Physicochemical characterization of an Iron based Indian traditional medicine: Mandura Bhasma.

Ayurveda is a unique system of medicine which uses metals and minerals in the form of bhasma (fine powder obtained through calcinations). Mandura is one of such mineral having various therapeutic uses. An effort has been made in the present study to characterize raw and processed Mandura using sophisticated analytical tools as a step forward to standardization. Mandura bhasma was prepared following references of Ayurvedic classics. To assure the quality of the prepared bhasma, Rasa Shastra quality control tests like rekhapurnatvam (particles enter into furrows of human hand), varitara (floating of product particles on water), irreversible etc., were used. Bhasma fulfilling these tests was analyzed using X-ray Diffraction (XRD) analysis. This revealed that raw Mandura contained Fe(2)Si0(4), and Mandura bhasma contained Fe(2)O(3) and SiO(2). Scanning Electron Microscopy (SEM) studies showed that the grains in Mandura bhasma were uniformly arranged in agglomerates of sizes 200-300 nm as compared to the raw Mandura, which showed a scattered arrangement of grains of sizes 10-2 microns. It may be concluded that this conversion of raw Mandura, a complex compound, into a mixture of simple compounds having nano-sized particles is due to the particular process of calcination employed.

Introduction

Metallic preparations called bhasma (fine powder obtained through calcinations) are unique to the Ayurvedic system of medicine. Their preparation involves treatment of metals/minerals with specified plant juices followed by calcinations in the presence of air so that the metallic state is transformed into the suitable compound form1. These preparations are in practice since long. However, there is paucity of scientific analytical studies carried out on these products to characterize them and even existing ones are not up to the mark.

Mandura bhasma, an iron based preparation has been used in therapeutics of anemia, jaundice, poor digestion, edema, skin diseases etc2. Generally, Mandura bhasma is prepared in two steps: Purification, by, heating to red hot state and quenching in liquid media like cow's urine or Triphala decoction and calcination, by puta system of heating in gajaputa (specific amount of heat given through fixed quantity of fuel). During calcination, purified Mandura is levitated with Triphala (fruits of Terminalia chebula Retz., Terminalia belerica Roxb. and Emblica officinalis Gaertn.) decoction, aloe vera (Aloe barbadensis Mill) juice etc.

Variations in the raw material used as well as failure in following standard operative procedures (SOP) for bhasma preparation leads to alteration in properties of the finished product. Standardization is a measurement for ensuring the quality and is used to describe all measures, which are taken during the manufacturing process and quality control leading to a reproducible quality. Failure in reproducibility reduces efficacy and raises safety concerns. In view of high demand for the use of bhasma, there is an urgent need to bring about standardization of their preparation process and the end product. Ayurvedic texts have also given due emphasis on quality control of finished products. Different parameters like lusterless, rekhapurnatvam (particles enters into furrows of human hand), varitara (floating of product on water), niruttha (inability to regain metallic form), irreversible, etc., are described to achieve acceptable and standard bhasma. Though pharmaceutical, experimental studies on Mandura bhasma have been done earlier, any work regarding characterization of the same has not been done earlier. This study was performed to characterize the Mandura bhasma using sensitive tools and techniques. Outcomes of this study could be used as standards for evaluating quality and reproducibility of the Mandura bhasma.

Materials and Methods

Preparation of Mandura bhasma:

Processing of the Mandura was done according to the process listed in the “Rasa Tarangini”3 and AFI. Raw materials were obtained from local market. Coarse powdered Mandura was heated in coal furnace up to red-hot stage (630°C temp) and quenched in cow's urine. This purification process was repeated for seven times. This purified Mandura was powdered and triturated with Triphala decoction. Small pellets were made and dried. After drying pellets were placed in between two sharavas (earthen pots) placed one above the other (called Sharava samputa). The pots were subjected to heat in the electric furnace at 650° C in aerobic condition. This process was repeated twenty seven times to get the finally prepared Mandura bhasma. The final product in the form of pellets were taken out of the earthen pot, powdered and packed in airtight containers.

Analysis on Ayurvedic parameters:

Bhasma obtained from above procedure was tested on following Ayurvedic parameters and was found complied with these tests.

Lusterless: The bhasma was taken in a Petri dish and observed for any luster in daylight through magnifying glass lens. No luster was observed in the bhasma.

Rekhapurnatvam: A pinch of Mandura bhasma was taken in between the thumb and index finger and rubbed. It was observed that the bhasma entered into the lines of the finger, and was not easily washed out from the cleavage of the lines.

Varitaratavam: A small amount of the prepared bhasma was sprinkled over the still water taken in a beaker. It was found that the maximum bhasma particles floated over the surface of the water.

Tasteless: The prepared bhasma was found to be tasteless when a small amount was kept on the tongue.

Irrreversible: 20 gm of Mandura bhasma was triturated with equal amount of each seeds of gunja (Abrus precatorius Linn.), clarified butter, honey, borax and guggulu (Commiphora mukul Engl.) (Collectively called Mitra panchaka) and pellets were made. These were subjected to puta on 650°C in EMF maintained for one hour. Next day after self-cooling pellets were triturated and any accumulated mass was not found.

Analysis on modern parameters:

The bhasma as well as the starting material (raw Mandura) both were analyzed using the following qualitative techniques:

X-ray diffraction

Scanning electron microscopy

1. X-ray diffraction study

Powder XRD method is perhaps the best-known sensitive method as a phase characterization tool. It can uniquely differentiate between crystalline phases of different materials and can be used for identifying the different crystal structures of the same chemical compound also. The powdered sample was spread onto a double-side tape with a spatula, which was then placed on an aluminum sample holder. All the peaks were recorded on the chart, and the corresponding 2 theta values were calculated which are presented in Table No 1 and Table 2.

Table No.1

X-Ray Diffraction of raw Mandura

Table No.2

X-Ray Diffraction of Mandura bhasma

X-ray diffraction pattern of the raw Mandura and bhasma are shown in Fig No. 1 and 2 respectively. The strongest peak observed in the raw material was of Fayalite or Iron silicate (Fe2SiO4), this is in accordance with API5. Whereas that observed in the bhasma was of Ferrous oxide of iron (Fe2O3). Peaks of SiO2 were also observed in the bhasma. In the raw material only one phase of Iron silicate (Fe2SiO4) was identified while in Mandura bhasma different phases were identified including Fe2O3 and SiO2. Presence of sharp diffraction peaks shows the highly crystalline nature of the drug.

Fig. No. 1

Showing X-Ray Diffraction of the raw Mandura

Fig. No.2

Showing X-Ray Diffraction of the Mandura bhasma

2. Scanning electron microscopy (SEM) study

SEM study was done to explore very detailed images showing surface morphology of samples. The mounted sample was placed inside the microscope's vacuum column through an airtight door, and then the air was pumped out. After the air was pumped out of the column, a beam of electrons was emitted by an electron gun from the top. This beam travels downward through a series of magnetic lenses designed to focus the electrons to a very fine spot. Near the bottom, a set of scanning coils made the focused beam to move back and forth across the mounted sample, row by row. As the electron beam hits each spot on the sample, secondary electrons are backscattered from its surface. A detector counts these electrons and sends the signals to an amplifier. The final image was built up from the number of electrons emitted from each spot on the sample. [Fig 3, 4 and 5]

Fig. No. 3

Scanning Electron Microscopy feature of raw Mandura

Fig. No. 4

Scanning Electron Microscopy feature of raw Mandura

Fig. No. 5

Scanning Electron Microscopy feature of Mandura bhasma

The study revealed regular and uniform arrangement of cluster of granules in bhasma which was not observed in the raw material. Also study showed the particle size reduction in the final product. Particle size in the raw material was 10-2 mm. Significant reduction in the particle size to 200- 300 nm was observed in the prepared bhasma. Ayurvedic concepts of trituration and levigation are used to reduce particle size.

Discussion

Bhasmas are unique Ayurvedic metal based preparations made by following sophisticated pharmaceutical processes incorporating herbs, converting them into a suitable form. They are used in the Indian subcontinent since the seventh century BC7 and widely recommended for treatment of a variety of chronic ailments. The bhasmas prepared are well tolerated both for short-term and long-term use; moreover rejuvenation effects of these preparations are mentioned in Ayurveda8 which need long term administration. So these should be well tolerated for long time period.

The methods of the bhasma preparation vary so much for each metal. In view of high demand for the use of bhasma, there is an urgent need to bring about standardization of their preparation process as well as the end product. Structural information of these finished products is also an absolute necessity to unravel their mode of action. The quality assurance of such medicines can be achieved only through good manufacturing practice, regulatory control, research and physico-chemical fingerprinting with reference to authentic drug formulations.

In this study, an attempt has been made to bring forth the physicochemical characters of Mandura bhasma as a step forward to standardization. Powder X Ray Diffraction (PXRD) was used to fingerprint a particular crystalline phase or mixture of phases. In fact it is a very important tool in the pharmaceutical industry for checking the presence of polymorphism, solubility and bioavailability in oral drugs. The intense sharp diffraction peaks in both the samples clearly confirmed the presence of high crystallinity. The study also revealed peaks of Fe2SiO4 in the raw material and Fe2O3 and silicon oxide (SiO2) in the final product. Knowing where Mandura is obtained from this is explainable as contamination with soil.

Images (Fig.4 SEM) of both the samples illustrated the regular and uniform arrangement of cluster of granules in bhasma which was not observed in the raw material. Also presence of agglomeration of the particles observed in the bhasma may be due to repeated calcinations during processing. Particle size in the raw material was 10-2 mm. Significant reduction in the particle size to 200- 300 nm was observed in the prepared bhasma.

The size of the particles of a solid substance is of considerable importance, as it affects its dissolution rate and the rate of absorption9. These sizes imply high surface to volume ratio of the particles that translate into better absorptivity and so effective drug delivery10. This particle size reduction in the final product also substantiates Ayurvedic processes of levigation and calcination as a tool of particle size reduction.

Conclusion

The particular method adapted in this study for Mandura bhasma preparation converted Fe2SiO4 of the raw material into a mixture of Fe2O3 and SiO2 in the final product i.e. Mandura bhasma. The techniques employed for purification and calcination of Mandura significantly reduced the particle size in Mandura bhasma. This reduced particle size may facilitate absorption and assimilation of the Mandura bhasma into the body. The above data obtained through physico-chemical evaluation will be assistive in standardization of this iron containing preparation, Mandura Bhasma.