US 2013 0336945A1 (19) United States (12) Patent Application Publication (10) Pub. No.: US 2013/0336945 A1 Rustomjee et al. (43) Pub. Date: Dec. 19, 2013 (54) STABLE COMPOSITIONS OF (30) Foreign Application Priority Data TETRAHYDROBOPTERN Mar. 1, 2011 (IN) ........................... 573/MUM/2011 (71) Applicants: Maharukh Tehmasp Rustomjee, Mumbai (IN); Anilkumar Surendrakumar Gandhi, Mumbai (IN) Publication Classification (72) Inventors: Maharukh Tehmasp Rustomjee, (51) Int. Cl. Mumbai (IN); Anilkumar A 6LX3/59 (2006.01) Surendrakumar Gandhi, Mumbai (IN) (52) U.S. Cl. (73) Assignee: RUBICON RESEARCH PRIVATE CPC .................................... A6 IK3I/519 (2013.01) LIMITED, MUNBAI (IN) USPC .......................................... 424/94.1: 514/249 (21) Appl. No.: 14/002,313 (57) ABSTRACT (22) PCT Filed: Mar. 1, 2013 The present invention relates to stable pharmaceutical com (86). PCT No.: PCT/IB12/SO959 positions of tetrahydrobiopterin and processes for producing Such compositions. Particularly the present invention relates S371 (c)(1), to stable pharmaceutical compositions comprising tetrahy (2), (4) Date: Aug. 29, 2013 drobiopterin and at least one stabilizing agent. US 2013/0336945 A1 Dec. 19, 2013 STABLE COMPOSITIONS OF unpalatable. Further the strict regimen of dietary protein is TETRAHYDROBOPTERN practically impossible for patients of all ages to adhere to in daily life. FIELD OF THE INVENTION 0006 Thus there remains a need to obviate the dietary restrictions and replace or Supplement the same with oral 0001. The present invention relates to stable compositions treatment by providing an oral composition of tetrahydro of tetrahydrobiopterin and processes for producing Such com biopterin. positions. Particularly the present invention relates to stable 0007 Further BH4-responsive PAH deficiency has also compositions comprising sapropterin or pharmaceutically been diagnosed as a variant of hyperphenylalaninemia or acceptable salts thereof and at least one stabilizing agent. phenylketonuria caused by mutations in the human PAH gene that responds to oral BH4 loading by stimulating enzyme BACKGROUND OF THE INVENTION activity and therefore lowering serum phenylalanine. BH4 is said to have a chaperon-like effect on PAH synthesis and/or is 0002 Amino acids represent the source of life and make a protecting cofactor against enzyme auto-inactivation and up twenty percent of the human body. They are divided into degradation. two categories—essential amino acids, which are not synthe sized in the body and must be taken from food; and non 0008. Therefore, since administration of BH4, alone has essential amino acids. Phenylalanine is one of the eight essen been proven effective in the treatment of BH4-responsive tial amino acids that is an important precursor for the hyperphenylalaninemia, for which the only available treat synthesis of tyrosine that serves as a precursor for synthesis of ment has been a diet therapy, development of effective treat many neurotransmitters and thyroid hormones. Physiologic ments for the disease, in particular, development of effective requirements for phenylalanine are met exclusively by tetrahydrobiopterin preparations is an urgent need. dietary protein intake. Usual dietary intake of protein pro 0009 Sapropterin dihydrochloride is a synthetic version vides excess amounts of phenylalanine and blood phenylala of naturally occurring tetrahydrobiopterin. Sapropterin dihy nine levels are maintained within non-toxic levels via utiliza drochloride is chemically represented as (6R)-2-amino-6- tion, metabolism and excretion. However when the body is (1R,2S)-1,2-dihydroxypropyl-5,6,7,8-tetrahydro-4(1H)- unable to metabolize phenylalanine to tyrosine, the level of pteridinone dihydrochloride. The 6R-form is phenylalanine in the body is elevated leading to a rare condi pharmacologically effective while the 6S form may cause tion called hyperphenylalaninemia that severely impairs inactivation of phenylalanine hydroxylase, thus inhibiting the effects of the 6R form. Sapropterin dihydrochloride is a crys functions of the central nervous system. talline powder, hygroscopic and very soluble in water with 0003 Hyperphenylalaninemia (HPA) is a congenital solubility being greater than 1 g/ml. It exhibits polymorphism metabolic disorder inherited as an autosomal recessive trait and many crystalline forms have been identified; among all and characterized by the presence of blood phenylalanine the polymorphic forms. Form B was identified to be thermo levels that exceed the limits of the upper reference range of 2 dynamically stable crystalline anhydrate form. Sapropterin mg/dL or 120 mmol/L. HPA is divided into (i) HPA caused dihydrochloride is currently available as oral soluble tablets due to deficiency in enzyme phenylalanine hydroxylase of 100 mg under the brand name KuvanTM. It is marketed by (PAH) that is required for the conversion of ingested pheny BioMarin in the US and Merck Serono in Europe. KuvanTM lalanine to tyrosine, due to absent or mutated PAH enzyme: has been designated as an orphan medication since hyperphe the condition being known as Phenylketonuria (PKU) or (ii) nylalaninemia is a rare disease. KuvanTM is indicated to HPA resulting from a deficiency intetrahydrobiopterin (BH4) reduce blood phenylalanine levels in patients with hyperphe cofactor of the enzyme PAH, due to defects in its biosynthesis nylalaninemia due to tetrahydrobiopterin responsive phe or recycling. nylketonuria. It is to be used in conjunction with phenylala 0004 Tetrahydrobiopterin is a biogenic amine of the natu nine restricted diet. In patients with phenylketonuria the role rally occurring pterin family that is a cofactor for a number of of sapropterin dihydrochloride is to enable endogenous phe different enzymes, including phenylalanine hydroxylase, nylalanine hydroxylase activity and to partially restore oxi tyrosine hydroxylase, tryptophan hydroxylase and nitric dative metabolism of phenylalanine, resulting in decreased oxide synthase regulating their activity and catalysis. These blood phenylalanine levels. In patients with BH4 deficiency, enzymes further are rate limiting in the biosynthesis of the sapropterin dihydrochloride is proposed to restore endog neurotransmitters serotonin (5-hydroxytryptamine), melato enous phenylalanine hydroxylase activity by providing an nin, dopamine, norepinephrine (noradrenaline), epinephrine exogenous source of the missing cofactor. (adrenaline), and nitric oxide (NO). 0010 Tetrahydrobiopterin is an unstable compound; at 0005. In order to control hyperphenylalaninemia caused ambient temperature it is prone to autoxidation in the pres due to both the conditions mentioned herewith above, dietary ence of molecular oxygen (Davis et al., Eur: J. Biochem., Vol intervention is followed. Such dietary intervention typically 173, 345-351, 1988). It also undergoes auto-oxidation in demand administering to the patient, food that is natural and aqueous solutions at pH 7.4 to form 7,8-dihydrobiopterin free from or low in phenylalanine. However such a dietary (BH2) (Thény et al., 2000). Tetrahydrobiopterin is also very regimen, apart from providing low phenylalanine, eliminates hygroscopic. Therefore the development of stable oral com many other sources of other essential amino acids, vitamins position comprising tetrahydrobiopterin that is prone to deg and minerals. Consequently such a diet provides inadequate radation at room temperature is a challenging task. protein, vitamins and minerals thereby hindering normal 0011. The formulation of KuvanTM as disclosed in the U.S. growth and development. Apart from adults, for babies too Pat. No. 7,566,462 describes use of polymorph B, of (6R)-L- infantformulae which have low phenylalanine content are the erythro-tetrahydrobiopterin dihydrochloride, an antioxidant, primary food source. The phenylalanine-free protein formu and a pharmaceutically acceptable excipient, diluent, or car lae that are available are mostly bitter tasting making the food rier for preparation of stable tablet formulation; wherein a US 2013/0336945 A1 Dec. 19, 2013 specific weight ratio of the antioxidant to the (6R)-L-erythro least one stabilizing agent. Particularly the present invention tetrahydrobiopterin dihydrochloride of about 1:5 to about relates to stable compositions of sapropterin dihydrochloride. 1:30 has been used. Such a composition after six months in a container at room temperature and about 60% humidity is DETAILED DESCRIPTION OF THE INVENTION said to retain at least about 95% of the initial amount of 0016. The present invention relates to stable compositions (6R)-L-erythro-tetrahydrobiopterin dihydrochloride. of tetrahydrobiopterin, processes for producing Such compo KuvanTM has a shelflife of 3 years when stored below 25°C. Further European Publication 1757293A1 discloses a phar sitions and methods of using Such compositions. Particularly maceutical preparation for the treatment of BH4-responsive the present invention relates to stable compositions compris hyperphenylalaninemia provided in the form of granule, fine ing tetrahydrobiopterin and at least one stabilizing agent. granule, or dry syrup, comprising sapropterin hydrochloride 0017 Tetrahydrobiopterin as employed in the composi as an active ingredient; a flavoring agent; a coloring agent tions of the present invention may be in the form of free base, which is stable to acid and oxidation; and ascorbic acid or free acid or pharmaceutically acceptable salts, prodrugs, pre L-cysteine hydrochloride as a stabilizer,