AYU (An International Quarterly Journal of Research in Ayurveda)

: 2014  |  Volume : 35  |  Issue : 1  |  Page : 63--70

Process standardization and characterization of Rajata Sindura

Rohit A Gokarn1, Supriya R Gokarn2, Shobha G Hiremath3,  
1 Department of Rasa Shastra and Bhaishjya Kalpana, Mahatma Gandhi Ayurved College, Hospital and Research Centre, Wardha, Maharashtra, India
2 Department of Dravyaguna, Mahatma Gandhi Ayurved College, Hospital and Research Centre, Wardha, Maharashtra, India
3 Department of Rasa Shastra and Bhaishjya Kalpana, Government Ayurveda Medical College, Bengaluru, Karnataka, India

Correspondence Address:
Rohit A Gokarn
Department of RS and BK, Mahatma Gandhi Ayurved College, Hospital and Research Centre, Wardha, Maharashtra - 442 001


Background: Rajata Sindura (RS) is a mercurial preparation, known for its properties like Rasayana (rejuvinating), Balya (strengthening), Vrushya (aphrodisiac), Medhya (increasing intellect) and can cure various diseases when used with appropriate adjuvant. It is prepared with Hingulottha Parada (purified mercury), Shuddha Gandhaka (purified sulfur) and Shuddha Rajata (purified silver) in a proportion of 1:1:4. Process standardization and characterization of RS are not reported until date. Aim: Pharmaceutical standardization and characterization of Rajata Sindura. Materials and Methods: Purified mercury and silver were triturated to form amalgam, followed by the addition of purified sulfur to prepare Kajjali and lavigated with Vatankura (leaf buds of Ficus benghalensis Linn.) swarasa (juice). This Kajjali was processed by Kupipakwa method. Results and Conclusion: RS was prepared in 33 h with 20.25% yield. Scanning electron microscope coupled with energy dispersive spectroscopy analysis has shown Mercury 86.21%, sulfur 13.27% as major elements; iron, calcium, potassium, magnesium and silver were other detected minor elements. X-ray diffraction report revealed the chemical nature of RS as HgS compound, having cubic crystal structure.

How to cite this article:
Gokarn RA, Gokarn SR, Hiremath SG. Process standardization and characterization of Rajata Sindura.AYU 2014;35:63-70

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Gokarn RA, Gokarn SR, Hiremath SG. Process standardization and characterization of Rajata Sindura. AYU [serial online] 2014 [cited 2021 Jun 12 ];35:63-70
Available from: https://www.ayujournal.org/text.asp?2014/35/1/63/141940

Full Text


Rasa Shastra, an advanced pharmaceutical science describes the conversion of metals and minerals into therapeutically safe and potent forms. Rashoushdhies are herbo-mineral compound formulations, known for their quick curative attributes with small doses. [1] Kupipakwa Rasayana is one among the important formulations described under the Parada Murchana (inducing disease curing property in a drug) and is considered best in terms of its wide spectrum in therapeutics. [2] Kupipakwa Rasayana, is a unique pharmaceutical preparation where in the drug is prepared in a glass bottle (Kupi) and the processing is done in the furnace with the gradual rise of temperature. [3] Pharmaceutical preparation by Kupipakwa method enhances the property of the drug, to form a stable, safe, efficacious compound, which is evident by various studies on Rasasindura.[4],[5] Metals are also used as an ingredient in various Kupipakwa Rasayanas such as Makaradhwaja, Rajata Sindura (RS), Tamra Sindura, etc., Rajata (silver) a widely used metal in therapeutics in different forms such as Bhasma, Sindura, etc., RS contains silver, mercury and sulfur, having therapeutic potential ranging in diseases such as Madhumeha (diabetes), Jwara (fever), Hridroga (heart diseases) and also possesses Rasayana (rejuvenation) and Vajeekarana (aphrodisiac) properties. [6] Until date, no reported studies are available pertaining to standardization and characterization of RS. Hence an attempt has been made to develop pharmaceutical standardization of RS and to explore the structure and composition through sophisticated instrumental facilities like X-ray Diffraction (XRD), Scanning Electron Microscope coupled with Energy Dispersive Spectroscopy (SEM-EDX) and particle size analyzer.

 Materials and Methods

Raw materials

Rajata Sindura (RS) (99.97% pure) was collected from Asmita silver refinery, Bangalore. Hingula (cinnabar) and Gandhaka (sulfur) were procured from Amrita Kesari, Bangalore, and confirmed for their authenticity based on the classical parameters. [7] Vatankura (leaf buds of Ficus benghalensis Linn.) were collected form botanical garden of the Institute and Nimbu (Citrus limon Linn.) was collected from local market. Equipments like Kupi (glass bottle) coated with seven layers of mud smeared cloth with capacity of 750 ml; Bhatti (traditional furnace) measuring diameter-5 cm: Height-85 cm, upper hole- 30 × 30 cm 2 for wood: Lower hole-20 × 30 cm 2 for collecting ash, Valuka Yantra (iron vessel filled with sand for placing the Kupi) measuring diameter inner-20 cm: Brim-30 cm: Height-30 cm: Depth-27 cm: Thickness-03 cm, Valuka (sand) and wood were prepared as per the requirement.


Preparation of RS involves the following steps:

Purvakarma includes purification of raw materials, preparation of Kajjali and BhavanaPradhana Karma involves processing of drugs in furnacePaschat Karma, breaking of Kupi and collection of product.


Mercury was extracted from cinnabar by Nadayantra method. [8] Initially, cinnabar was levigated with Nimbu Swarasa (juice of C. limon) and fine powder of triturated cinnabar was spread uniformly over a cotton cloth (equal to the weight of cinnabar), tied with thread and ignited. While igniting an earthen pot was placed inverted to facilitate the collection of mercury. Thus obtained mercury was collected carefully and filtered through four folded cloth [Table 1], [Figure 1]. Sulfur was purified by Dhalana method. [9] Impure sulfur was taken in a stainless steel container along with Ghrita (1/4 part) and melted over mild flame. A muslin cloth smeared with Ghrita was tied to the mouth of the container containing milk. As soon as sulfur melted, the mixture was poured through the cloth into the container containing milk. Thus obtained sulfur was washed with hot water and dried. The above process was repeated for two more times [Table 2], [Figure 2]. Samanya Shodhana of Rajata[10] was carried out by quenching in different liquids like Tila Taila (sesum oil), Takra (butter milk), Gomutra (cow's urine), Aranala (sour gruel prepared out of rice), and Kulattha Kwatha (decoction of Vigna unquiculata Linn.) as per the classical reference. Vishesha Shodhana[11] was done by Nirvapa (heating and dipping) in Nimbu Swarasa for 7 times [Table 3], [Figure 3].{Figure 1}{Figure 2}{Figure 3}{Table 1}{Table 2}{Table 3}

Preparation of Kajjali

Purified silver foils were placed in mortar containing purified mercury. Immediately trituration was carried out in mortar by using pressure till silver amalgamated completely [Figure 4]. This was added with fine powder of purified sulfur and trituration was continued until the formation of Kajjali (fine, smooth, lusterless powder). This was added with Vatankura Swarasa [Figure 5] and left over night for soaking in mortar [Figure 6]. [12] The next day trituration was done for 4 h, allowed to dry, collected and stored in a glass container [Table 4].{Figure 4}{Figure 5}{Figure 6}{Table 4}

Pradhana Karma

Kajjali was filled in the Kupi and kept in the Valuka Yantra [Figure 7], which was placed in the Bhatti [Figure 8]. Pyrometer was placed at the bottom of Kupi in Valuka Yantra. Fire was set; temperature reading was carried out at regular intervals of 30 min. Kramagni (gradual rise of temperature) was maintained [Graph 1 [SUPPORTING:1]]. Corking was done after complete cessation of flame [Figure 9] and observing the Siddhi Lakshanas, like complete cessation of sulfur fumes, Suryodaya Lakshana (red appearance of the bottom) [Figure 10] and positive copper coin test, etc., [Table 5].{Figure 7}{Figure 8}{Figure 9}{Figure 10}{Table 5}

Paschat Karma

Kupi was left for self-cooling, layers were scraped and the bottle was broken carefully [Figure 11]. Product deposited at the neck of the Kupi was carefully collected [Figure 12] and weighed. RS was prepared in three batches to develop Standard Manufacturing Process (SMP).{Figure 11}{Figure 12}

Analytical study

Two samples i.e. Rajata Sindura Kajjali (RSK) and RS were analyzed for physicochemical parameters like pH value, [13] ash value, [14] acid insoluble ash, [15] water soluble ash, [16] loss on drying, [17] tests for the presence of total mercury, [18] and total sulfur containt. [19] Instrumental analysis like XRD by Philips X PERT PRO diffractometer Cu-Kα radiation (ϑ =1.5405 A°), (SEM, model JSM-6380 LA from JEOL, Japan), and particle size determination by laser scattering particle size analyzer (LA-910) using triple distilled water as a medium were carried out for characterization of RSK and RS.

 Observations and Results

Different phases of the desired characteristics during the process were observed viz. sulfur fuming, melting and boiling of Kajjali, blue flame, and confirmative test (flame disappearance, Shita Shalaka test, red hot appearance of bottom, copper coin test) were observed and recorded. RS collected from the neck of Kupi from all the three batches was weighed [Table 6]. Results of various organoleptic, physico-chemical parameters, XRD [Graph 2 [SUPPORTING:2]] and [Graph 3 [SUPPORTING:3]], SEM-EDX [Graph 4 [SUPPORTING:4]] and [Graph 5 [SUPPORTING:5]] and particle size were analyzed [Table 7],[Table 8],[Table 9] and [Table 10].{Table 6}{Table 7}{Table 8}{Table 9}{Table 10}


Extraction of mercury from cinnabar yielded 71.2%, even though cinnabar contains 86.13% of mercury, the classical method did not yield the amount of mercury up to expected quantity. The reason of loss may be due to mercurial vapors escaping out during the procedure and some amount of mercury entering the minute pores of earthen pot used for collection. However, previous work carried out on the same concluded 73% of yield from the same method. [20] During purification of sulfur, 3.8% of loss was observed. It is evident from the observation that bright yellow color and sulfurous odor was reduced after each Dhalana. During Rajata Shodhana, minimal weight loss was observed. Although silver gets tarnished by the contact of various liquid media, less corrosion was seen on silver, which is evident by the intact silver foils after process. It took 30 h to make amalgam and 120 h to make Kajjali. In Kupipakwa Rasayana, the heating pattern plays an important role to obtain a quality product. As per classical texts, Krama Vruddha Agni[21] is adopted during the process. The heating duration was divided into three equal parts i.e., 11 h each. This heating pattern was divided in to 3 stages Mridu (120-250°C), Madhayma (250-450°C) and Tivragni (450-650°) [Graph 1]. The first stage of heating represents the melting of RSK, whereas in second and third stage, boiling of RSK and sublimation of the product towards the neck of the Kupi was evident. Various tests like copper coin test, Sheeta Shalaka test were conducted to confirm the absence of free sulfur. Testing of the product collected at the neck was also done to ensure proper formation of compound. Self-cooling of Kupi was ascertained before procuring product as it has a major role to play in re-crystallization.

Specific procedure adopted in Kupi Paka and temperature pattern followed facilitates the chemical reaction. Change in chemical nature and crystalline structure was evident from XRD reports in RS (vermillion) as compared with RSK (imitrite).

According to previous research works, Rasasindura prepared in Kupi possesses HgS as cinnabar having hexagonal crystal structure [22] whereas RS has shown HgS as cubic crystal system with primitive lattice. Both Rasasindura and RS possess same chemical formula-HgS, but differ in the crystal lattice. Change in the crystal structure can occur due to embedded metal ion in crystal system. [23] Here, silver ions present in the crystal lattice may be responsible to change the crystal structure.

RS revealed HgS compound in XRD study, by comparing with XRF results one can validate the analysis as the percentage of Hg (86.21%) and S (13.27%) are stoichiometrically accurate to that of theoretical calculation in HgS compound. Inclusion of minor and trace elements such as Mg (0.11), P (0.12), K (0.02), Ca (0.07) and Fe (0.1) may be due to the impregnation of Vatankura Swarasa. [24]

The RS particle size was 9.59 μm, which is slightly larger than Kajjali. RS is a condensed and re-crystallized product under high temperature and pressure, so segregation of particle may be responsible for the increase in particle size; however, it also depends on the trituration undertaken while sampling.


Rajata Sindura (RS) can be prepared in 33 h by following intermittent gradual rise of temperature, i.e. 11 h each of Mridu (120-250°C), Madhyama (250-450°C) and Tivragni (450-650°C) with 20.25% yield. RS is a mercurial compound possesses HgS with cubic crystal structure with Hg 86.21%, S 13.27% as major elements and Fe, Ca, K, Mg and Ag as minor elements.


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