(7) C. J. Swartz, L. Lachman, T. Urbanyi, and J. Cooper, J.
`Pharm. Sci., 50,145(1961).
`(8) L. Lachman, T. Urbanyi, S. Weinstein, J. Cooper, and C. J.
`Swartz, ibid., 51,321(1962).
`(9) C. J. Swartz, L. Lachman, T. Urbanyi, S. Weinstein, and J.
`Cooper, ibid., 51.326(1962).
`(10) M. E. Everhard and F. W. Goodhart, ibid., 52,281(1963).
`(11) M. E. Everhard, F. W. Goodhart, and D. A. Dickciu;, ibid.,
`53,338(1964).
`(12) F. W . Goodhart, H. A. Lieberman, D. S. Mody, and F. C.
`Ninger, ibid., 56,63(1967).
`(13) P. Turi, D. Brusco, H. V. Maulding, R. A. Tausendfreund,
`and A. F. Michaelis, ibid., 61,1811(1972).
`(14) N. A. Armstrong and G. A. March, ibid., 63.126(1974).
`(15) B. R. Hajratwala, ibid., 63,129(1974).
`(16) A. M. Raff, ibid., 52,291(1963).
`(17) M. E. Everhard, D. A. Dickcius, and F. W. Goadhart, ibid.,
`53,173(1964).
`(18) A. M. Raff, ibid., 53,380(1964).
`(19) W. D. Wright, “The Measurement of Colour,” 4th ed., Van
`Nostrand Reinhold, New York, N.Y., 1969, pp. 112,127-134.
`(20) The Committee on Colorimetry, “The Science of Color,”
`
`The Optical Society of America, Washington, D.C., 1963, pp. 83-
`98.
`(21) W. D. Wright, “The Measurement of Colour,” 4th ed., Van
`Nostrand Reinhold, New York, N.Y., 1969, pp. 162-172.
`(22) R. S. Hunter, J. Opt. SOC. Amer., 38,661(1948).
`(23) “ Industrial Color Technology,” R. M. Johnston and M.
`Saltzman, Eds., American Chemical Society, Washington, D.C.,
`1972, pp. 160,161.
`(24) W. D. Wright, “The Measurement of Colour,” 4th ed., Van
`Nostrand Reinhold, New York, N.Y., 1969, p. 315.
`(25) A. C. Hardy, “Handbook of Colorimetry,” Technology
`Press, Cambridge, Mass., 1936, pp. 11,12,59,60.
`
`ACKNOWLEDGMENTS AND ADDRESSES
`
`Received July 15, 1974, from the Quality Control Department,
`Hoffmann-La Roche Inc., Nutley, NJO7110
`Accepted for publication September 26,1974.
`The author thanks Dr. John Donahue and Dr. Margaret Emery
`for their helpful discussions and suggestions and Ms. Barbara
`Lawn for the preparation of the diagrams.
`
`Intragranular Starch: Comparison of
`Starch USP and Modified Cornstarch
`
`JOSEPH B. SCHWARTZX, ELLWOOD T. MARTIN, and EUGENE J. DEHNER
`
`Incorporation of starch USP or a modified cornstarch
`Abstract
`within the granules of several drug formulations was investigated.
`In general, the formulation containing the modified starch exhib-
`ited improved processing characteristics as well as improved tablet
`properties. A comparison of a granulated and a direct compression
`formulation of the same ingredients indicated that granulation of
`an active ingredient is not necessarily detrimental to its (pharma-
`ceutical) availability.
`Keyphrases 0 Starch-comparison
`of starch USP and modified
`cornstarch Excipients-comparison of starch USP and modified
`cornstarch 0 Disintegrants-comparison of starch USP and modi-
`fied cornstarch Binding agents-comparison of starch USP and
`modified cornstarch
`
`Direct compression of pharmaceutical tablets has
`become an integral part of pharmacy in recent years,
`and several components have been designed and
`marketed especially for use in such systems. For ex-
`ample, Manudhane et al. (1) discussed the use of a
`modified cornstarch’ in direct compression formulas.
`Starch USP is a common excipient in solid dosage
`forms, both as a binder and as a disintegrant (2).
`When cornstarch, in either of these two forms, is
`added to a formulation in the dry state (prior to the
`lubricating step), its use is that of a disintegrant.
`When it is incorporated into the granule, either as a
`paste or dry (prior to granulation with some other
`agent), both the binding property and the disinte-
`
`’ Sta Rx 1500 starch, A. E. Staley Manufacturing Co., Decatur, Ill.
`
`328 1 Journal of Pharmaceutical Sciences
`
`grant property may be operative. It is this dual prop-
`erty that is of interest in this study.
`This work documents a comparison of starch USP
`and a modified cornstarch incorporated in the gran-
`ules of several drug formulations. Their processing
`properties and their relative pharmaceutical availabi-
`lities, as indicated by dissolution measurements, were
`studied.
`
`EXPERIMENTAL
`Materials-Excipients
`used in preparing the tablets included
`starch USP, a modified cornstarch’, microcrystalline cellulose*,
`spray-dried lactose3, and magnesium stearate USP. Active ingredi-
`ents included acetaminophen4, ascorbic acid5, chlorothiazide5, le-
`vodopa6, methyldopa5, and probenecid5.
`Tablet Preparation-The
`active ingredients selected were all
`at a dosage of 500 mg, and tablet composition was identical for all
`drugs. The excipients were maintained constant in the experimen-
`tal plan, although the formulation may not have been ideal for any
`one of the drugs. Batch sizes remained constant at 1000 tablets.
`Granulations of 500 g of each active ingredient and 60 g of either
`starch USP or the modified cornstarch with a 7.0% starch paste
`(65O) were processed in a planetary mixer7. In all cases, the starch
`paste was prepared with starch USP. The wet granulations were
`manually screened through a No. 6 screen and oven dried over-
`night at 45”. After dry milling8, the granulations were blendeds
`
`Avicel PH 101, FMC Corp., American Viscose Division, Newark, Del
`Foremost-McKesson, Inc., San Francisco, Calif.
`S. B. Penick & Co., New York, N.Y.
`Merck & Co.. Rahwav, N.J.
`Monsanto Co., St. Louis, Mo.
`Kitchen Aid model K-45, Hobart Manufacturing Co., Troy, Ohio.
`Homoloid, 0.13-cm (0.050-in.) screen.
`Patterson Kelley V-blender.
`
`Par Pharm., Inc.
`Exhibit 1029
`Page 001
`
`

`

`Table I-Granulation
`
`Properties
`
`E,
`B,
`D,
`A,
`F ,
`C,
`Chlorothiazide
`Acetaminophen Ascorbic Acid
`Probenecid
`Levodopa
`Methyldopa
`Drug
`Starch Modified U S P Modified USP Modified USP Modified USP Modified USP Modified USP
`
`10.2
`
`10.0
`
`0 . 8
`
`1 . 0
`
`1 . 4
`
`1 . 7
`
`1 . 0
`
`1 . 4
`
`1 . 0
`
`1 . 4
`
`0 . 6
`
`1 . 4
`
`1 6 . 2
`1 . 6
`5 . 5
`1 1 . 8
`3 7 . 2
`24.7
`36.2
`37.2
`2 6 . 0
`4 0 . 3
`35.6
`2 0 . 1
`13.5
`32.8
`22.6
`1 6 . 4
`0 . 1
`1 0 . 3
`5 . 2
`0 . 6
`4 . 2 - - 1 . 8
`380
`430
`300
`480
`
`4 . 8
`2 3 . 3
`35.5
`2 9 . 5
`6 . 4
`0 . 5
`290
`
`2 . 6
`5 . 6
`4 . 2
`1 0 . 4
`23.7
`23.9
`2 8 . 4
`8 1 . 3
`35.5
`23.5
`2 . 7
`3 0 . 3
`5 . 2 - 1 9 . 2
`0 . 8 - 2 . 7
`290
`340
`250
`
`3 . 8
`8 . 8
`1 7 . 1
`2 7 . 7
`3 0 . 2
`1 2 . 5
`135
`
`2 . 2
`1 5 . 9
`5 7 . 3
`21.5
`2 . 9
`0 . 1
`320
`
`1 . 1
`1 0 . 7
`1 4 . 2
`5 9 . 5
`1 3 . 7
`0 . 8
`170
`
`~ Loss on
`drying, %
`Sieve analysis,
`% on
`screen _._. .~~
`No. 30
`1 2 . 0
`No. 50
`32.8
`No. 100
`2 2 . 8
`No. 200
`1 5 . 7
`No. 325
`1 3 . 7
`3 . 0
`Base
`Meangranule 385
`diameter,
`P mp
`Density, g/ml
`Bulk
`Tapped
`C om pres-
`sibility, %
`Angle of
`repose
`Flow, sec
`Flow
`properties
`on rotary
`press
`
`0.578
`0.770
`24.94
`
`0.633
`0.879
`27.99
`
`0.459
`0.695
`33.46
`
`0.733
`0.449
`0.736 0.991
`38.99
`37.92
`
`0.695
`1.007
`30.98
`
`0.569
`0.769
`26.01
`
`0.466
`0.790
`41.01
`
`0.594
`0.614
`0.787 0.848
`21.98
`29.95
`
`0.343
`0.528
`35.04
`
`0.325
`0.551
`41.02
`
`49'38'
`4
`Good
`
`53'55'
`14
`Fair.
`
`55'25'
`14
`Good
`
`55'25'
`17
`Poor
`
`48'55'
`5
`Good
`
`51'27'
`51O27' 52"18' 58'44'
`8
`16
`7
`49
`Good Good No run Good
`
`53'08'
`26
`Poor
`
`58'44'
`56'49'
`68
`59
`No run No run
`
`Obtained from graphs of the sieve analysis data.
`
`with 130 g of microcrystalline cellulose and lubricated with 0.6%
`magnesium stearate.
`Tablets were compressed on a rotary machinelo operating at 20
`rpm and equipped with only two sets of capsule-shaped punches,
`0.71 X 1.82 cm (%z X 2%2 in.), stationed on opposite sides of the die
`table.
`analyses were performed on sam-
`Testing Procedures-Sieve
`ples of the milled granulations, using a nest of sieves and an elec-
`tromagnetic sieving machine". The compressibility factor was cal-
`culated using:
`
`percent compressibility =
`
`P - L
`x 100
`P
`where P is packed density, and L is loose density. Densities were
`measured using a graduated cylinder and a motorized tapping de-
`vicel2 set to operate for 2000 cycles. Loss-on-drying moisture de-
`terminations were obtained with a moisture balance13.
`The angle of repose was measured for each lubricated mixture
`using the method of Nelson (31, where the repose angle 6 is defined
`by:
`
`(Eq. 1)
`
`h
`C#J = tan-'-
`
`(Eq. 2)
`
`in which h is the height and r is the radius14 of the base of the
`cone formed by the powder. Flow time was determined by the flow
`of 60 g of material through a stainless steel funnel with a 1.5-cm
`opening.
`The tablet properties measured included 20 individual weights
`determined on a semimicro analytical balance15, 20 individual
`thickness measurements made on a dial comparator'6, and break-
`ing strength measurements determined on a motorized tester17.
`The disintegration time of six tablets was measured by the method
`described in USP XVIII.
`
`'OStokes model BB2, modified by removal of the front ejection cam so
`only one compressing station was used.
`Ceoscience Instrument Corp., Mt. Vernon, N.Y.
`l2 Model JEL-STS, Numec Instrument & Control Corp., Monroeville, Pa.
`Is Central Scientific Co., Chicago, Ill.
`l4 The value of r in this set of experiments was 2.55 cm.
`l5 Model H20T. Mettler Instrument Corp., Princeton, N.J.
`l6 Model 282M, B. C. Ames Co., Waltham, Mass.
`l 7 Heberlein hardness tester, Cherry Burrell. Park Ridge, Ill.
`
`Dissolution measurements were carried out by the method spec-
`ified in USP XVIII with a 50-rpm rate of rotation. The dissolution
`medium was 0.1 N HCl unless noted otherwise.
`
`RESULTS AND DISCUSSION
`The various drugs were all treated in the same manner, and
`comparisons were made between the two formulations of each ac-
`tive ingredient, i.e., one containing starch USP and one containing
`the modified starch, and not between active ingredients.
`The physical properties of the granulations (Table I) showed
`some differences. In most cases, the formulation containing the
`modified starch appeared to yield a granulation with a slightly
`larger mean diameter, indicating more efficient granulation. Corre-
`spondingly, the granulations containing starch USP were generally
`more dense. There was very little difference in the moisture levels
`between the two granulations of a given drug.
`The three factors of compressibility, angle of repose, and time of
`flow, which should give some indication of flow properties, general-
`ly predict that the granulations containing the modified starch will
`perform better. The lower the compressibility (4) and the lower
`the response angle (3), the better is the predicted flow.
`This was shown to be true in every case where the material
`flowed sufficiently to produce tablets. With probenecid (Table I),
`neither granulation would flow well enough to compress a tablet on
`the rotary machine, even when operated manually. With ascorbic
`acid, the two formulations seemed to perform equally well. In the
`other four cases, the formulation containing the modified starch
`performed better on the rotary machine than its counterpart con-
`taining starch.
`Although this evaluation is subjective in the case of methyldopa,
`it is less so with the others. Two of the formulations containing
`starch USP (Table I. B and E) required that the machine be
`turned slowly by hand to obtain tablets that did not cap at the
`take-off bar. The starch USP counterpart of a third (Table I, D)
`would not flow sufficiently to run at all.
`The three formulations that would not flow sufficiently to fill
`the die cavity yielded repose angles >56O whereas all others were
`below 56". Time of flow through a funnel also appeared to give cor-
`relation with nonflowability, since the same three formulations
`gave values of 49 sec or greater.
`The physical properties of the resulting tablets (Table 11) sup-
`port this evaluation. The weight control, as indicated by the rela-
`
`Vol. 64, No. 2, February 1975 329
`
`Par Pharm., Inc.
`Exhibit 1029
`Page 002
`
`

`

`I
`
`l
`
`l
`
`
`
`I
`
`1
`
`
`
`I
`
`l
`
`l
`
`
`
`rl
`
`e aa m w
`t- w w
`.
`
`.
`.
`P&o m * w
`r l W
`m
`
`
`w
`
`e o w
`m
`r] m ??
`dr( 0 0 0 maac.1
`m r
`l
`
`t-
`w
`w
`
`
`00 m w
`t-
`rl ??
`?
`0 0 0 m o r l p s m
`+ m
`P-
`00
`w
`m
`
`
`A
`
`h l m
`? Y rid:
`00
`t-0 m o m
`w
`r l r l w
`- m
`
`r ( 7 - i
`rl
`t
`
`M A
`3 :
`
`s g
`
`330 /Journal ofPharmaceutica1 Sciences
`
`Table 111-Tablet Hardness at Equivalent Pressures
`
`Hardness at Equivalent
`Pressures, kg
`Tablet with
`Modified
`Starch
`
`Tablet with
`Starch USP
`
`7 . 5
`5 . 0
`5 . 0
`11 .o
`5 . 0
`9 . 5
`
`10.5
`6 . 5
`6 . 5
`15.5
`8.0
`13.0
`
`Drug
`
`Methyldopa
`Acetaminophen
`Ascorbic acid
`C hlorothiazide
`Levoaopa
`Pro benecid
`
`tive standard deviation, was always higher for the granulation con-
`taining starch USP than for its modified starch counterpart. The
`other physical properties were adequate in all cases, with the ex-
`ception of the hardness of the starch USP formulation of acetami-
`nophen which could not be increased.
`The ability to lessen the tendency for capping and splitting of
`the tablet, as mentioned previously, represents a significant ad-
`vantage of the modified starch. This material apparently acts as a
`stronger internal binder than starch USP; but if too much binding
`power is contributed, disintegration and dissolution could be ad-
`versely affected. What is required is an internal binder that also
`has disintegrant propertiesls.
`The disintegration values (Table 11) are all satisfactory, indicat-
`ing that the additional binding capacity of the modified cornstarch
`is not detrimental. Moreover, the dissolution profiles show a dif-
`ference between the two granulations when a comparison was
`available. As shown in Fig. 1, the release profile of the modified
`starch formula is consistently higher than that of the correspond-
`ing starch USP formula for the five drugs that did yield tablets.
`These comparisons were made on tablets of approximately the
`same hardness values for a given drug. In general, the hardness
`value for the tablet containing starch USP was the maximum pos-
`sible; i.e., no additional compression pressure could be applied. For
`the drugs in Figs. la and Ib, harder tablets were made from the
`modified starch formulation (13 kg for methyldopa and 6 kg for
`acetaminophen); the release profiles, although lower with in-
`creased pressure, were still higher than those for the corresponding
`starch USP tablets. In one case (chlorothiazide), the tablet con-
`taining starch USP was prepared manually with a hydraulic
`presslg to obtain a dissolution comparison.
`To illustrate the differences in internal binding power at equiva-
`lent pressures, tablets were compressed from each mixture on the
`manual hydraulic press. The image in this case was a round, flat
`beveled edge tablet, 1.27 cm (0.5 in.) in diameter. Since the com-
`pressional force remained constant at 2000 lb, the comparisons in
`Table 111 show that the formulation containing the modified
`starch for any drug yielded a harder tablet than did the formula-
`tion containing starch USP.
`As noted, each drug selected for the study was treated in the
`same manner with regard to formulation, granulation, etc. For the
`one soluble drug in the group, ascorbic acid, the mixture was over-
`wet during granulation as expected. For this reason, the experi-
`ment was repeated with a 37% decrease in the quantity of the
`water used for the starch paste.
`Although both formulations performed adequately on the rotary
`tablet press, the one containing the modified starch appeared su-
`perior again. However, no significant difference was observed in
`the two dissolution profiles (Fig. 2). The formulation containing
`the modified starch showed no difference from the previous exper-
`iment (Fig. l c ) , and that containing starch USP improved to an
`equivalent level. This finding appears to indicate that the modified
`starch formulation is relatively insensitive to this change in pro-
`cessing but that the formulation containing starch USP can be ad-
`versely affected by overgranulation.
`Direct Compression-The
`ingredients selected for the experi-
`
`‘8According to the manufacturer’s literature, Sta Rx 1500 starch differs
`from starch USP only from water solubility and particle-size standpoints. It
`contains a 20% maximum cold water-soluble fraction.
`lgCarver laboratory press, Fred S. Carver, Inc., Summit, N.J.
`
`Par Pharm., Inc.
`Exhibit 1029
`Page 003
`
`

`

`100
`
`80
`
`=- 60
`E?
`0
`I-
`3
`0 % 40
`- n
`
`20
`
`0
`
`I I
`
`80
`loo
`
`100
`
`80
`
`E?
`0 2 60
`I- 3
`8
`40 n
`
`20
`
`100
`
`80
`
`60
`
`E?
`2
`3
`I- 3 40
`-
`0
`
`20
`
`I
`10
`5
`MINUTES
`( a )
`
`1
`15
`
`
`
`0
`
`1
`
`10
`5
`MINUTES
`( b )
`
`7
`
`15
`
`
`
`0
`
`5
`
`10
`MINUTES
`
`( C )
`
`15
`
`100
`
`80
`
`E? =- 60
`2
`I-
`3
`0
`-
`40
`n
`
`20
`
`Figure 1-Dissolution profiles of
`(a) methyldopa, (b) acetamino-
`phen, (c) ascorbic acid, (d) chloro-
`thiazide (dissolution medium p H
`8.0 postussium phosphate buffer),
`and (e) leuodopa. Key: 0, starch
`USP; 0, modified starch; and
`--- , increased
`tablet hardness
`(see text).
`
`0
`
`10
`5
`MINUTES
`(d)
`
`15
`
`0
`
`10
`5
`MINUTES
`(e)
`
`15
`
`mental formulation in this work, as mentioned previously, are
`marketed mainly as direct compression excipients. It has been pro-
`posed that a direct compression formulation is preferable for sev-
`eral reasons, one being that the drug is not bound by granulation
`and, therefore, its availability should be superior. This formulation
`was suitable for such an evaluation since the same ingredients
`could be used both ways. In addition, the percentage of the drug in
`the formulation was so high that the primary drawback of direct
`compression formulations, possible lack of content uniformity, was
`not a concern.
`One soluble and one insoluble drug (ascorbic acid and chlo-
`rothiazide, respectively) were selected, and the identical formula-
`tions were prepared as in the previous section but this time by the
`appropriate simple mixing techniques in a twin-shell blenderg.
`With respect to processing, these direct compression mixtures
`were inferior in all cases. None would flow well enough on the rota-
`ry tablet machine to fill the die even when the machine was oper-
`ated manually. This result was not completely unexpected when so
`great a percentage of the formulation was the active ingredient
`which then controlled the physical properties. The experiment was
`continued, however, by compressing manually on the hydraulic
`press.
`The dissolution profiles on the resulting tablets (Fig. 3) were not
`those expected. Although the formulation containing the modified
`
`starch for each drug did exhibit a faster release than the starch
`USP counterpart, each direct compression mixture gave a slower
`release than its granulated counterpart (Figs. l c and Id). The
`values for tablet hardness were held constant for the two experi-
`ments. Thus, it is not always true that the granulation of an active
`ingredient is detrimental to its availability.
`Soluble Excipient-The
`effect of including a soluble compo-
`nent in the formulation under study was of interest. For this rea-
`son, the two chlorothiazide granulations were prepared as before
`but were then mixed with a directly compressible lactose rather
`than the microcrystalline cellulose.
`Again, the processing characteristics of the formulation contain-
`ing the modified starch were superior to the starch USP counter-
`part. While tablets of 15-16 kg in hardness were prepared from the
`former, the latter produced only tablets of 4-6 kg on the rotary
`tablet press.
`For dissolution testing, tablets of equivalent hardnesses were
`prepared by hydraulic press as before. In the case of these lactose
`formulations (Fig. 4), the one containing starch USP gave a higher
`release rate than did its modified starch counterpart. The release
`of the starch USP-lactose formulation was essentially equivalent
`to that of the starch USP-microcrystalline cellulose formulation,
`and both were slower than the modified starch-microcrystalline
`cellulose formulation (Fig. Id ).
`
`Vol. 64, No. 2, February 19751331
`
`Par Pharm., Inc.
`Exhibit 1029
`Page 004
`
`

`

`100
`
`80
`
`’ 60 i
`2
`3 +
`0 8 40
`
`n
`
`20
`
`0
`
`5
`
`10
`MINUTES
`
`1
`15
`
`profile for ascorbic acid tablets. K e y : *,
`Figure 2-Release
`starch USP; and 0, modified starch (see text).
`
`A possible explanation for the release of the modified starch-
`lactose formulation being lower than its microcrystalline cellulose
`counterpart may be that the wicking action of the microcrystalline
`cellulose allows the dissolution medium to act on the granules
`quickly, thus bringing into play the properties of the modified
`starch; in the other formulation, the activity of the solvent is divid-
`ed between the dissolution of the lactose and the action on the
`granules. Thus, in the case of a specialized ingredient such as mod-
`
`0
`
`5
`
`10
`
`15
`
`MINUTES
`Figure 3-Release profiles for direct compression formula-
`tions. K e y : e, starch USP; 0, modified starch; -; ascorbic
`acid; and ---, chlorothiazide.
`
`332 /Journal of Pharmaceutical Sciences
`
`0
`
`5
`
`10
`
`15
`
`MINUTES
`Figure 4-Dissolution profiles for chlorothiazide formulations
`containing lactose. Key: e, starch USP; and 0, modified
`starch.
`
`ified starch, it is important to consider the effect of each ingredi-
`ent in the formulation on the specialized property one is trying to
`utilize.
`
`SUMMARY
`
`Formulations of several drugs were prepared by incorporating
`either starch USP or a modified starch within the granule and sub-
`sequently adding microcrystalline cellulose. In general, for a given
`drug, the formulation containing the modified starch performed
`better during processing (flow and weight uniformity) and exhib-
`ited a slightly faster release rate (under the conditions of the test)
`than did its starch USP counterpart. The modified starch mixture
`produced a harder tablet than the starch USP mixture when com-
`pressional force was held constant. The data also indicate that the
`mixture containing modified starch may be less sensitive to
`changes in processing, i e . , overgranulating.
`When granulated and direct compression mixtures of the same
`ingredients were prepared, the granulated mixtures performed
`better with respect to both processing and dissolution testing. Sub-
`stitution of a soluble component, lactose, for the microcrystalline
`cellulose did not significantly change the properties of the starch
`USP formulation but did lower the release rate of the modified
`starch formulation.
`The results of this study show that although modified starch is
`marketed as a direct compression excipient, it may also be used in
`the granulation technique with possible improvement in process-
`ing properties and pharmaceutical availability as measured by dis-
`solution.
`
`REFERENCES
`(1) K. S. Manudhane, A. M. Contractor, H. Y. Kim, and R. S.
`Shangraw, J. Pharm. Sci., 58,616( 1969).
`(2) “Remington’s Pharmaceutical Sciences,” 14th ed., Mack
`Publishing Co., Easton, Pa., 1970, pp. 1374,1651.
`(3) E. Nelson, J. Amer. Pharm. Ass., Sci. Ed., 44.435(1955).
`(4) R. L. Cam, Jr., Chem. Eng. New York, 72,163 (Jan. 1965).
`
`ACKNOWLEDGMENTS AND ADDRESSES
`Received May 5, 1974, from Pharmaceutical Research and De-
`velopment, Merck Sharp & Dohme Research Laboratories, West
`Point, PA 19486
`Accepted for publication September 19, 1974.
`The authors acknowledge Ms. Alice Thomas for performing the
`dissolution experiments and Mr. E. W. Leach for his technical as-
`sistance.
`To whom inquiries should be directed.
`
`Par Pharm., Inc.
`Exhibit 1029
`Page 005
`
`