Abstract:
A method for reducing serum lipid levels in humans and animals is provided which comprises administering a hypolipidemically effective amount of p-chlorophenyl 2-(p-chlorophenoxy)-2-methylpropionate. A hypolipidemic composition is provided which comprises p-chlorophenyl 2-(p-chlorophenoxy)-2-methylpropionate, as principal active ingredient, in combination with a pharmaceutically acceptable carrier. Total serum lipids and serum cholesterol levels are significantly reduced.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to therapeutic applications in humans and animals of the p-chlorophenyl ester of p-chlorophenoxyisobutyric acid. 
     2. Description of the Prior Art 
     A number of esters and salts of clofibric acid and, in particular, the ethyl ester (clofibrate), the 3-dimethylcarbamoylpropyl ester (clofibride), and the aluminum, calcium and pyridoxine salts are used in therapy. We have now discovered that the p-chlorophenyl ester shows a very low toxicity and a hypolipidemic activity superior to that of clofibric acid and nicotinic acid. 
     The p-chlorophenyl ester of clofibric acid is a known chemical product (M. Julia et al, Bull. Soc. Chim. France, 1956, 776-83). Nevertheless, the therapeutic applications of this product have never before been described. 
     Both clofibric acid and nicotinic acid have been used as hypolipidemic agents, however a need continues to exist for hypolipidemic agents having even lower toxicity and higher activity than the above. 
     SUMMARY OF THE INVENTION 
     Accordingly, one object of the invention is to provide a hypolipidemic composition of low toxicity. 
     Another object of the invention is to provide a method of lowering serum lipid levels. 
     Briefly, these objects and other objects of the invention as hereinafter will become more readily apparent can be attained by providing a hypolipidemic composition which comprises p-chlorophenyl 2-(p-chlorophenoxy)-2-methylpropionate, as principal active ingredient, in combination with a pharmaceutically acceptable carrier; and a method of reducing serum lipid levels in humans or animals which comprises administering a hypolipidemically effective amount of p-chlorophenyl 2-(p-chlorophenoxy)-2-methylpropionate. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     The present inventors have now discovered that the p-chlorophenyl ester of clofibric acid shows a very low toxicity and a hypolipidemic activity significantly superior to that of both clofibric acid and nicotinic acid for reducing both total serum lipid levels and serum cholesterol levels. 
     The preparation of this ester may be performed according to classical methods. One example of this preparation is the following. 
     EXAMPLE 
     A mixture of 43 gm of p-chlorophenoxyisobutyric acid, 200 cc of benzene, and 40 cc of SOCl 2  is heated at reflux for 2 hours. The benzene and the thionyl chloride are evaporated until the temperature reaches 80° C. The resulting acid chloride of clofibric acid is vacuum distilled. B.p. 0 .4 mm =112° C. 
     To a mixture of 300 cc of benzene, 30 gm of triethylamine, and 26 gm of p-chlorophenol is added dropwise 40 gm of the acid chloride of clofibric acid. The temperature of the reaction mixture rises. The reaction mixture is stirred for 6 hours. The triethylamine hydrochloride is separated by filtration. The benzene phase is washed with cold dilute sodium hydroxide, and then washed with water. The benzene phase is dried and then evaporated. The residue is vacuum distilled to yield 43 gm of the ester, b.p. 0 .2 mm =165° C. The liquid so obtained is poured into a mortar. Crystallization is induced with a glass rod. The ester crystallizes in the form of a white solid, melting at 48° C. 
     The NMR spectrum is CDCl 3  (internal reference, TMS) shows a singlet centered at 1.7 ppm corresponding to the 6 methyl protons and a complex multiplet at 6.7-7.4 ppm corresponding to 8 aromatic protons. 
     PHARMACOLOGICAL STUDY 
     The acute toxicity of the p-chlorophenyl ester of clofibric acid was determined using two species of animals (Swiss EOPS mice and Wistar EOPS rats) by oral administration, the product being administered in a gum preparation. The animals were observed during 14 days. For the mice, a dose of 2000 mg/kg resulted in 10% mortality. For the rat, a dose of 2000 mg/kg did not result in any mortality, whereas the same dose of clofibric acid resulted in 40% mortality. 
     The hypolipidemic activity was determined in rats subjected to a regimen rich in lipids over the course of 2 sets of experiments. 
     1. Conventional male Wistar rats weighing 130-150 g were maintained on a regimen rich in lipids for 21 days. At the same time, beginning with the fifteenth day of the regimen, they received a daily dose of either a gum preparation containing the product to be tested or a preparation of 6% gum arabic alone. After a fast of 24 hours, the animals were sacrificed, 22 days after the start of the regimen. The results are presented in Table I. The percentage reductions of the lipid levels were calculated using the following equation: ##EQU1## 
     The reductions in blood and liver levels are significant only in the case of the p-chlorophenyl ester of clofibric acid. 
     2. Male Wistar EOPS rats weighing in the neighborhood of 140 g receive a regimen rich in lipids during 21 days. Beginning with the eleventh day, the animals receive either a gum preparation containing the product to be tested or a preparation of 6% gum arabic alone, for 6 days out of 7. After the last feeding, and a subsequent 24 hour fast, the animals are sacrificed. A group of animals submitted to a normal regimen is used as a control. The results are present in Table II. The percentage reductions of lipid levels are calculated using the following equation: ##EQU2## 
     
                                           TABLE I__________________________________________________________________________           SERUM                 LIVER           TOTAL LIPIDS                      CHOLESTEROL                                 TOTAL LIPIDS           concentration                  % re-                      concentration                             % re-                                 level in mg/g                                        % re-TREATMENT       in g/l duction                      in g/l duction                                 of liver                                        duction__________________________________________________________________________Normal regimen  3.53 ± 1.16                      0.85 ± 0.10                                 33.15 ± 12.54Regimen rich in lipids           5.32 ± 1.43                      2.41 ± 0.86                                 96.27 ± 19.26Regimen + nicotinic acid200 mg/kg/day1.626 mmole/kg/day           6.38 ± 1.55                      2.33 ± 0.67                              5  91.62 ± 19.94                                         7Regimen + p-chlorophenyl esterof clofibric acid200 mg/kg/day0.615 mmole/kg/day           3.87 ± 0.65                  81  1.33 ± 0.33                             69  60.82 ± 26.98                                        56__________________________________________________________________________ 
    
     
                                           TABLE II__________________________________________________________________________          SERUM LIVER                  Cholesterol        Choles-         Total lipids                  con-                      %              terol                                          Triglycerides         concen-               % re-                  cen-                      re-                          Triglycerides                                     level                                          level in         tration               duc-                  tration                      duc-                         concentra-                                Total                                     in mg/g                                          mg/g of                                               % re-                                                    Wt. of liverTREATMENT     in g/l               tion                  in g/l                      tion                         tion in g/l                                Lipids                                     of liver                                          liver                                               duction                                                    Wt of__________________________________________________________________________                                                    ratNormal regimen         2.24 ± 0.48                    0.70 0.55 ± 0.12                                22.2 4.4    14.20   2.90 ± 0.23                  ± 0.08     ± 5.9                                     ± 0.9                                          ± 4.62Regimen rich in lipids         7.26 ± 2.54                    4.17 0.63 ± 0.16                                285.2                                     121.6                                            31.74   5.71 ± 0.39                  ± 1.58     ± 52.5                                     ± 8.0                                          ± 4.58Regimen + p-chlorophenyl         5.56 ± 2.83               34   3.06                      32 0.39 ± 0.06                                323.9                                     123.0                                            23.37                                               48   6.08 ± 0.31ester         NS       ± 1.67                         S      ± 100.7                                     ± 20.2                                          ± 4.5775 mg/kg/day           NS                      S0,231 mmole/kg/dayRegimen + p-chlorophenyl         3.55 ± 0.77               74   1.79                      69 0.35 ± 0.06                                361.9                                     136.5                                            20.84                                               62   6.36 ± 0.31ester         S        ± 0.48                         S      ± 71.1                                     ± 14.3                                          ± 4.46125 mg/kg/day          S                       S0,384 mmole/kg/dayRegimen + p-chlorophenyl         3.81 ± 0.97               69   1.84                      67 0.22 ± 0.06                                382.0                                     135.2                                            16.20                                               89   6.70 ± 0.50ester         S        ± 0.44                         S      ± 54.6                                     ± 21.8                                          ± 2.27200 mg/kg/day          S                       S0,615 mmole/kg/dayRegimen + clofibric acid         4.97 ± 1.41               46   2.31                      54 0.23 ± 0.04                                382.7                                     127.0                                            20.33                                               65   6.99 ± 0.75125 mg/kg/day S        ± 0.68                         S      ± 43.5                                     ± 18.4                                          ± 2.680,515 mmole/kg/day     S                       S__________________________________________________________________________ The notations NS or S indicate the significance of the results obtained in the treated groups compared to the groups submitted only to a regimen rich in lipids. 
    
     At equal dosage levels, the p-chlorophenyl ester reduces serum lipid and cholesterol levels to a greater degree than the acid. These differences are significant. The weight of the animals&#39; livers increases using the p-chorophenyl ester but at equivalent dosage levels, the increase in weight is smaller than when the acid is used, and this difference is statistically significant. 
     A subchronic toxicity study of the p-chlorophenyl ester of clofibric acid was carried out using the following protocol. The product was administered six days a week during the course of a month, by oral administration in a gum preparation, to male Wistar EOPS rats having an average initial weight of 200 g. After the last feeding, the animals were fasted. A blood sample is taken from the abdominal aorta under anesthesia, then the animals are sacrificed. Table III shows the results of sampling the blood levels. The notation NS or S signifies whether the change induced by the product to be tested was statistically nonsignificant or significant. 
     In view of its pharmacological activity and its low toxicity, the p-chlorophenyl ester of p-chlorophenoxyisobutyric acid is therapeutically useful for treatment of lipid disfunction (hypercholesterolemia with or without xanthomatosis, hypertriglyceridemia, combined hyperlipidemia) as well as atherosclerotic conditions such as coronary insufficiency, cerebral vascular conditions, arteritis of inferior members, and arterial hypertension. 
     
                                           TABLE III__________________________________________________________________________                   ALKALINE        TOTAL          TRIGLY-      UREA  GLYCEMIA                   PHOSPHATASE                            BILIRUBIN                                   LIPIDS                                         CHOLESTEROL                                                  CERIDESTREATMENT  g/l   g/l    mU/ml    g/l    g/l   g/l      g/l__________________________________________________________________________Gum arabic 6%      0.46 ± 0.10            1.42 ± 0.26                   29.9 ± 6.6                            4.14 ± 1.24                                   3.82 ± 0.63                                         0.63 ± 0.11                                                  0.90 ± 0.16p-Chlorophenyl ester      0.42 ± 0.07            1.58 ± 0.15                   25.0 ± 4.9                            3.68 ± 0.73                                   2.92 ± 0.54                                         0.47 ± 0.04                                                  0.83 ± 0.27100 mg/kg/day      NS    NS     NS       NS     S     S        NSp-Chlorophenyl ester      0.34 ± 0.07            1.57 ± 0.15                   33.5± 7.8                            4.82 ± 1.85                                   2.54 ± 0.35                                         0.37 ± 0.07                                                  0.74 ± 0.1      S     NS     NS       NS     S     S        NSp-Chlorophenyl ester      0.40 ± 0.05            1.41 ± 0.26                   38.4 ± 9.9                            5.04 ± 1.09                                   2.77 ± 0.42                                         0.32 ± 0.06                                                  1.09 ± 0.33500 mg/kg/day      NS    NS     NS       NS     S     S        NS__________________________________________________________________________ 
    
     The active principle may be administered in association with appropriate vehicles and in various pharmaceutically acceptable forms, for example by oral administration in unit dosage form such as gels, capsules, tablets and lozenges at a dose of 0.1 to 2.5 g per day in 2 to 4 administrations per day.