Assay of Calcium gluconate IP Pharmaceutical Analysis I Practical
Pharmaceutical Analysis I Practical: Limit test for (1) Chloride (2) Sulphate (3) Iron (4) Arsenic Preparation and standardisation of (1) Sodium hydroxide (2) Sulphuric acid (3) Sodium thiosulfate (4) Potassium permanganate (5) Ceric ammonium sulphate Assay (1) Ammonium chloride (2) Ferrous sulphate(3) Copper sulphate (4) Calcium gluconate (5) Hydrogen peroxide (6) Sodium benzoate (7) Sodium Chloride Determination of Normality (1) Conductometric titration of strong acid against a strong base (2) Conductometric titration of strong acid and weak acid against a strong base (3) Potentiometric titration
Aim
To determine per cent content of Calcium gluconate in a given sample / To perform the assay of calcium gluconate
Principle
Calcium gluconate can be assayed using complexometric titrations of Ca2+ ions using EDTA as a sequestering (chelating) agent which results in the formation of a relatively stable complex. However, Mordant-Black II which is used as an indicator does not give distinct colour change. Hence, calcium ions are not directly titrated against disodium EDTA. Rather a displacement or replacement type of titration is used or performed wherein, a known volume of 0.05M magnesium sulphate solution is added (5ml) which acts as a displacing agent.
Magnesium ions displace calcium ions from the calcium indicator complex and form a more stable Mg indicator complex. But this complex is less stable than the Mg-EDTA complex. The relative stability of different complexes decreases in the following order: Ca-EDTA > Mg-EDTA > Mg-In > Ca-In. Initially when both calcium and magnesium ions are present in the solution and when the indicator is added it forms a complex with Mg as Mg-In is stronger than Ca-In complex and imparts a pink colour to the solution.
When titration commences added EDTA forms a complex with calcium ions as a Ca-EDTA complex is stronger than the Mg-EDTA complex. when all the calcium ions are complexed then free Mg++ forms complex with EDTA and the endpoint is reached then Mg-In complex breaks liberating free Mg+2 and In- which forms complex with EDTA and free In- imparts a blue colour to the solution. The ammonia solution buffers the solution at a pH 10
Standard
Calcium gluconate (mol. wt.: 448.4) contains not less than 98.5% and not more than 102.0% of C12H22CaO14, H2O.
Procedure
Preparation of 0.1M disodium edetate solution
Dissolve ______ g of disodium edetate in sufficient water to produce 1000ml
Standardization of 0.1M disodium edetate solution
- Weigh accurately about 0.8 g of granulated zinc dissolved by gentle warming in 12 ml of dil. Hydrochloric acid and 0.1ml of bromine water.
- Boil to remove excess bromine, cool and add sufficient water to produce 200ml. pipette 20 ml of the resulting solution into a flask and nearly neutralize with 2M sodium hydroxide.
- Dilute to about 150ml with water add sufficient ammonia buffer pH 10.0 to dissolve the precipitate and add 5ml in excess.
- Add 50mg of mordant black II mixture and titrate with the disodium edetate solution until the solution turns green.
Assay of calcium gluconate
Weigh 0.5 g and dissolve in 50 ml of warm water; cool, add 5.0 ml of 0.05 M magnesium sulphate and 10 ml of strong ammonia solution and titrate with 0.05 M disodium edetate using mordant black II mixture as an indicator. Carry out a blank titration.
Reference
Indian Pharmacopoeia 2014; Vol. II; Pg. No. 1253-1254.
Limit test Chlorides, Sulphate, Iron, Heavy metals * Identification tests for Anions and Cations * Prep. & std Sodium Hydroxide, Potassium Permanganate * Assay Ferrous sulphate, Calcium gluconate, Sodium chloride, Ascorbic acid, Ibuprofen * Determination of Melting point & Boiling point * Preparation Benzoic acid from Benzamide, Picric acid from Phenol * Identification & purity test Aspirin, Caffeine
FAQs on Estimation of Calcium Gluconate
Calcium gluconate is a common medication used to treat conditions related to calcium deficiency. Estimating the concentration of calcium gluconate in a solution is important for accurate dosing and administration. Here are some frequently asked questions about the estimation of calcium gluconate:
Estimating the concentration of calcium gluconate ensures that the correct dosage is administered to patients. Calcium is a vital mineral for various bodily functions, and accurate dosing is crucial to avoid underdosing or overdosing.
Common methods for estimating calcium gluconate concentration include complexometric titration and spectrophotometry. Complexometric titration involves reacting calcium ions with a chelating agent to form a complex, while spectrophotometry measures the absorbance of light by the calcium gluconate solution.
In complexometric titration, a chelating agent like EDTA (ethylenediaminetetraacetic acid) forms stable complexes with calcium ions. A solution containing calcium gluconate is titrated with EDTA until the endpoint is reached, indicated by a colour change. The amount of EDTA used corresponds to the amount of calcium ions present, allowing calculation of the calcium gluconate concentration.
Spectrophotometry measures the absorption of light by a solution at a specific wavelength. Calcium gluconate solutions absorb light at a characteristic wavelength. By comparing the absorbance of a sample solution to a standard curve of known concentrations, the concentration of calcium gluconate can be determined.
Yes, there can be challenges, especially in complex samples or mixtures. Interference from other substances present in the solution might affect the accuracy of the estimation. Proper sample preparation and calibration procedures are essential to overcome these challenges.
To ensure accuracy, it’s important to follow proper laboratory techniques, including accurate pipetting, thorough mixing, and precise measurement of reagents. Regular calibration of instruments and using appropriate standards can also contribute to accurate results.
While calcium gluconate is generally considered safe, it’s important to handle all chemicals and solutions with care. Follow proper safety protocols, wear appropriate personal protective equipment, and work in a well-ventilated area.
Yes, some of the estimation methods used for calcium gluconate can also be applied to other calcium-containing substances. However, the specific conditions and procedures might need to be adjusted based on the compound being analyzed.
Advancements in analytical techniques, such as the use of automated titration systems and sophisticated spectrophotometers, have improved the accuracy and efficiency of calcium gluconate estimation.
Calcium gluconate estimation typically requires specialized laboratory equipment and reagents. It is recommended to perform such estimations in a controlled laboratory environment by trained personnel.
Estimating the concentration of calcium gluconate is a crucial aspect of medication preparation and administration. Accurate estimations ensure that patients receive the appropriate dosage for their medical needs, contributing to effective and safe healthcare practices.
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