WO2000062775A1

WO2000062775A1 - Compositions and methods for increasing the bioavailability of lactone ring containing drugs

Info

Publication number: WO2000062775A1
Application number: PCT/US2000/009989
Authority: WO
Inventors: Bert N. La Du; Scott S. Billecke; Raymond Counsel
Original assignee: University of Michigan System; University of Michigan Ann Arbor
Current assignee: University of Michigan System; University of Michigan Ann Arbor
Priority date: 1999-04-19
Filing date: 2000-04-14
Publication date: 2000-10-26
Anticipated expiration: 2001-10-19
Also published as: AU4348200A

Abstract

Compositions and methods are described for increasing the bioavailability of drugs, and in particular, drugs and prodrugs containing lactone structures which are hydrolyzed to open forms (carboxylic acids and alcohols) by serum and tissue paraoxonase. Inhibitors of paraoxonase (e.g. lactams) are co-administered with such drugs, thereby preventing paraoxonase from acting on these lactone substrates. Such inhibitors are particularly suitable in conjunction with the administration of lovastatin, simvastatin or mevastatin.

Description

COMPOSITIONS AND METHODS FOR INCREASING THE BIOAVAILABILITY OF LACTONE RING CONTAINING DRUGS

FIELD OF THE INVENTION

The present invention relates to compositions and methods for increasing the bioavailability of drugs, and in particular, drugs and prodrugs containing lactone structures which are hydrolyzed to open forms (carboxylic acids and alcohols) by serum and tissue paraoxonase.

BACKGROUND

Coronary artery disease, the primary form of cardiovascular disease, is the major cause of death in the United States today, responsible for over 550,000 deaths per year. Cerebrovascular disease is the third leading cause of death in the United States. The etiology of both coronary artery and cerebrovascular diseases is attributed to atherosclerosis. Through its clinical manifestations, atherosclerosis is the major cause of the more than one million heart attacks and approximately 400,000 strokes that occur each year. In addition to the high morbidity and mortality associated with atherosclerosis, it has been estimated that atherosclerosis has cost the United States' economy over $80 billion each year in lost wages, lost productivity, and medical care costs. Levy, Am. Heart J., 110:1116 (1985).

A substantial body of evidence has established a causal relationship between hypercholesterolemia and premature atherosclerosis; the higher the levels of plasma cholesterol, the greater the risk of subsequent heart attack. Steinberg, JAMA 264:3047 (1991); Lipid Research Clinics Program, JAMA 251:351 (1984); Rifkind, Am. J. Cardiol, 54: 30C (1984).

A number of drugs are available for treating hypercholesterolemia. Many of these drugs target hydroxymethylglutaryl coenzyme A (HMG-CoA) reductase, which catalyzes the conversion of hydroxymethylglutaryl (HMG) to mevalonate. This step is an early and rate-limiting step in cholesterol synthesis. Brown et al, J. Lipid Research 21: 507-17 (1980). These drugs include the structurally related lactones: lovastatin, simvastatin, and pravastatin. Hamelin et al., Trends Pharmacol Sci., 19(l):26-37 (1998). Lovastatin is derived from a fungal source and simvastatin and mevastatin are modifed lovastatin. Simvastatin is administered as a lactone prodrug. The metabolized form, β- hydroxyacid-simvastatin is the most potent form with respect to HMG-CoA reductase inhibition. Todd et al., Drugs, 40(4): 583-607 (1990). After administration to humans, simvastatin undergoes extensive first pass metabolism in the liver, the primary site of action, and is excreted into the bile. This is due to the conversion of the lipophilic lactone form to the hydrophihc β-hydroxyacid form, which is three orders of magnitude less lipophilic than the lactone form. The hydrophihc β-hydroxyacid form is not able to cross cell membranes as easily as the lipophilic lactone form. As a result, the absolute bioavailability of simvastatin is less than 5%.

Therefore, what is needed in the art are more effective treatments for hypercholesterolaemia and atherosclerosis. In particular, what is needed is a method to increase the bioavailability of lactones such as simvastatin, so that less simvastatin need be administered.

SUMMARY OF THE INVENTION

The present invention relates to compositions and methods for increasing the bioavailability of drugs, and in particular, drugs and prodrugs containing lactone structures which are hydrolyzed to open forms (carboxylic acids and alcohols) by serum and tissue paraoxonase. The present invention contemplates that bioavailability can be enhanced by inhibiting paraoxonase (and other enzymes which act on lactones as substrates). Such inhibition can be achieved by administering an inhibitor of such an enzyme to the drug recipient i) prior to acn inistration of the drug, ii) after administration of the drug, or iii) simultaneously (or essentially simultaneously) with the drug. In the latter case, simultaneous administration can be achieved by mixing the inhibitor together with the drug to create a mixture, and then administering the mixture. In another embodiment, the inhibitor is mixed with the drug as it is administered. In still another embodiment, the inhibitor is not mixed but is simply given at the same time that the drug is administered. Thus, simultaneous administration can be achieved by a variety of methods and need not involve the same route of administration (e.g. the drug might be given orally and the inhibitor might be given intraveneously).

It is not intended that the present invention be limited to particular drug for which enhanced bioavailability is sought. The present invention contemplates that the lactone substrates vary in ring size from four to seven (with some even larger), with a variety of substituents on the ring carbons. By way of example only, substrates include homogentisic acid lactone, mevalonic acid lactone and γ-hydroxybutyric acid lactone. Other examples include the macrolide antibiotics, of which erythromycin is one example (having a 14-membered lactone ring).

It is also not intended that the present invention be limited to the particular inhibitor. A variety of inhibitors are contemplated. In one embodiment, the present invention contemplates cyclic amides as inhibitors, and more specifically lactams. By way of example only, the present invention contemplates ε-caprolactam. In another embodiment, the present invention contemplates oxindole, a naturally occurring compound derived from the amino acid tryptophan, as an inhibitor that can be administered to enhance the bioavailability of a drug. Even more potent inhibitors include isatin and 2-hydroxyquinoline.

The present invention contemplates both compositions and methods. For example, the present invention contemplates a composition comprising a drug containing a lactone structure and an inhibitor of paraoxonase. The present invention also contemplates a method. In one embodiment, the method comprises a) providing i) a drug recipient, ii) a drug containing a lactone structure, and iii) an inhibitor of paraoxonase; and b) administering said drug and said inhibitor to said drug recipient The drug recipient can be an animal or a human. The drug and inhibitor can be in a mixture or can be administered as described above. When in a mixture, both aqueous mixtures and tablets (including suppositories) are contemplated. In one embodiment, said drug containing a lactone structure is selected from the group consisting of lovastatin, simvastatin and mevastatin. In this embodiment, the preferred inhibitor is N-bromo-epsilon-caprolactam (although other inhibitors disclosed herein can also be used). In another embodiment, said drug containing a lactone structure is selected from the group consisting of angelicalactone, γ-butyrolactone, decanolactone, thiobutyrolactone, spironolactone.

The present invention contemplates lactams as inhibitors. In one embodiment, said inhibitor is selected from the group consisting of isatin, ε-caprolactam and 2- hydroxyquinoline. In another embodiment, the inhibitor comprises oxindole.

DEFINITIONS

As used herein, "administering essentially simultaneously" or the like is meant to indicate that a recipient is administered a drug and inhibitor within minutes or even hours (but not days) of one another. For example, the present invention contemplates administering essentially simultaneously by administering the inhibitor up to one hour prior to the administration of the drug.

As used herein "lactone structures" is meant to indicate cyclic esters varying in ring size from four to seven, and more preferably encompassing five-membered cyclic esters (or γ-lactones) and six-membered cyclic esters (or δ-lactones).

As used herein "lactam" is mean to indicate a cyclic amide. As used herein "drug recipients" are live animals or humans who are to be administered a drug.

DESCRIPTION OF THE DRAWINGS

Figure 1 shows the substrates for paraoxonase, including a lactone substrate. Figure 2 shows the lactone substrates lovastatin, simvastatin and mevastatin. Figure 3 shows the prodrug substrate NM441.

Figure 4 shows an illustrative group of inhibitors of paraoxonase. DESCRIPTION OF THE INVENTION

The present invention relates to compositions and methods for increasing the bioavailability of drugs, and in particular, drugs and prodrugs containing lactone structures which are hydrolyzed to open forms (carboxylic acids and alcohols) by serum and tissue paraoxonase. Many drugs are administered in lactone form. The lactone conformation of said drugs, however, is often not the active form of the drug. Typically, the ring structure of such administered drugs needs to be opened before they exert an intracellular effect. That is to say, the pharmacologically active form of these drugs is generally the open form. However, the open form does not penetrate membranes well or distribute efficiently from blood serum to the tissues. In contrast, the lactone form distributes through membranes and tissues.

The present inventors have discovered that lactones are a substrate for serum paraoxonase (PONl), an enzyme that selectively cleaves the ring structure of lactones. The intracellular bioavailability of lactone drugs are severely reduced by circulating serum PONl which cleaves said lactones into an open form, thereby, precluding access to the cell. Since the open form of most drugs administered in a lactone form are the therapeutically active conformation, the present invention contemplates compounds and methods for inhibiting PONl to increase the bioavailability of lactones.

1. Functional Characteristics of Paraoxonase Paraoxonase is a calcium-dependent esterase that is known to catalyze a variety of substrates, including aromatic esters and organophosphates. The present invention adds lactones to this group (Figure 1). Paraoxonase has been found in a variety of mammalian tissues, with liver and serum having the highest levels. See, Aldridge, Serum Esterases: I., An enzyme hydrolyzing diethyl p-nitrophenyl phosphate (E600) and its identity with the A-esterase of mammalian sera. Biochem J 53: 117-124

(1953). Candidate inhibitors can be screened against different paraoxonases with success. The preferred forms for such screening are the human form or the rabbit paraoxonase. See Kuo. et al., "Comparison of purified human and rabbit serum paraoxonases," Drug Metab. Dispos 23: 935-944. 2. Structural Diversity of Human Paraoxonases

Human serum paraoxonase (PON 1) is a polymorphic enzyme, occurring as two forms that differ only by the amino acid at position 191, which is glutamine in type Q (formerly type A) and arginine in type R (type B). See B. La Du, "Structural and functional diversity of paraoxonases," Nature Med. 2:1186 (1996). The PONl R variant has 8 times the activity against paraoxon than the Q allozyme has, but the two forms are similar in their ability to hydrolyze a reference aromatic ester, phenyl acetate. Both of the forms of paraoxonase are contemplated as useful for screening candidate inhibitors.

3. Pre-screening Recipients of Inhibitors

The human population shows some variability in serum paraoxonase levels and activity. To select the appropriate dosage of an inhibitor, the present invention contemplates first pre-screening individuals who will be receiving paraoxonase inhibitors for serum paraoxonase levels. This is done by obtaining serum or heparinized plasma by venipuncture (to avoid inactivation of the enzyme, samples should not be collected in EDTA-containing vacutainers).

To assay, 5 μl of serum is added to a 0.800-ml mixture of 1.0 mM paraoxon (Sigma, St. Louis, MO) and 1.0 mM CaCl₂ in 0.05 M glycine buffer, pH 10.5 [16], lacking added NaCl. The liberation of p-nitrophenol upon enzymatic hydrolysis of paraoxon was followed at 412 nm (E_M= 18,290) in a dual beam recording spectrophotometer (DBG, Beckman, Irvine, CA), maintained at 25°C. The rate of nonenzymatic hydrolysis of paraoxon was corrected for by using an appropriate reference cuvette without added serum. Routinely, no correction was made for the non-EDTA inhibitable serum paraoxonase activity because preliminary experiments showed that this was significant only in samples having extremely low activity. One unit (U) of paraoxonase activity is defined as 1 μmol of^-nitrophenol formed per min, and activity was normally expressed as U/l of serum. Paraoxon was stored at -20°C as a stock solution of approximately 0.5 M in methanol, and a portion was diluted daily to 4.0 mM in water. The accuracy of this daily stock dilution was assured by measuring p-nitrophenol liberated by the complete hydrolysis of paraoxon by base. A portion of the daily stock was diluted 1:100 with 1.0 M NaOH, heated for 5 min at 100°C, and p-nitrophenol determined by the additional absorbance at 412 nm. The concentration of paraoxon was then adjusted as needed to 4.0 mM . The concentration of methanol in the assay, 0.2%, did not significantly inhibit serum paraoxonase.

Basal paraoxonase activity is that measured without added NaCl to the assay. Salt-stimulated paraoxonase activity was that measured with 1 M NaCl in the standard assay in which NaCl was added to both the enzymatic and reference cuvettes. The degree of salt stimulation was expressed as:

Paraoxonase activity with 1 M NaCl - Basal paraoxonase activity _{1 /vw} X IUUTO.

Basal paraoxonase activity

In certain experiments on paraoxonase activity, with pH 8.0 Tris/HCl or pH 7.2 triethanolamine was used as the buffer. The pH 7.2 assay with triethanolamine contained 10 mM CaCl₂, which duplicated the procedure of Zech and Zurcher [7]. The molar extinction coefficient of p-nitrophenol released at pH 8.0 was 16,700, and at pH 7.2, 14,000. In other respects, the assays were as described above for pH 10.5.

4. Screening Candidate Inhibitors

The present invention contemplates testing candidate compounds for inhibition of paraoxonase. Inhibition can be tested using serum samples of the enzyme (as described above). Alternatively, purifed paraoxonase can be used. The table below shows the results of such testing.

The following are all lactam inhibitors of PON. The approximate Ki values given are for inhibition of ImM phenyl acetate activity when using purified human seram PON type Q.

Lower Ki values represent a greater degree of inhibition.

Inhibitor Reversible? Ki fμMϊ

3 ,4-dihydro-2( 1 H)-quinolinone Yes Less than 25

2-hydroxyquinoline Yes Less than 5

Oxindole Yes 50

Delta Valerolactam Yes 500

Epsilon-Caprolactam Yes 100

Isatin Probably not Very Potent

N-Bromo-Epsilon-Caprolactam No Very Potent 5. Drugs as Substrates for Paraoxonase

The present invention contemplates that inhibitors of paraoxonase can be administered to increase the bioavailability of drugs, and in particular, drugs and prodrugs containing lactone structures which are hydrolyzed to open forms (carboxylic acids and alcohols) by serum and tissue paraoxonase. It is not intended that the present invention be limited to the particular drug for which the administration (e.g. co-administration) of an inhibitor is selected. By way of example, Figure 2 shows the drugs lovastatin, simvastatin and mevastatin as drugs contemplated by the present invention for which co-administration of an inhibitor is suitable. By way of an additional example, Figure 3 shows the prodrug substrate NM441 as a drug for which co-administration of an inhibitor is suitable..

6. Inhibitors

The present invention contemplates a variety of inhibitors of paraoxonase. It is not intended the present invention be limited to a specific paraoxonase inhibitor. In a preferred embodiment, however, said paraoxonase inhibitor is a lactam. Preferred lactams include, but are not limited to, the lactams presented in Figure 4. (e.g., delta valerolactam, epsilon-caprolactam, and N-bromo-epsilon-caprolactam). All of the above referenced compounds are commercially available from such suppliers such as Aldrich (Milwaukee, WI). The prior art is silent on the use of lactams as paraxonase inhibitors in methods for increasing the bioavailability of drugs acirninistered as lactones. However, the use of some of the above captioned compounds in unrelated therapeutic applications has been documented, thereby, demonstrating the relative biocompatibility of these compounds. For example, the prior art reports the use of genetic activity profiles to present quantitative short-term test data to evaluate caprolactam. See Brady et al., "The Genetic Toxicology of Benzoin and Caprolactam," Mutation Research, 224: 391-403 (1989). Caprolactam does not induce DNA damage, gene mutation, sister-chomatid exchange, micronuclei, chromosomal aberrations or aneuploidy in mammalian cells in culture. However, chromosomal aberrations were reported in a single study in Chinese hamster lung fibroblasts in the presence of an exogenous metabolic system. Brady et al. report that, overall, the overwhelming majority of short-term test data suggest that (in accordance with animal cancer data) caprolactam is not genotoxic. Id at 400. In terms of physiological toxicity, epsilon-caprolactam has been reported to produce a nonsedating rotorod toxicity at a dose of 300mg/kg in mice. Reddy et al., "Synthesis and Anticonvulsant Activities of 3,3-Dialkyl- and 3-Alkyl-3-benzyl-2-piperidinones (δ-Valerolactams) and Hexahydro-2H-azepen-2-ones (ε -Caprolactams)," J. Med. Chem., 40:44-49 (1997). The prior art describes the anticonvulsant effects of various δ-valerolactams.

Specifically, 3,3-diethyl-2-piperidinone is an effective anticonvulsant against pentylenetetrazole-induced (PTZ) seizures (ED₅₀, 37 mg/kg; PI (TD₅₀/ED₅₀), 4.46) wherein ED^ designates anticonvulsant potencies against pentylenetetrazole and maximal electrical shock (MES) induced seizures in mice, TD₅₀ denotes neurotoxicity as evaluated by a rotorod test, and PI denotes the protective index for the δ- valerolactam tested. By comparison phenobarbital (a known sedative anticonvulsant and hypnotic) presented the following profile for PTZ induced seizures: ED₅₀ 22 mg/kg; PI (TD₅₀/ED₅₀), 4.00. Similarly, 3-(Phenylmethyl)-2-piperidinone is an effective anticonvulsant against MES induced seizures (ED₅₀, 41 mg/ml; PI, 7.05). By comparison phenobarbital presented the following profile for MES induced seizures:

ED₅₀ 17 mg kg; PI (TD₅₀/ED₅₀), 5.18). Reddy et al, "Synthesis and Anticonvulsant Activities of 3,3-Dialkyl- and 3-Alkyl-3-benzyl-2-piperidinones (δ-Valerolactams) and Hexahydro-2H-azepen-2-ones (ε -Caprolactams)," J. Med. Chem., 40:44-49 (1997).

Oxindole is a neurodepressant tryptophan metabolite physiologically present in mammalian brain and blood. See Mannaino et al., "Electrophysiological Studies Of

Oxindole, A Neurodepressant Tryptophan Metabolite," British Journal of Pharmacology, 125: 1751, 1755, (1988). When administered to rats at a dose of lOmg kg^"1 (intraperitoneal), oxindole exhibits anticonvulsant and sedative properties lasting for a period of at least 30 min. Id at 1753. Steady state (e.g., without exogenous oxidole administration) oxidole concentrations in rat brain tissue has been measured at 0.05 (+/-) 0.01 nmol g^"1. Id. One hour after administration of a dose of lOmg/Kg^"1 (intraperitoneal) said oxidole tissue concentration increased to 8.1(+/) 1.7 nmol g^"1. Id. Isatin is a known inhibitor of liver xanthine oxidase and kidney alkaline phosphatase from rat. The prior art also reports the use of isatin for studying the organ and species specificity of alkaline phosphatase. Specifically, isatin has been found to inhibit rat testicular alkaline phosphatase. See Kumar et al., "Nature of Rat Testicular Alkaline Phosphatase by Isatin," Experientia 15;34(4), 434-5 (April, 1978). In addition, the binding of isatin to human serum albumin has also been studied (in vitro) by equilibrium dialysis and ultrafiltration. Maysinger et al, "Binding (in vitro) of some antimitotic isatin derivatives to human serum albumin," Chemotherapy, 27(2):80-4 (1981).

7. Formulations and Routes of Administration

The present invention is not limited by the method of administration of drugs and or inhibitors. For example, it is contemplated that the inhibitors of the present invention be administered alone or can be administered with a pharmaceutical carrier selected on the basis of the chosen route of admimstration and standard pharmaceutical practice. In one embodiment, inhibitors (or mixtures of inhibitors and drugs) are administered orally in solid dosage forms, such as capsules, tablets, or powders, or in liquid dosage forms, such as elixirs, syrups, and suspensions; however, it can also be administered parenterally, in sterile liquid dosage forms, or rectally in the form of suppositories.

One skilled in the art will be capable of adjusting the administered dose depending upon known factors such as the mode and route of administration; age, health, and weight of the recipient; nature and extent of symptoms, kind of concurrent treatment, frequency of treatment, and the effect desired. However, the present invention contemplates that less drug will be effective when co-administered with an inhibitor of the present invention. Additionally, inhibitors can be employed in admixture with conventional excipients, i.e., pharmaceutically acceptable organic or inorganic carrier substances suitable for parenteral (e.g., topical application) or enteral (e.g., oral) which do not deleteriously react with the active compounds. Suitable pharmaceutically acceptable carriers include but are not limited to water, salt solutions, alcohols, gum arabic, vegetable oils, benzyl alcohols, polyethylene glycols, gelatine, carbohydrates such as lactose, amylose, or starch, magnesium stearate, talc, silicic acid, viscous paraffin, perfume oil, fatty acid monoglycerides and diglycerides, pentaerythritol fatty acid esters, hydroxy methylcellulose, polyvinyl pyrrolidone, merely to name a few. The pharmaceutical preparations can be sterilized and if desired mixed with auxiliary agents, e.g., lubricants, preservatives, stabilizers, wetting agents, emulsifier, salts for influencing osmotic pressure, buffers, coloring, flavoring, and/or aromatic substances and the like which do no deleteriously react with the active compounds. They can also be combined where desired with other agents, e.g. vitamins.

For enteral application, particularly suitable are tablets, liquids, drops, suppositories, or capsules. A syrup, elixir, or the like can be used wherein a sweetened vehicle is employed. Sustained or directed release compositions can be formulated, e.g., liposomes or those wherein the active compound is protected with differentially degradable coating, e.g., by microencapsulation, multiple coatings, etc.

In this manner, the present invention may be introduced into a subject in polymeric microspheres for the controlled release of the compound. Methods of producing microspheres from polymer can be found in U.S. Patent No. 5,601,844 to Kagayama, et al. and U.S. Patent Nos. 5,529,914 and 5,573,934 to Hubbel, et al, herein incorporated by reference.

For parenteral application, particularly suitable are injectable, sterile solutions, preferably oily or aqueous solutions, as well as suspensions, emulsions, or implants including suppositories. Nebulizers and inhalation aerosols may also be used. Ampules are in convenient unit dosages. For other parenteral applications, such as topical applications and non-sprayable forms, viscous to semi-solid or solid forms comprising a carrier compatible with topical application and having a dynamic viscosity preferably greater than water. Suitable formulations include but are not limited to transdermal patches, solutions, suspensions, emulsions, creams, ointments, powders, liniments, salves, aerosols, etc., which are, if desired, sterilized or mixed with auxiliary agents, e.g., preservations, stabilizers, wetting agents, buffers, or salts for influencing osmotic pressure, etc.

Also suitable for topical application are sprayable aerosol preparations wherein inhibitors, preferably in combination with a solid or liquid inert carrier material, is packaged in a squeeze bottle or in admixture with pressurized volatile, normally gaseous propellant, e.g., a freon. The application of these embodiments can be to the skin or mucous membrane or in the interior of the body and can be oral, peroral, enteral, pulmonary, rectal, nasal, vaginal, lingual, intervenous, intraarterial, intracardial, intramuscular, intraperitoneal, intracutaneous, subcutaneous. The parenteral preparations are preferably sterile or sterilized products.

In this manner, U.S. Patent No. 4,895,727 to Allen, herein incorporated by reference, describes a method of inducing a reservoir effect in skin and mucous membranes so as to enhance penetration and retention and reduce transdermal flux of topically applied therapeutic and cosmetic pharmacologically active agents. U.S. Patent No. 4,557,934 to Cooper, herein incorporated by reference, describes topical pharmaceutical compositions containing a pharmaceutically-active agent and the penetration enhancing agent, l-dodecylazacycloheptan-2-one. This composition provides marked transepidermal and percutaneous delivery of the selected pharmaceutically-active agent. Suppositories containing inhibitors (or mixtures of inhibitors and drugs) can be created using a suitable oleaginous or water-soluble base. The oleaginous class includes cocoa butter and fats with similar properties: the water-soluble class includes polyethylene glycols.

Other medicaments containing inhibitors can be produced in a known manner, whereby the known and customary pharmaceutical adjuvants as well as other customary carrier and diluting agents can be used. Examples include, but are not limited to, gelatins, natural sugars such as sucrose or lactose, lecithin, pectin, starch (for example comstarch), alginic acid, tylose, talc, lycopodium, silica (for example colloidal silica), glucose, cellulose, cellulose derivatives for example, cellulose ethers in which the cellulose hydroxyl group are partially etherified with lower aliphatic alcohols and/or lower saturated oxyalchohols, for example, methyl hydroxypropyl cellulose, methyl cellulose, cellulose phthalate, stearates, e.g., methylstearate and glyceryl stearate, magnesium and calcium salts of fatty acids with 12 to 22 carbon atoms, especially saturated acids (for example, calcium stearate, calcium laurate, magnesium oleate, calcium palmitate, calcium behenate and magnesium stearate), emulsifiers, oils and fats, especially of plant origin (for example, peanut oil, castor oil, olive oil, sesame oil, cottonseed oil, com oil, wheat germ oil, sunflower seed oil, cod-liver oil), mono, di, and triglycerides of saturated fatty acids (C₁₂ H₂₄ O₂ to C,gH₃₆O₂ and their mixtures), e.g. glyceryl monostearate, glyceryl distearate, glyceryl tristearate, glyceryl trilaurate), pharmaceutically compatible mono- or polyvalent alcohols and polyglycols such as glycerine, mannitol, sorbitol, pentaerythritol, ethyl alcohol, diethylene glycol, triethylene glycol, ethylene glycol, propylene glycol, dipropylene glycol, polyethylene glycol 400, and other polyethylene glycols, as well as derivatives of such alcohols and polyglycols, esters of saturated and unsaturated fatty acids (2 to 22 carbon atoms, especially 10 to 18 carbon atoms), with monohydricaliphatic alcohols (1 to 20 carbon atom alkanols), or polyhydric alcohols such as glycols, glycerine, diethylene glycol, pentaerythritol, sorbitol, mannitol, ethyl alcohol, butyl alcohol, octadecyl alcohol, etc., e.g. glyceryl stearate, glyceryl palmitate, glycol distearate, glycol dilaurate, glycol diacetate, monoacetin, triacetin, glyceryl oleate, ethylene glycol stearate; such esters of polyvalent alcohols can in a given case be etherified, benzyl benzoate, dioxolane, glycerine formal, tefrahydrofurfuryl alcohol, poly glycol ethers with 1 to 12 carbon atom alcohols, dimethyl acetamide, lactamide, lactates, e.g., ethyl lactate, ethyl carbonate, silicones (especially middle viscosity dimethyl polysiloxane). Other adjuvants can also be substances which bring about decomposition (so-called explosives) such as: cross-linked polyvinyl pyrrolidone, sodium carboxy methyl starch, sodium carboxy methyl cellulose or microcrystalline cellulose. Likewise, known coating agents such as e.g. polyacrylates, cellulose ethers and the like can be used.

For the production of solutions, there can be used water of physiologically compatible organic solvents, as for example, ethanol, 1,2-propylene glycol, polyglycols, e.g., diethylene glycol, triethylene glycol and dipropylene glycol and their derivatives dimethyl sulfoxide, fatty alcohols, e.g., stearyl alcohol, cetyl alcohol, lauryl alcohol and oleyl alcohol, triglycerides, e.g. glyceryl delate glyceryl stearate, glyceryl palmitate, and glyceryl acetate, partial esters of glycerine, e.g., glyceryl monostearate, glyceryl distearate, glyceryl monopalmitate, paraffins, and the like.

For injectable solutions or suspensions, non-toxic parenterally compatible diluting agents or solvents can be used, for example: Water, 1,3 butane diol, ethanoL 1,2-propylene glycol, polyglycols in a mixture with water, Ringer's solution, isotonic solution of sodium chloride or also hardened oils including synthetic mono or diglycerides or fatty acids like oleic acid.

Known and customary solution assistants or emulsifiers can be used in the production of the preparations. The following are examples of solution assistants and emulsifiers which can be used: Polyvinylpyrrolidone, sorbitan fatty acid esters such as sorbian trioleate, phosphatides such as lecithin, acacia, tragacath, polyoxethylated sorbitan monooleate and other ethoxyated fatty acid esters of sorbitan, polyoxyethylated fats, polyoxyethylated oleotriglycerides, linolized oleotriglycerides, polyethylene oxide condensation products of fatty alcohols, alkyl phenolene or fatty acids or also l-methyl-3-(2-hydroxyethyl)imidazolidone-(2). The term polyoxyethylated means in this context that the substances in question contain polyoxyethylene chains whose polymerization is generally between 2 to 40 and especially between 10 to 20.

Such polyoxyethylated substances can be obtained, for example, by reacting compounds containing hydroxyl groups (e.g. mono or diglycerides or unsaturated compounds such as, e.g., those containing the oleic acid residues) with ethylene oxide (e.g. 40 moles ethylene oxide per mole glyceride). Examples of oleotriglycerides are olive oil, peanut oil, castor oil, sesame oil, cotton seed oil and corn oil. [See also Fiedler, Lexicon der Hilfastoffe fur Pharmazie, Kosmetik and angrezende Gebiete [Lexicon of Adjuvants for Pharmacy, Cosmetics an Related Areas] pp. 191-195

(1971)].

Furthermore, there can be added preservatives stabilizers, buffers, for example, calcium hydrogen phosphate, colloidal aluminum hydroxide, taste correctives, antioxidants and complex formers (for example, ethylene diamine tetraacetic acid) and the like. In a given case for stabilization of the active molecule, the pH is adjusted to about 3 to 7 with physiologically compatible acids or buffers. Generally, there is preferred as neutral as possible to weak acid (to pH 5) pH value.

As antioxidants, there can be used, for example, sodium metabisulfite, ascorbic acid, gallic acid, alkyl gallates, e.g., methyl gallate and ethyl gallate, butyl hydroxyanisole, nordihydroguararetic acid. As preservatives, there can be used, for example, sorbic acid, p-hydroxybenzoic acid esters (for example, lower alkyl esters such as the methyl ester and the ethyl ester) benzoic acid, sodium benzoate, trichloroisobutyl alcohol, phenol, cresol, benzethonium chloride, and formalin derivatives.

EXPERIMENTAL

The following examples serve to illustrate certain preferred embodiments and aspects of the present invention and are not to be construed as limiting the scope thereof.

EXAMPLE 1 Treating Coronary Heart Disease with Simvastatin and PONl Inhibitors

The benefit of administering Simvastatin in conjunction with the compositions of the present invention to treat Coronary Heart Disease is demonstrated in the following example. People at increase risk for atherosclerotic vascular disease due to hypercholesterolemia are orally administered Simvastatin in conjunction with one or more inhibitors of paraoxonase.

Treatment with the Simvastatin and the compositions of the present invention is provided as an adjunct to diet for the reduction of elevated Low Density Lipid (LDL) cholesterol levels in patients with hypercholesterolemia (Types Ila, lib and III).

Simvastatin and the compositions of the present invention are provided when the response to a low cholesterol and saturated fat diet is inadequate. Prior to initiating therapy, alternative causes for hypercholesterolemia (e.g. poorly controlled diabetes mellitus, hypothyroidism, nephrotic syndrome, dysproteinemias, obstructive liver disease, other drug therapy, and alcoholism) should be excluded. Additionally, a lipid profile should be performed to measure TOTAL-C, HDL-C, and triglycerides in order to determine LDL concentrations.

The effective starting dose for Simvastatin in conjunction with the compositions of the present invention is 0.01-5.0 mg q.p.m.once a day in the evening. This amount may be increased (e.g. up to 35 mg q.p.m. per day) depending on the patient's response to treatment. However, the present invention contemplates that less simvastatin can be used when co-administered with one or more inihibitors of the present invention than currently used clinically, because of the enhanced bioavailability achieved with the inhibitors.

EXAMPLE 2

Treating Disease in Humans with Spironolactone and PONl Inhibitors

The following example demonstrates the benefits of administering Spironolactone in conjunction with compositions of the present invention. Administering Spironolactone in conjunction with the inhibitors of the present invention has many useful applications in diagnosing and treating diseases such as primary hyperaldosteronism, edema, hypertension, and hypokalemia.

Treatment with Spironolactone in conjunction with the compositions of the present invention is used as therapy for primary hyperaldosteronism. Diagnosis of the disease is achieved by employing a long test or short test. The long test employs a daily dosage of 400 mg (or less) for three to four weeks. Presumptive evidence of primary hyperaldosteronism is indicated if hypokalemia and hypertension is corrected in the patient. The short test employs a daily dosage of 400 mg for four days. If serum potassium increases during treatment, but drops when treatment is discontinued, a presumptive diagnosis of primary hyperaldosteronism is indicated. A diagnosis of hyperaldosteronism is followed by the administration of 100-400 mg (or less) of Spironolactone in conjunction with the compositions of the present invention in preparation for surgery. Patients not suitable for surgery, or who opt against it, are administered long term therapy of Spironolactone and the compositions of the present invention at the lowest effective dosage for the individual patient.

Treatment with Spironolactone in conjunction with the compositions of the present invention is used as therapy for patients with edematous conditions (i.e. used as a diuretic). Edema is caused by diseases such as congestive heart failure, cirrhosis of the liver, and nephrotic syndrome. Edema is treated with an initial dose of 100 mg (or less) of Spironolactone in conjunction with the compositions of the present invention. This treatment is continued for five days or until the desired diuretic affect is achieved. A second diuretic should be added to this treatment if an adequate response is not achieved in five days.

Treatment with Spironolactone in conjunction with the compositions of the present invention is used as therapy for Essential Hypertension. An initial daily dosage of 50 to 100 mg of Spironolactone (or less) in conjunction with the compositions of the present invention is employed. Treatment is continued for at least two weeks, as the maximum response may not occur before this. Treatment may also be in combination with other antihypertensive drugs or diuretics. Treatment with Spironolactone in conjunction with the compositions of the present invention is used as therapy for Hypokalemia. A dosage of 100 mg daily of Spironolactone (or less) in conjunction with the compositions of the present invention are employed in this therapy. This type of treatment is especially useful when potassium supplements or other potassium-sparing regimens are considered inappropriate. In all of these applications, the present invention contemplates that less Spironolactone can be used when co-administered with one or more inihibitors of the present invention than currently used clinically, because of the enhanced bioavailability achieved with the inhibitors.

EXAMPLE 3

Biodegradable Drug Delivery Using t-CaproIactone and PONl Inhibitors

Biodegradable drug delivery material is synthesized employing (poly) epsilon- Caprolactone (PCL) and the compositions of the present invention. This biomaterial optionally incorporates other copolymers such as (poly) lactic acid, (poly) lactic-co- glycolic acid, and (poly) lactide. This biomaterial is mixed with one or more therapeutic agents to form a drug delivery system. Various methods for manufacturing this biomaterial are employed. Examples include solvent casting (for microspheres), solvent casting particulate leaching (for microspheres), interfacial deposition techniques (for nanocapsules), nanoprecipitation (for nanoparticles), solvent evaporation (for mirosperes), and melt encapsulation (also for microspheres). This biomaterial is administered to patients to provide sustained release of the therapeutic agents.

EXAMPLE 4 Anticonvulsant Treatment Provided by Decanolactone and Inhibitors

Anticonvulsant treatment is demonstrated by administering Decanolactone to mice. Adult (20-35g) albino male mice are given 90 mg/kg Pentylenetetrazol (PTZ) subcutaneously in order to induce convulsions. Providing intraperitoneal or oral administration of γ-decanolactone thirty minutes prior to PTZ admimstration prevents convulsions. Souza et. al., J. of Ethnopharmacology, 58:175-181 (1997) herein incorporated by reference. Therefore, it is desirable to administer Decanolactone in conjunction with the PONl inhibitors of the present invention to prevent convulsions.

Accordingly, the ED₅₀ for intraperitoneal administration of Decanolactone is 90-350 mg/kg, and the ED₅₀ for oral administration is 600-5000 mg kg to prevent convulsions in mice. It is expected that the ED₅₀ is reduced for mice when Decanolactone is co- administered with the PONl inhibitors of the present invention. Administration of Decanolactone in conjunction with the compositions of the present invention could be extended to human therapy using techniques known to those skilled in the art.

EXAMPLE 5 Administration of Angelicalactone and Inhibitors Increases GST Levels

Administering α -Angelicalactone leads to an increase in the levels of glutathione S-transferases (GSTs) in rats. Male Wistar rats (aprox. 243g) are fed .5% w/w α-Angelicalactone in their diet, which leads to a substantial increase in the level of GSTs expressed in various organs (e.g. oesophagus, stomach, small intestine, and liver). Nijhoff et al, Carcinogenesis, 16(3):607-612 (1995), herein incorporated by reference. GSTs are anticarcinogenic compounds which inhibit mutagenesis and/or carcinogenesis in laboratory models. Therefore, it is desirable to administer α- Angelicalactone in conjunction with the PONl inhibitors of the present invention to increase the level of anticarcinogens in mice. Extending this treatment to humans is within the level of skill in the art.

EXAMPLE 6 Alkyl Substituted γ-Butyrolactone and PON 1 Inhibitors γ-Butyrolactone (GBL) and its corresponding hydroxy acid, γ-hydroxybutyrate (GHB) produce nonconvulsive seizures in experimental animals that may be used as models for petit mal absences in humans. Anticonvulsant treatment is demonstrated by administering alkyl substituted γ-butyrolactones (e.g., α-ethyl-α-methyl-γ- butyrolactone (α-EMGBL) and α,α-dimethyl-γ-butyrolactone (α-DMGBL). Klunk et al, Science, 217:1040-42 (1992), incorporated herein by reference. Studies have shown that the hydroxy acid has no effect, and that the lactone is the active form for preventing seizures. Therefore, it is desirable to administer α-DMGBL or α-EMGBL in conjunction with the composition of the present invention to increase the amount of active α-DMGBL or α-EMGBL in the systemic circulation. Accordingly, the ED₅₀ of α-EMGBL for the prevention of pentylenetetrazole induced clonic seizures in mice is about 1.8 mmole kg. The ED₅₀ of α-DMGBL for the prevention of pentylenetetrazole induced clonic seizures in mice is about 2.4-4.1 mmole kg. It is found that the ED₅₀ is reduced for mice when either α-DMGBL and α-EMGBL are co-administered with the PON 1 inhibitors of the present invention. When either α-DMGBL and α-EMGBL are co-administered to humans with the PON 1 inhibitors of the present invention, the effective dose for preventing seizures (e.g., petit mal absences) is found to be about 0.001-1000 mg per day, preferably about 0.01-50.0 mg per day.

Claims

1. A composition comprising i) a drug containing a lactone structure, and ii) an inhibitor of paraoxonase.

2. The composition of Claim 1, wherein said drug and inhibitor are in an aqueous mixture.

3. The composition of Claim 1, wherein said drug and inhibitor are in a tablet.

4. The composition of Claim 1, wherein said drug containing a lactone structure is selected from the group consisting of lovastatin, simvastatin and mevastatin.

5. The composition of Claim 4, wherein said inhibitor is N-bromo-epsilon- caprolactam.

6. The composition of Claim 1, wherein said drug containing a lactone structure is selected from the group consisting of angelicalactone, γ-butyrolactone, decanolactone, thiobutyrolactone, spironolactone.

7. The composition of Claim 1, wherein said inhibitor is a lactam.

8. The composition of Claim 1, wherein said inhibitor is selected from the group consisting of isatin, ε-caprolactam and 2-hydroxyquinoline

9. The composition of Claim 1, wherein said inhibitor comprises oxindole.

10. A method, comprising: a) providing i) a drug recipient, ii) a drug containing a lactone structure, and iii) an inhibitor of paraoxonase; and b) administering said drug and said inhibitor to said drug recipient.

11. The method of Claim 10, wherein said drug recipient is a human.

12. The method of Claim 10, wherein said drug and inhibitor are in an aqueous mixture.

13. The method of Claim 10, wherein said drug and inhibitor are in a tablet.

14. The method of Claim 10, wherein said drug containing a lactone structure is selected from the group consisting of lovastatin, simvastatin and mevastatin.

15. The method of Claim 14, wherein said inhibitor is N-bromo-epsilon- caprolactam.

16. The method of Claim 10, wherein said drug containing a lactone structure is selected from the group consisting of angelicalactone, γ-butyrolactone, decanolactone, thiobutyrolactone, spironolactone.

17. The method of Claim 10, wherein said inhibitor is a lactam.

18. The method of Claim 10, wherein said inhibitor is selected from the group consisting of isatin, ε-caprolactam and 2-hydroxyquinoline

19. The method of Claim 10, wherein said inhibitor comprises oxindole.

20. The method of Claim 10, wherein said drug and said inhibitor are administered essentially simultaneously.