxidation of the active drug and to stabilize the formulation throughout the shelf life of the formulation. The anti-oxidant used in the formulation 4 is selected from the group consisting of sodium metabisulfide, sodium sulfide, sodium disulfide. The formulation contains chelating agent that forms a complex with the oxidizing agent and thus prevent oxidation of the active drug and thus potentiate the stabilizing action of the other antioxidants used thus stabilize the formulation throughout the shelf life of the formulation. The chelating agent used in the formulation is preferably sodium salt of EDTA (ethylene diamino tetra acetic acid). The formulation contains surfactant that mainly solubilizes the drug in the medium and thus prevent the precipitation of drug that may occur during the storage of the formulation. The surfactant used in the formulation is selected from the group of polysorbates. The formulation preferably contain polysorbate 80. Another aspect of the invention comprises the incorporation of ingredients or excipients for adjusting the pH. The pH of the injection is the singlemost crucial parameter for stability of the drug in the formulation. The formulation of this invention comprises at least one pH-adjusting agent in its dilute solution that may be preferably sodium hydroxide, hydrochloric acid, citric acid, ammonium acetate, glacial acetic acid, ammonium acetate, sodium acetate. The pH of the formulation is kept within the range of 4.0 to 7.0 throughout its shelf life. The formulation contains preservatives that mainly prevent the deterioration of the formulation from the microbial contamination. The preservative used in the formulation is a pharmaceutically acceptable 5 material and is preferably selected from the group of benzyl alcohol, methyl paraben, propyl paraben and the like . The preservative may be used optionally in the formulation where the quantity of the said adjuvant solvents is more than 40 % of the total volume. The adjuvant solvent itself acting as a preservative. A preferred content of added preservative is from 0.001% to 5% of the total volume of the formulation. According to another aspect of this invention there is provided a process of making a stable injectable antispasmodic formulation comprising camylofin dihydrochloride which comprises the steps, carried out throughout in an inert atmosphere, of [a] dissolving dispensed quantity of camylofin dihydrochloride in fresh water for injection to obtain a clear solution; [b] transferring the clear solution to a stainless steel reaction vessel containing a dispensed quantity of an adjuvant co solvent; [c] stirring the clear solution and the co solvent for 10 to 30 minutes to obtain a homogenous solution; [d] mixing together dispensed quantities of an antioxidant and a chelating agent in water for injection to form an antioxidant-chelating agent solution and adding the an antioxidant -chelating agent solution to the homogenous solution and stirring for 10 to 30 minutes to obtain an active ingredient- antioxidant-chelating agent solution; [e] adding dispensed quantities of a preservative and a surfactant dissolved in water for injection to the active ingredient- antioxidant- chelating agent solution to obtain a non pH adjusted injectable formulation; [f] checking the pH of the non pH adjusted injectable formulation; [g] adjusting the pH of the non pH adjusted injectable formulation to lie between pH 4.0 and 7.0; 6 [h] adding water for injection to the pH adjusted injectable formulation to make up volume to obtain unfiltered injectable formulation; [i] filtering the unfiltered injectable formulation through a sterile membrane filter assembly using nitrogen pressure and collecting the filtered injectable solution being the stable injectable antispasmodic formuation for filing in sterile nitrogen flushed ampules. The invention will now be described with reference to the accompanying examples which are by no means limiting EXAMPLES: Example - 1 Manufacturing process: 1. Washing and sterilization: After completion of the process of washing and sterilization of ampoules, these were transferred to a filling area though a double door chamber. 2. Preparation of the solution: The mixing of injection solution under nitrogen was carried out throughout the manufacturing operation. 18.50 kgs of Propylene Glycol and 34.50 kgs of Polyethylene Glycol 300 were transferred to a 100 lits capacity s.s. Vessel and mixed for 10 minutes. Meanwhile, 2.500 kgs of camylofin dihydrochloride was dissolved in 10.00 lits of fresh water for injection. The clear solution was added to the s.s. Vessel and stirred for 10 minutes. 0.250 kgs of sodium metabisulphite was dissolved in 5.00 lits. of fresh water for injection and the solution was added to the s.s. Vessel and stirred for 10 minutes. 2.00 kgs of Benzyl Alcohol was added to the s.s. Vessel slowly and gradually under continuous stirring. 7 After the addition was completed the resultant solution was stirred for 10 minutes, polysorbate 80 2.00 kg was added slowly under constant stirring for about 10 minutes, approx. 30.00 lits. Of fresh water for injection was added to make up the volume to about 90.00 lits and mixed by stirring for 30 minutes. The pH value of solution was checked and found to be between 2.0 and 3. 0..60 kg of sodium hydroxide was dissolved in sufficient fresh water for injection to produce 3.0 lits. Cooled(20% w/v solution). And Added to s.s. Vessel in suitable portions, under continuous stirring to adjust the pH Value of injection solution between 4.0 and 7.0. Sufficient fresh water for injection was added to make up the final volume of the batch to 100.0 lits and Mixed by stirring for 30 minutes. Actual pH recorded was 5.8 filtration Filtration The Camylofm Dihydrochloride Injection solution was filtered through sterile membrane filter assembly (0.22 micron)using nitrogen pressure and collected in four sterilized 50 lits. s.s. pressure vessels with aspirators (vent). Filling of Ampules The hopper of the fiiling machine was loaded with sterile ampules. Terminal Sterilization Terminal sterilization of filled ampoules was done by moist heat steam sterilization process at 121°C or 15 lb/sq.inch for 20 minutes. Example - 2 Manufacturing process: 1. Washing and sterilization: 8 After completion of the regular process of washing and sterilization of the ampoules, then these are transfer to the filling area though the double door chamber. 2. Preparation of the solution: The mixing of injection solution under nitrogen was carried out throughout the manufacturing operation. 40.00 kgs of Propylene Glycol was transferred to a 100 lits capacity s.s. Vessel and mixed for 10 minutes. 2.500 kgs of camylofm dihydrochloride in 10.00 lits of fresh water for injection was added in clear solution to s.s. Vessel and stirred for 10 minutes. 0.250 kgs of sodium metabisulphite and 0.100 kg of disodium editate were added in 5.00 lits. of fresh water for injection. This solution was added to the s.s. Vessel and stirred for 10 minutes. 2.00 kgs of Benzyl Alcohol was added to the s.s. Vessel slowly and gradually under continuous stirring. After the addition was completed it was stirred for 10 minutes. To s.s. vessel approx. 30.00 lits. of fresh water for injection was added to make up the volume to about 80.00 lits and mixed by stirring for 30 minutes, polysorbate 80 2.00 kg was added slowly under constant stirring for about 10 minutes. The pH value of solution was checked (should be between 2.0 and 4.0). 0..60 kg of sodium hydroxide was dissolved in sufficient fresh water for injection to produce 3.0 lits. Cooled(20% w/v solution). And added to s.s. Vessel in suitable portions, under continuous stirring to adjust the pH Value of injection solution between 4.0 and 7.0. Sufficient fresh water for injection was added to make up the final volume of the batch to 100.0 lits and Mixed by stirring for 30 minutes. Actual pH recorded 4.6 3. Filtration 9 The Camylofm Dihydrochloride Injection solution was filtered through sterile membrane filter assembly (0.22 micron)using nitrogen pressure and collected in four sterilized 50 lits. s.s. pressure vessels with aspirators (vent). Similar process was carried out as in the earlier examples for filling and sealing. The terminal solution was avoided. Example - 3 Manufacturing process: 1. Washing and sterilization: After completion of the regular process of washing and sterilization of the ampoules, then these are transfered to the filling area though the double door chamber. 2. Preparation of the solution: The mixing of injection solution under nitrogen was carried out throughout the manufacturing operation. 45.00 kgs of Polyethylene Glycol 300 were transferred to a 100 lits capacity s.s. vessel and mixed for 10 minutes. 2.500 kgs of camylofin dihydrochloride was dissolved in 10.00 lits of fresh water for injection. And added to s.s. vessel and stirred for 10 minutes. 0.200 kgs of sodium metabisulphite and 0.100 kg of disodium editate were dissolved in 5.00 lits. of fresh water for injection and added to s.s. vessel and stirred for 10 minutes. 1.00 kg of Benzyl Alcohol was added to s.s. Vessel slowly and gradually under continuous stirring. After the addition was completed the slution was stirred for 10 minutes and polysorbate 80 2.00 kg was added slowly under constant stirring for about 10 minutes. To s.s. vessel approx. 30.00 lits. of fresh water for injection was added to make up the volume to about 10 80.00 lits and mixed by stirring for 30 minutes. The pH value of solution was checked (should be between 2.0 and 4.0). 0..60 kg of sodium hydroxide was dissolved in sufficient fresh water for injection to produce 3.0 lits. Cooled(20% w/v solution). And Added to s.s. Vessel in suitable portions, under continuous stirring to adjust the pH Value of injection solution between 4.0 and 7.0. Sufficient fresh water for injection was added to make up the final volume of the batch to 100.0 lits and Mixed by stirring for 30 minutes. Actual pH recorded 4.9 3. Filtration The Camylofm Dihydrochloride Injection solution was filtered through sterile membrane filter assembly (0.22 micron)using nitrogen pressure and collected in four sterilized 50 lits. s.s. pressure vessels with aspirators (vent). Similar process was carried out as in the earlier examples for filling and sealing. The terminal solution was avoided. Example -4 Manufacturing process: 1. Washing and sterilization: After completion of the regular process of washing and sterilization of the ampoules, these were transferred to the filling area though a double door chamber. 2. Preparation of the solution: The mixing of injection solution under nitrogen was carried out throughout the manufacturing operation. 45.00 kgs of Propylene Glycol was transferred to a 100 lits capacity s.s. vessel and mixed for 10 11 minutes. 2.500 kgs of camylofin dihydrochloride was dissolved in 10.00 lits of fresh water for injection. The clear solution was added to s.s. vessel and stirred for 10 minutes. 0.250 kgs of sodium metabisulphite and 0.100 kg of disodium editate were dissolved in 5.00 lits. of fresh water for injection and added to s.s. vessel and stirred for 10 minutes. After the addition was completed the solution was stirred for 10 minutes. To the s.s. vessel approx. 30.00 lits. of fresh water for injection was added to make up the volume to about 80.00 lits and mixed by stirring for 30 minutes. The pH value of solution was checked (was between 2.0 and 4.0). 0..60 kg of sodium hydroxide was dissolved in sufficient fresh water for injection to produce 3.0 lits. Cooled(20% w/v solution). And Added to s.s. Vessel in suitable portions, under continuous stirring to adjust the pH Value of injection solution between 4.0 and 7.0. Sufficient fresh water for injection was added to make up the final volume of the batch to 100.0 litsand Mixed by stirring for 30 minutes.Actual pH recorded was 5.6. 3. Filtration The Camylofin Dihydrochloride Injection solution was filtered through sterile membrane filter assembly (0.22 micron)using nitrogen pressure and collected in four sterilized 50 lits. s.s. pressure vessels with aspirators (vent). Similar process was carried out as in the earlier examples for filling and sealing. The terminal solution was avoided. "CLINICAL STUDY" Objective - To determine the efficacy, onset of action, duration of action and adverse reactions of intravenous Camylofin Dihydrochloride 12 injectable formulation in accordance with this invention given in patients with colic due to smooth muscle spasm. "METHODOLOGY:" This multicentric trial was conducted by 35 doctors in the following indications: 1) Intestinal colic 2) Renal colic 3) Biliary colic and 4) Primary Dysmenorrhea. Cases requiring surgical intervention were excluded and treated by conventional surgical means. Children below 12 years were excluded from the study although the drug is not contraindicated in children. This exclusion was made on the basis of the legal problems associated with the clinical trial in children. After diagnosis, severity of pain was graded on a scale of 1- 10. 25mg of camylofin diHCl in 1ml (single ampoule) was given intravenously slowly over a period of l min. The patients were kept under constant observation and following points were noted: 1. Degree of relief in-patient who responded either good response or no response 2. Duration of relief 3. Follow up of repeated dose in patients who required second dose because of recurrence of pain. 4. Adverse reaction RESULTS: 13 The study was conducted in a total of 209 patients, 73 patients with intestinal colic, 88 patients with renal colic, 36 patients with billiary colic and 12 patients suffering from dysmenorrhea. The severity of pain in all cases were reported on the arithmetical scale of 1 to 10 with numbers 1 to 3 indicating mild pain, numbers 4 to 6 indicating moderate pain and numbers 7 to 10 indicating severe pain. INTESTINAL COLIC: Among the 73 patients with intestinal colic, 5 patients had reported mild pain, 26 patients had reported moderate pain and 42 patients had reported severe pain. 67 (91 %) patients reported good relief after treatment with Camylofm Dihydrochloride intravenous injection in accordance with this invention . The duration of relief was up to 1 hr in 20 cases, between 1-2 hrs in 20 cases and over 2 hrs in 20 cases. Duration of relief was not reported in 7 cases due to lack of follow up. The dose was required to be repeated in 13 cases. , RENAL COLIC: Out of 88 patients with renal colic, 4 patients reported mild pain, 20 patients reported moderate pain and 64 patients reported with severe pain. A total of 83 (94%) patients reported good relief after treatment with Camylofm Dihydrochloride intravenous injection. The remaining 5 patients (5.6%) reported no relief after treatment with Camylofm Dihydrochloride intravenous injection. The duration of relief was upto 1 hr in 24 cases, 1 to 2 hrs in 24 cases and over 2 hrs in 25 cases. In 10 patients the duration of relief was not reported due to lack of follow up. A repeat dose was required in 29 patients. BILIARY COLIC: 14 Out of 36 cases reported with biliary colic, 11 patients had moderate pain and 25 cases were reported with severe pain. 33(91%) patients reported good relief after treatment with Camylofin Dihydrochloride intravenous, injection. The duration of relief was up to 1 hr in 7 cases, between 1 to 2 hrs in 12 cases and over 2 hrs in 12 cases. The duration of relief was not reported in 2 cases due to lack o follow-up. The dose was required to be repeated in 15 cases. DYSMENORRHOEA: Out of 12 cases reported with dysmenorrhoea, 2 had mild pain, 3 had moderate pain and 7 had severe pain. All 12 (100%) patients reported good relief after treatment with Camylofin Dihydrochloride intravenous injection. The duration of relief was upto 2 hrs in 7 patients and over 2 hrs in 5 patients and the injection was required to be repeated in 2 patients. Therefore, out of the total 209 patients, 195 (95%) patients showed good response to Camylofin Dihydrochloride intravenous injection. The adverse reactions reported were dizziness (10 patients), drowsiness (2 patients), burning at the site of injection (1 patient), Palpitation and fall in blood pressure (2 patients), nausea and vomiting (3 patients) and dryness of mouth (11 patients). The above result shows that the symptomatic relief with Camylofin Dihydrochloride intravenous injection in accordance with this invention from the colicky pain due to smooth muscle pain in the intestines, renal tract, biliary tract and primary dysmenorrhoea is excellent. However, it must be noted that although all patients should have responded, theoretically there were a small number of treatment failures where there was no relief. It is difficult to conclude as to why some patients did not respond. Possibly the diagnosis of the causative factor for colicky pain 15 was not complete or accurate. It is possible that there may have been some surgical causes of the pain in some patients. It is also possible that a higher dose may have been given relief in some of the non-responders. In the above study it is obvious that most of the patients were symptomatically relieved from the colicky pain of the 4 conditions for which the drug was administered. The incidence of adverse reactions was comparatively few and was not severe. Camylofm Dihydrochloride intravenous injection in accordance with this invention is a very effective treatment for symptomatic relief of abdominal pain caused by spasm of smooth muscles of the abdominal viscera. The adverse reactions were very mild and few. The requirements to be met by a good antispasmodic are naturally very comprehensive. The following five points should be especially detailed: - 1. The antispasmodic should act promptly. 2. Its effect should last as long as possible. 3. It must be free from side-effects. 4. Its therapeutic spectrum as regards the organs prone to spasm should be as extensive as possible. 5. It is desirable that the drug should have a wide variety of presentations: as tablets, oral solution and injection ampoules." Summary of toxicological findings: Toxicity and tolerance: The toxicity of Camylofm Dihydrochloride injectable formulation in accordance with this invention was found to be low. The medium lethal dose (LD50) for mice was Intravenously 40.00 mg. per kilo Intramuscularly 360.00 mg. per kilo 16 A comparison of LD50 with ED50 (medium effective dose producing antispasmodic effects) in various species of animals demonstrated a wide margin of safety, i.e. a therapeutic ratio of 1:40 to 1:150. Tolerance and influence on respiration and circulation were tested on dogs and cats. It was shown that even on administration of ten times the therapeutic dose, especially if administered by slow intravenous injection, no accidents occurred. In accelerated studies, Long-continued use of Camylofm Dihydrochloride did not produce any lesions in parenchymatous organs, in the blood pressure or in metabolism. Camylofm Dihydrochloride had no central point of attack, certainly not in the sense of a central analgesic action. But, according to its chemical structure, it exerted a notable local-anaesthetic effect, which on the rabbit's eye showed intensity comparable to that of cocaine. Local tolerance: Any fear that tissue lesion might occur by the direct action of Camylofm Dihydrochloride can therefore be excluded. Repeated intramuscular and subcutaneous injections in numerous histologically controlled experiments did not produce abscesses, inflammation, or necroses. Repeated intravenous injection into rabbit's ear were tolerated without reaction. The injectable formulation in accordance with this invention was found to be stable in accelerated studies did not exhibit in microbial contamination and no precipitation. The drug remained in solution throughout the shelf life without degradation or reduced potency. .17 I Claim: [1] A stable injectable antispasmodic formulation comprising camylofm dihydrochloride dissolved in water for injection q.s. ; at least one adjuvant glycolic co-solvent, 10 % to 55 % of the total volume of the injectable formulation; at least one pH-adjusting agent in dilute solution to adjust the pH of the formulation to between 4.0 and 7.0t at least one antioxidant, 0% to 5% of the total volume of the formulation; at least one chelating agent, 0% to 4% of the total volume of the formulation; at least one preservative, 0% to 5% of the total volume of the formulation; and at least one surfactant, 0% to 10 % of the total volume of the formulation. [2] The stable injectable antispasmodic formulation comprising camylofm dihydrochloride as claimed in claim 1, wherein the glycolic solvent is selected from a group of solvents containing propylene glycol, polyethylene glycol - 300 or polyethylene glycol - 400 . [3] The stable injectable antispasmodic formulation comprising camylofm dihydrochloride as claimed in claim 1, wherein the antioxidant is selected from a group consisting of sodium metabisulfide, sodium sulfide or sodium disulfide. [4] The stable injectable antispasmodic formulation comprising camylofm dihydrochloride as claimed in claim 1, wherein the chelating agent used in the formulation is the sodium salt of EDTA (ethylene diamino tetra acetic acid). 18 [5] The stable injectable antispasmodic formulation comprising camylofin dihydrochloride as claimed in claim 1, wherein the surfactant in the formulation is selected from the group of polysorbates and is preferably polysorbate 80. [6] The stable injectable antispasmodic formulation comprising camylofin dihydrochloride as claimed in claim 1, wherein the pH-adjusting agent in its dilute solution is selected from a group consisting of sodium hydroxide, hydrochloric acid, citric acid, ammonium acetate, glacial acetic acid, ammonium acetate and sodium acetate. [7] The stable injectable antispasmodic formulation comprising camylofin dihydrochloride as claimed in claim 1, wherein the preservative is selected from a group consisting of benzyl alcohol, methyl paraben, and propyl paraben. [8] A process of making a stable injectable antispasmodic formulation comprising camylofin dihydrochloride as claimed in any one of the preceding claims which comprises the steps, carried out throughout in an inert atmosphere, of [a] dissolving dispensed quantity of camylofin dihydrochloride in fresh water for injection to obtain a clear solution; [b] transferring the clear solution to a stainless steel reaction vessel containing a dispensed quantity of an adjuvant co solvent; [c] stirring the clear solution and the co solvent for about 10 to 30 minutes to obtain a homogenous solution; [d] mixing together dispensed quantities of an antioxidant and a chelating agent in water for injection to form an antioxidant-chelating agent solution and adding the an antioxidant -chelating agent solution to the 19 homogenous solution and stirring for 10 to 30 minutes to obtain an active ingredient- antioxidant-chelating agent solution; [e] adding dispensed quantities of a preservative and a surfactant dissolved in water for injection to the active ingredient- antioxidant- chelating agent solution to obtain a non pH adjusted injectable formulation; [f] checking the pH of the non pH adjusted injectable formulation; [g] adjusting the pH of the non pH adjusted injectable formulation to lie between pH 4.0 and 7.0; [h] adding water for injection to the pH adjusted injectable formulation to make up volume to obtain unfiltered injectable formulation; [i] filtering the unfiltered injectable formulation through a sterile membrane filter assembly using nitrogen pressure and collecting the filtered injectable solution being the stable injectable antispasmodic formuation for filing in sterile nitrogen flushed ampoules. Dated this 27tfsday of January 2005. MOHAN DEWAN OF R.K.DEWAN & COMPANY APPLICANT'S PATENT ATTORNEY 20

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