by way of illustrating and providing a more complete appreciation of the present invention and many of the attendant advantages thereof , the following detailed description and examples are given concerning the novel methods and formulations . the present invention employs nicotinic acid or a compound other than nicotinic acid itself which the body metabolizes into nicotinic acid , thus producing the same effect as described herein . the other compounds specifically include , but are not limited to the following : nicotinyl alcohol tartrate , d - glucitol hexanicotinate , aluminum nicotinate , niceritrol and d , 1 - alpha - tocopheryl nicotinate . each such compound will be collectively referred to hereinbelow by “ nicotinic acid .” as stated hereinabove , nicotinic acid has been employed in the past for the treatment of hyperlipidemia , which condition is characterized by the presence of excess fats such as cholesterol and triglycerides , in the blood stream . according to the present invention , a sustained release composition of nicotinic acid is prepared as an example . by “ sustained release ” it is understood to mean a composition which when orally administered to a patient to be treated , the active ingredient will be released for absorption into the blood stream over a period of time . for example , it is preferred that in a dosage of about 1500 milligrams ( hereinafter “ mgs ”) of nicotinic acid , approximately 100 percent of the nicotinic acid will be released to the blood stream in about 4 to about 24 hours . the specific sustained release composition according to the present invention employs an effective antihyperlipidemic amount of nicotinic acid . by “ effective antihyperlipidemic amount ” it is understood to mean an amount which when orally administered to a patient to be treated , will have a beneficial effect upon the physiology of the patient , to include at least some lowering of total cholesterol , ldl cholesterol , triglycerides and lp ( a ) and at least some increase in hdl cholesterol in the patient &# 39 ; s blood stream . an exemplary effective antihyperlipidemic amount of nicotinic acid would be from about 250 mgs to about 3000 mgs of nicotinic acid to be administered according to the invention as will be more fully described hereinbelow . this amount will vary dependent upon a number of variables , including the psychological needs of the patient to be treated . preferably , there is also included in the sustained release composition according to the present invention , a swelling agent which is compounded with the nicotinic acid , such that when the composition is orally administered to the patient , the swelling agent will swell over time in the patient &# 39 ; s gastrointestinal tract and release the active nicotinic acid , or a compound which produces nicotinic acid into the gastrointestinal system for absorption into the blood stream , over a period of time . as is known in the art , such swelling agents and amounts thereof , may be preselected in order to control the time release of the active ingredient . such swelling agents include , but are not limited to , polymers such as sodium carboxymethylcellulose and ethylcellulose and waxes such as bees wax and natural materials such as gums and gelatins or mixtures of any of the above . because the amount of the swelling agent will vary depending upon the nature of the agent , the time release needs of the patient and the like , it is preferred to employ amounts of the agent which will accomplish the objects of the invention . an exemplary and preferred swelling agent is hydroxypropyl methylcellulose , in an amount ranging from about 5 % to about 50 % parts by weight per 100 parts by weight of tablet or formulation . the preferred example will ensure a sustained time release over a period of approximately 4 - 24 hours as demonstrated by in vitro dissolution techniques known to the art . a binder may also be employed in the present compositions . while any known binding material is useful in the present invention , it is preferred to employ a material such as one or more of a group of polymers having the repeating unit of 1 - ethenyl - 2 - pyrrolidinone . these polymers generally have molecular weights of between about . 10 , 000 and 700 , 000 . and are also known as “ povidone ”. amounts of the binder material will of course , vary depending upon the nature of the binder and the amount of other ingredients of the composition . an exemplary amount of povidone in the present compositions would be from about 1 % to about 5 % by weight of povidone per 100 parts by weight of the total formulation . processing aids such as lubricants , including stearic acid , may also be employed , as is known in the art . an exemplary amount of stearic acid in the present compositions would be from about 0 . 5 % to about 2 . 0 % by weight per 100 parts by weight of tablet or formulation . examples of various embodiments of the present invention will now be further illustrated with reference to the following examples . in order to demonstrate the effectiveness of the compositions and method of the present invention over known antihyperlipidemia compositions and methods heretofore known in the art , a number of substantially identical composition were prepared according to the disclosure hereinabove . the composition ingredients and amounts are listed in table ia hereinbelow . the ingredients were compounded together to form a tablet . more specifically , niaspan ® once - daily tablets in accordance with the present invention utilize a hydrophilic matrix controlled drug delivery system . this is a dynamic system composed of polymer wetting , polymer hydration and polymer disintegration / dissolution . the mechanism by which drug release is controlled depends on , for example , initial polymer wetting , expansion of the gel layer , tablet erosion and niacin solubility . after initial wetting , the hydrophilic polymer starts to partially hydrate , forming a gel layer . as water permeates into the tablet increasing the thickness of the gel layer , drug diffuses out of the gel layer . as the outer layer of the tablet becomes fully hydrated it erodes . it is believed that this erosion results in additional drug release . the controlled release from this matrix delivery system can be modified depending on the type and molecular weight of hydrophilic polymer used . a niaspan ® formulation consists of niacin , methocel ® e10m premium , povidone k90 and hystrene ® 5016 ( stearic acid ). methocel ® e10m premium is utilized as a controlled - release agent in the niaspan ® formulation . methocel ® is a partly o - methylated and o -( 2 - hydroxypropylated ) cellulose and is available in several grades which vary in terms of viscosity and degree of substitution . methocel ® is manufactured by dow chemical . povidone k90 is employed as a granulating / binding agent in a niaspan ® formulation . povidone is a synthetic polymer consisting of linear 1 - vinyl - 2 - pyrrolidone groups , the degree of polymerization of which results in polymers of various molecular weights , or as indicated above . it is characterized by its viscosity in aqueous solution , relative to that of water , expressed as a k - value , ranging from 10 - 120 . povidone k90 has an approximate molecular weight of 1 , 000 , 000 . povidone is a hygroscopic , water soluble material . povidone k90 present in a niaspan ® formulation is manufactured by isp ( international specialty products ). hystrene ® 5016 is utilized as an external lubricant in the niaspan ® formulation . hystrene ® 5016 is a mixture of stearic acid and palmitic acid . the content of stearic acid is not less than about 40 . 0 % and the sum of the two acids is not less than about 90 . 0 %. hystrene ® 5016 is manufactured by vitco . refer to table ib for niaspan ® formulation details . qualitatively , the four tablet strength formulations are identical . the major component of each formulation is a granulated mixture of niacin , methocel ® e10m and povidone k90 . the granulation process improves compression properties . niaspan ® formulations are presented in white caplet shape tablets . caplet dimensions differ with respect to product strength . the 375 mg and 500 mg niaspan ® tablets are compressed with tooling measuring approximately 0 . 687 ″ in length × 0 . 281 ″ by width . the length and width of the 750 mg and 1000 mg tooling measures approximately 0 . 750 ″× 0 . 320 ″. target tablet weight and hardness dictate thickness across the four niaspan ® products . the production of the niaspan ® tablets will now be described generally as set forth below . niaspan ® granulation raw materials are dispensed and granulated in a high shear granulator . the wet granules are sieved into a fluid bed drier and are dried . when the drying process is complete , the granules are milled . milling ensures uniform particle size distribution throughout the niaspan ® granulation . a niaspan ® tablet blend is manufactured by blending the niaspan ® granulation , extragranular methocel ® e10m and hystrene ® 5016 . the quantities of each niaspan ® tablet blend component will depend on the particular niaspan ® dose being manufactured ( refer to table ib ). a niaspan ® tablet blend is compressed to form niaspan ® tablets . niaspan ® tablet physical properties will vary depending on the particular niaspan ® dose being manufactured . production of niaspan ® tablets will now be discussed in greater detail . the initial stage of manufacturing is the same for all four tablet strengths of niaspan ® ( 375 , 500 , 750 , and 1000 mg ). one batch of niaspan ® granulation is comprised of four individual 40 . 0 kg units of granulation which are processed separately , but under like conditions . the four individual granulations are sampled and tested individually and subsequently released for blending . the base granulation is not strength specific and may be used to manufacture any tablet strength of niaspan ®. the ingredients in the base granulation are set forth in table ic below : * purified water , usp is used as a granulation reagent and does not appear in the finished granulation . raw materials are quantatively dispensed into appropriately labeled double polyethylene - lined containers using calibrated scales . purified water , usp is dispensed into an appropriate vessel from which it is later pumped during the wet - massing operation . a littleford fm130 granulator is charged with approximately one half of the niacin , usp required for the process unit (˜ 17 . 4 kg ) followed by about 4 . 00 kg of methocel ®, usp e10m premium cr grade ; about 1 . 20 kg of povidone , usp ; and the balance of the niacin , sp (˜ 17 . 40 kg ). the powder bed is dry mixed in the littleford fm130 granulator , with choppers on , for approximately 1 minute . at the completion of the 1 - minute pre - mix cycle , about 12 . 0 ± 0 . 05 kg of purified water , usp are sprayed onto the powder bed at a rate of about 2 . 40 ± 0 . 24 kg / minute . immediately following the addition of the purified water , usp , the unit is granulated for about 5 minutes . the granulated unit is discharged into double polyethylene - lined containers and then manually loaded into a glatt bowl while being passed through a # 4 mesh screen . the glatt bowl is loaded into a glatt tfo - 60 fluid - bed drier with an inlet air temperature setting of about 70 ° c .± 5 ° c . the unit is dried until a moisture level of ≦ 1 . 0 % is obtained as determined using a computract ® moisture analyzer , model ma5a . the dried granulation is discharged into appropriately labeled , double polyethylene - lined drums and reconciled . the dried and reconciled granulation is passed through a kemutec betagrind ® mill equipped with a 1 . 5 mm screen and running at approximately 1500 rpm . the milled granulation is collected into appropriately labeled , double polyethylene - lined drums and reconciled . the milled granulation is sampled and tested by quality control and released prior to further processing . the released granulation units are charged to a patterson - kelley 20 ft 3 v - blender after which they are blended together for about 10 ± 1 minutes and then discharged to appropriately labeled , double polyethylene - lined containers . as stated above , niaspan ® tablets are formulated from a common granulation which is blended with appropriate quantities of methocel ®, usp e10m premium cr grade and stearic acid , nf to achieve the final dosage formulation . tables ia and ib describe the formulation for each niaspan ® tablet strength , 375 mg , 500 mg , 750 mg , and 1000 mg , respectively . two study groups consisting of eleven and fourteen patients each were formed . blood samples were taken from the patients , and tested for total cholesterol ldl cholesterol triglycerides and hdl cholesterol to establish baseline levels from which fluctuations in these lipids could be compared . the patients were then placed upon a regimen of the above discussed tablets , totaling approximately 1500 mg of nicotinic acid , once per day before going to bed . after eight weeks of this regimen , the patients were again tested for lipid profiles . the results of the tests conducted at eight weeks , showing the changes in the lipid profiles as a percentage change from the baseline , are reported in the table hereinbelow . positive numbers reflect percentage increases and negative numbers reflect percentage decreases in this table . the data reported in table ii shows that the ldl levels in the group a patients had a mean decrease of − 13 . 9 % and triglyceride decrease of − 18 . 9 % hdl cholesterol levels , the beneficial cholesterol , were raised by 23 . 0 % in this group . similar results were obtained with the group b patients . these studies demonstrate that dosing the sustained release formulation during the evening hours or at night provides reductions in ldl cholesterol levels equal to immediate release niacin on a milligram per milligram basis , but superior reductions in triglyceride reductions when compared to sustained release formulations dosed during daytime hours on a milligram per milligram basis . additionally , the increases in hdl cholesterol obtained from dosing the sustained release formulation during the evening or at night were + 23 . 0 % for one group and + 25 . 3 % for the other group . dosing during the evening therefore provides reduction in ldl cholesterol plus significant decreases in triglycerides and increases in hdl cholesterol with once - a - day dosing . groups a and b were also tested for liver enzymes ( ast , alt and alkaline phosphatase ), uric acid and fasting glucose levels at the start of the study described hereinabove ( to form a baseline ) and at two , four and eight week intervals . the results of these tests are listed in tables iii - vii hereinbelow . a dosed twice - per - day as described in “ a comparison of the efficacy and toxic effects of sustained - vs immediate release niacin in hypercholesterolemic patients ” by mckenney et al . journal of the american medical association . mar . 2 , 1994 ; 271 , no . 9 , pages 672 - 677 . in order to provide a comparison between the state of the art prior to the present invention , and in order to quantify the magnitude of the improvement that the invention provides over the prior art , another study was conducted . this study included 240 patients dosed according to the present invention as described hereinabove . compared to this group was the group of patients studied by mckenney et al ., as reported hereinabove . the results of this study are reported in table viii hereinbelow . the results of the comparison of the studies reported in table viii show that the control group ( the mckenney group ) had 18 of 23 , or 78 percent of the patients therein drop out of the test because of an increase in their respective liver function tests . the patients withdrew at the direction of the investigator . in comparison , a group of 240 patients treated according to the present invention had zero patients drop out , based upon the same criteria for withdrawal . the tests results reported above indicate that this sustained release dosage form caused no elevation in liver function tests ( i . e ., no liver damage ), no elevations in uric acid and only a small , 7 . 5 % increase in fasting glucose levels which in fact decreased during continued therapy . thus it should be evident that the compositions and method of the present invention are highly effective in controlling hyperlipidemia in hyperlipidemics , by reducing the levels of ldl cholesterol , triglyceride and lp ( a ) while increasing hdl cholesterol levels . the present invention is also demonstrated not to cause elevations in liver function tests , uric acid or glucose levels for the hyperlipidemics . based upon the foregoing disclosure , it should now be apparent that the use of the compositions and methods described herein will carry out the objects set forth hereinabove . it is , therefore , to be understood that any variations in sustained release formulation evident fall within the scope of the claimed invention and thus , the selection of specific component elements can be determined without departing from the spirit of the invention herein disclosed and described . in particular , sustained release excipients , binders and processing aids according to the present invention are not necessarily limited to those exemplified hereinabove . thus , the scope of the invention shall include all modifications and variations that my fall within the scope of the attached claims .