Doolan KL. Buffering lidocaine with sodium bicarbonate. Am J Hosp Pharm 1994; 51: 2564–2565.

Erramouspe J. Buffering local anesthetic solutions with sodium bicarbonate: literature review and commentary. Hosp Pharm 1996; 31(10): 1275–1282.

MacKay MW, Fitzgerald KA, Jackson D. The solubility of calcium and phosphate in two specialty amino acid solutions. J Parenter Enteral Nutr 1996; 20: 63–66.

Connolly M, Debenedetti PG, Tung H-H. Freeze crystallization of imipenem. J Pharm Sci 1996; 85(2): 174–177.

Johnson FA, Craig DQM, Mercer AD, Chauhan S. The effects of alginate molecular structure and formulation variables on the physical characteristics of alginate raft systems. Int J Pharm 1997; 159(1): 35–42.

Johnson FA, Craig DQ, Mercer A, Chauhan S. The use of image analysis as a means of monitoring bubble formation in alginate rafts. Int J Pharm 1998; 170(2): 179–185.

Choi BY, Park HJ, Hwang SJ. Preparation of alginate beads for floating drug delivery system: effects of carbon dioxide gas- forming agents. Int J Pharm 2002; 239(1–2): 81–91.

O¨ zdemir N, Ordu S, O¨ zkan Y. Studies of floating dosage forms of

furosemide: in vitro and in vivo evaluations of bilayer tablet formulations. Drug Dev Ind Pharm 2000; 26(8): 857–866.

Wei Z, Yu Z, Bi D. Design and evaluation of a two-layer floating tablet for gastric retention using cisapride as a model drug. Drug Dev Ind Pharm 2001; 27(5): 469–474.

Rostami-Hodjegan A, Shiran MR, Ayesh R, et al. A new rapidly absorbed paracetamol tablet containing sodium bicarbonate. I. A four-way crossover study to compare the concentration-time profile of paracetamol from the new paracetamol/sodium bicar- bonate tablet and a conventional paracetamol tablet in fed and fasted volunteers. Drug Dev Ind Pharm 2002; 28(5): 523–531.

Rostami-Hodjegan A, Shiran MR, Tucker GT, et al. A new rapidly absorbed paracetamol tablet containing sodium bicarbonate. II. Dissolution studies and in vitro/in vivo correlation. Drug Dev Ind Pharm 2002; 28(5): 533–543.

Patel H, Stalcup A, Dansereau R, Sakr A. The effect of excipients on the stability of levothyroxine pentahydrate tablets. Int J Pharm 2003; 264(1–2): 35–43.

Shefter E, Lo A, Ramalingam S. A kinetic study of the solid state transformation of sodium bicarbonate to sodium carbonate. Drug Dev Commun 1974; 1: 29–38.

Kuu WY, Chilamkurti R, Chen C. Effect of humidity and temperature on moisture sorption and stability of sodium bicarbonate powder. Int J Pharm 1998; 166(2): 167–175.

Ljunggren L, Volkova N, Hansson H. Calorimetry a method to be used to characterise pyrolytically decarboxylated bicarbonate and

�assess its stability at elevated humidities. Int J Pharm 2000;

202(1–2): 71–77.

Hadgraft JW, Hewer BD. Molar injection of sodium bicarbonate [letter]. Pharm J 1964; 192: 544.

Hadgraft JW. Unsatisfactory infusions of sodium bicarbonate [letter]. Lancet 1966; i: 603.

Smith G. Unsatisfactory infusions of sodium bicarbonate [letter].

Lancet 1966; i: 658.

Gilbert DL, Trissel LA, Martinez JF. Compatibility of ciprofloxacin lactate with sodium bicarbonate during simulated Y- site admin- istration. Am J Health Syst Pharm 1997; 54: 1193–1195.

Trissel LA. Concentration-dependent precipitation of sodium bicarbonate with ciprofloxacin lactate [letter]. Am J Health Syst Pharm 1996; 53: 84–85.

Korth-Bradley JM, Ludwig S, Callaghan C. Incompatibility of amiodarone hydrochloride and sodium bicarbonate injections [letter]. Am J Health Syst Pharm 1995; 52: 2340.

Baaske DM, DeMay JF, Latona CA, et al. Stability of nicardipine hydrochloride in intravenous solutions. Am J Health Syst Pharm 1996; 53: 1701–1705.

Williams NA, Bornstein M, Johnson K. Stability of levofloxacin in intravenous solutions in polyvinyl chloride bags. Am J Health Syst Pharm 1996; 53: 2309–2313.

Panchmatia K, Jolobe OM. Contra-indications of Solpadol [letter].

Pharm J 1993; 251: 73.

Lewis RJ, ed. Sax’s Dangerous Properties of Industrial Materials, 11th edn. New York: Wiley, 2004: 3233.

General References

Hannula A-M, Marvola M, Aho E. Release of ibuprofen from hard gelatin capsule formulations: effect of sodium bicarbonate as a disintegrant. Acta Pharm Fenn 1989; 98: 131–134.

Sendall FEJ, Staniforth JN, Rees JE, Leatham MJ. Effervescent tablets.

Pharm J 1983; 230: 289–294.

Travers DN, White RC. The mixing of micronized sodium bicarbonate with sucrose crystals. J Pharm Pharmacol 1971; 23: 260S–261S.

Authors

CG Cable.

Date of Revision

23 August 2005.

Sodium Borate

Nonproprietary Names

BP: Borax

JP: Sodium borate PhEur: Borax

USPNF: Sodium borate

Synonyms

Borax decahydrate; boric acid disodium salt; E285; natrii tetraboras; sodium biborate decahydrate; sodium pyroborate decahydrate; sodium tetraborate decahydrate.

Chemical Name and CAS Registry Number

Disodium tetraborate decahydrate [1303-96-4]

Empirical Formula and Molecular Weight

Na2B4O7·10H2O 381.37

Structural Formula

Na2B4O7·10H2O

Functional Category

Alkalizing agent; antimicrobial preservative; buffering agent; disinfectant; emulsifying agent; stabilizing agent.

Applications in Pharmaceutical Formulation or Technology

Sodium borate is used in pharmaceutical applications similarly to boric acid (see Boric Acid). It has been used externally as a mild astringent and as an emulsifying agent in creams.(1) It has also been used in lozenges, mouthwashes, otic preparations (0.3% w/v), and ophthalmic solutions (0.03–1.0% w/v). Sodium borate has additionally been investigated in the prevention of crystal formation in freeze-dried solutions.(2)

Preparations of sodium borate in honey have historically been used as paints for the throat, tongue, and mouth, but such use is now inadvisable because of concerns about toxicity in such applications, see Section 14. Sodium borate is also used in cosmetics such as moisturizers, deodorants, and shampoos.

Description

Sodium borate occurs as white, hard crystals, granules, or crystalline powder. It is odorless and efflorescent.

Pharmacopeial Specifications

See Table I.

�Table I:  Pharmacopeial specifications for sodium borate.

 

Test JP 2001 PhEur 2005 USPNF 23    

Identification + + +    

Characters — + —    

Carbonate and + — +    

bicarbonate

Color of solution

+

+

—    

pH 9.1–9.6 9.0–9.6 —    

Heavy metals 420 ppm 425 ppm 40.002%    

Arsenic 45 ppm 45 ppm —    

Calcium — 4100 ppm —    

Ammonium — 410 ppm —    

Sulfates — 450 ppm —    

Organic volatile — — +    

impurities    

Assay 99.0–103.0% 99.0–103.0% 99.0–105.0%  

Typical Properties

Acidity/alkalinity: pH = 9.0–9.6 (4% w/v aqueous solution)

Density: 1.73 g/cm3

Melting point: 758C when rapidly heated. At 1008C it loses 5H2O; at 1508C it loses 9H2O; and at 3208C it becomes anhydrous. At about 8808C the substance melts into a glassy state: ‘borax beads.’

Solubility: 1 in 1 of glycerin; 1 in 1 of boiling water; 1 in 16 of water; practically insoluble in ethanol (95%), ethanol (99.5%), and diethyl ether.

Stability and Storage Conditions

Sodium borate should be stored in a well-closed container in a cool, dry, place. See also Section 18.

Incompatibilities

Sodium borate is incompatible with acids and with metallic and alkaloidal salts.

Method of Manufacture

Sodium borate can be prepared from minerals such as borosodium calcite, pandermite, or tinkal; these are natural sodium or calcium borates. Treatment of the mineral with sodium carbonate and sodium hydrogencarbonate yields the sodium borate decahydrate. In the USA, brine from salt lakes is also an important source of sodium borate.(3)

Safety

Sodium borate has weak bacteriostatic and astringent proper- ties. Historically, sodium borate has been used as a disinfectant in skin lotions and eye-, nose-, and mouthwashes. However, boric acid is easily absorbed via mucous membranes and damaged skin, and severe toxicity has been observed, especially in babies and children.(4) Consequently, the use of sodium

670 Sodium Borate

borate as a disinfectant is now considered somewhat obsolete and careful use is recommended. The toxic effects of sodium borate include vomiting, diarrhea, erythema, CNS depression, and kidney damage. The lethal oral intake is approximately 20 g in adults and 5 g in children.(5)

LD50 (guinea pig, oral): 5.33 g/kg(5,6) LD50 (mouse, IP): 2.711 g/kg

LD50 (mouse, IV): 1.320 g/kg LD50 (mouse, oral): 2.0 g/kg LD50 (rat, oral): 2.66 g/kg

Handling Precautions

Observe normal precautions appropriate to the circumstances and the quantity of material handled; do not combine with acids.

Regulatory Status

Accepted for use as a food additive in Europe. Included in the FDA Inactive Ingredients Guide (otic preparations; ophthalmic solutions and suspensions). Included in nonparenteral medi- cines licensed in the UK, Italy, France, Germany, and Japan. Included in the Canadian List of Acceptable Non-medicinal Ingredients.

Related Substances

Boric acid; sodium borate anhydrous.

Sodium borate anhydrous

Synonyms: borax glass; disodium tetraborate anhydrous; fused borax; fused sodium borate; sodium pyroborate; sodium tetraborate anhydrous.

Empirical formula: Na2B4O7

Molecular weight: 201.2

CAS number: [1330-43-4]

Boiling point: 15758C (decomposes)

Melting point: 7418C

Solubility: slightly soluble in glycerin, and water; practically insoluble in ethanol (95%).

Specific gravity: 2.367

�Comments: the EINECS number for sodium borate anhydrous is 215-540-4.

Comments

Commercially available sodium borate decahydrate is usually present as monoclinic prismatic crystals that become opaque on the surface in dry air. In addition to the decahydrate, a pentahydrate exists; this is also known as ‘jeweller’s borax.’ The anhydrous substance is also available and is called ‘pyroborax.’

The EINECS number for sodium borate is 271-536-2.

Specific References

Prince LM. Beeswax/borax reaction in cold creams. Cosmet Perfum 1974; 89(May): 47–49.

Izutsu K, Ocheda SO, Aoyagi N, Kojima S. Effects of sodium tetraborate and boric acid on nonisothermal mannitol crystal- lization in frozen solutions and freeze-dried solids. Int J Pharm 2004; 273(1): 85–93.

Lyday PA. Boron. In: Mineral Yearbook, Vol. 1. Washington DC: US Department of the Interior US Geological Survey, 1992: 249.

Gordon AS, Prichard JS, Freedman MH. Seizure disorders and anemia associated with chronic borax intoxication. Can Med Assoc J 1973; 108: 719–721, 724.

Lewis RJ, ed. Sax’s Dangerous Properties of Industrial Materials, 11th edn. New York: Wiley, 2004: 3234.

Smyth HF, Carpenter CP, Weil CS, et al. Range-finding toxicity data: list VII. Am Ind Hyg Assoc J 1969; 30(5): 470–476.

General References

—

Authors

HJ de Jong.

Date of Revision

24 August 2005.

Sodium Chloride

Nonproprietary Names

BP: Sodium chloride JP: Sodium chloride

PhEur: Natrii chloridum USP: Sodium chloride

�Table I: Uses of sodium chloride.

Use Concentration (%)

Capsule diluent 10–80

Controlled flocculation of suspensions 41

Direct compression tablet diluent 10–80

To produce isotonic solutions in intravenous or ophthalmic preparations

�40.9

Synonyms

Alberger; chlorure de sodium; common salt; hopper salt; natural halite; rock salt; saline; salt; sea salt; table salt.

Chemical Name and CAS Registry Number

Sodium chloride [7647-14-5]

Empirical Formula and Molecular Weight

NaCl 58.44

Structural Formula

NaCl

Functional Category

Tablet and capsule diluent; tonicity agent.

Applications in Pharmaceutical Formulation or Technology

Sodium chloride is widely used in a variety of parenteral and nonparenteral pharmaceutical formulations, where the primary use is to produce isotonic solutions.

Sodium chloride has been used as a lubricant and diluent in capsules and direct-compression tablet formulations in the past,(1–5) although this practice is no longer common. Sodium chloride has also been used as a channeling agent(6,7) and as an osmotic agent(8,9) in the cores of controlled-release tablets. It has been used as a porosity modifier in tablet coatings,(10) and to control drug release from microcapsules.(11,12)

The addition of sodium chloride to aqueous spray-coating solutions containing hydroxypropyl cellulose or hypromellose suppresses the agglomeration of crystalline cellulose parti- cles.(13) Sodium chloride can also be used to modify drug release from gels(14) and from emulsions.(15) It can be used to control micelle size,(16–18) and to adjust the viscosity of polymer

dispersions by altering the ionic character of a formula- tion.(19,20)

See Table I.

�Water-soluble tablet lubricant 5–20

SEM: 1

Excipient: Sodium chloride, powder

Manufacturer: Mallinckrodt Speciality Chemicals Co.

Magnification: 600×

 

Description

Sodium chloride occurs as a white crystalline powder or colorless crystals; it has a saline taste. The crystal lattice is a face-centered cubic structure. Solid sodium chloride contains no water of crystallization although, below 08C, salt may crystallize as a dihydrate.

Pharmacopeial Specifications

See Table II.

672 Sodium Chloride

Table II: Pharmacopeial specifications for sodium chloride.

�Typical Properties

Acidity/alkalinity: pH = 6.7–7.3 (saturated aqueous solution)

Angle of repose: 388 for cubic crystals

Boiling point: 14138C

Compressibility: with sodium chloride powder of less than 30 mm particle size, tablets are formed by plastic deforma- tion; above this size, both plastic deformation and fracture occur.(1,3,4) See also Figure 1.

Density:

2.17 g/cm3;

1.20 g/cm3 for saturated aqueous solution.

Density (bulk): 0.93 g/cm3 Density (tapped): 1.09 g/cm3 Dielectric constant: 5.9 at 1 MHz

Freezing point depression: see Table III.

Table III: Freezing point depression values of aqueous sodium chloride.

Aqueous sodium chloride solution (% w/v)

�Freezing point depression (8C)

11.69 6.90

17.53 10.82

23.38 15.14

30.39 21.12

Potassium — 4500 ppm(a)(b)  40.05%(a)(b)

impurities

(a) If for use in peritoneal dialysis, hemodialysis or hemofiltration solutions.

(b) If for parenteral use.

SEM: 2

Excipient: Sodium chloride, granular Manufacturer: Van Waters & Rogers, Inc. Magnification: 120×

 

�Hardness (Mohs): 2–2.5

Hygroscopicity: hygroscopic above 75% relative humidity.

Melting point: 8048C

Osmolarity: a 0.9% w/v aqueous solution is iso-osmotic with serum.

Refractive index: n20 = 1.343 for a 1 M aqueous solution.

Solubility: see Table IV.

Table IV: Solubility of sodium chloride.

Solvent Solubility at 208C unless otherwise stated

Ethanol Slightly soluble

Ethanol (95%) 1 in 250

Glycerin 1 in 10

Water 1 in 2.8

1 in 2.6 at 1008C

Thermal conductivity: 1.15 Wm/K at 273 K

Specific heat capacity: 854 J/kg/K

Vapor pressure:

133.3 Pa at 8658C for solid;

1759.6 Pa at 208C for a saturated aqueous solution (equivalent to 75.3% relative humidity).

Viscosity: a 10% w/v solution has a viscosity of 1.19 mPa s (1.19 cP).

Stability and Storage Conditions

Aqueous sodium chloride solutions are stable but may cause the separation of glass particles from certain types of glass containers. Aqueous solutions may be sterilized by autoclaving or filtration. The solid material is stable and should be stored in a well-closed container, in a cool, dry place.

It has been shown that the compaction characteristics and the mechanical properties of tablets are influenced by the relative humidity of the storage conditions under which sodium chloride was stored.(21,22)

Sodium Chloride 673