Solid State Compatibility Study of Rice Bran Wax with Nifedipine for its Use in Pharmaceutical Products


Avish D. Maru*, Prashant V. Bodhe, Rajendra K. Surawase

Loknete Dr. J. D. Pawar College of Pharmacy, A/P-Manur, Tal- Kalwan, Dist- Nasik (M.S.)

*Corresponding Author E-mail:



Rice bran wax is a natural vegetable wax and is a value added by-product of Rice bran oil refineries. It is hard nontacky wax and contains higher fatty alcohols and esters which make it comparable to Carnauba wax. In the present work, studies are carried out on Rice bran wax for various physico-chemical properties like solubility, melting point, specific gravity, moisture content, saponification value, acid value, ester value, hydroxyl value, unsaponifiable matter, Iodine number etc. Moreover the solid state compatibility studies was carried out by using mixture of Nifedipine and RBW in the 1:1 ratio at 60 c for 15 days and observed for its physical changes i. e. discoloration, liquefaction, gas formation etc and chemical changes i.e. interaction in between Nifedipine and RBW. It was carried out by using Differential Scanning Colorimetry (DSC) and Fourier Transform Infrared Spectroscopy (FT-IR). The result shows that there are no physical and chemical changes; therefore RBW can be used in formulations of Nifedipine.


KEY WORDS: Rice bran Wax, Solid state compatibility study, Nifedipine.



Rice (Oryza sativa, Family Graminae) is one of the most important grains in the world. India is second largest producer of Rice in the world. The outer covering of rice kernel after removing the husk is called Rice bran. It is valuable byproduct of rice milling industry because it contains 12-25 % of oil depending on quality. Rice bran wax is the by-product of Rice bran oil refineries .Lots of work is done on RBW in USA, China and Japan but most of those are patented. Nifedipine as a calcium channel blocker used for the treatment of essential hypertension and angina pectoris. It is a BCS Class II drug with poor solubility. The plasma half life of Nifedipine is 2 hrs. Hence, it is an ideal candidate for the preparation of sustained release formulation1, 2 .



The RBW was obtained as a gift sample from Space lab, Nasik in flakes form. Nifedipine was supplied as a gift sample by Cadila Pharmaceuticals Ltd., Ahmedabad, India.



Characterization of Rice bran Wax: The RBW was characterized for its solubility, melting point, specific gravity, moisture content, saponification value, acid value, ester value, hydroxyl value, unsaponifiable matter, Iodine number etc. Pharmacopoeial standard methods were followed for all these tests2.


Solid state compatibility studies:

The compatibility of Nifedipine with RBW was studied. The 50 mg of physical mixtures (1:1) of the RBW and Nifedipine were weighed and transferred to glass vials. These vials were then kept at 60 c for 15 days.


Physical study:

Rice bran wax alone, Nifedipine alone and mixture of RBW and Nifedipine were observed for physical changes like discoloration, liquefaction and gas formation.

The samples were analyzed by Differential scanning Colorimetry and Fourier Transform Infrared Spectroscopy at 0 day and 15 days5, 7, 8.


Differential scanning Colorimetry (DSC):

The DSC measurements were performed on Perkin Elmer coupled to Pyris-6 Software with a thermal analyzer. Accurately weighed samples were placed and sealed in aluminum pans, before heating under nitrogen flow (20 mL/min) at a scanning rate of 10 C/min from 35 C to 300 C for physical mixture and drug and from 35 C to 210 C for RBW. An empty aluminum pan was used as a reference.


Fourier Transform Infrared Spectroscopy:

FT-IR spectra were obtained by FT-IR spectrophotometer (Perkin Elmer). The sample were mixed uniformly with potassium bromide at 1:5 (sample: KBr) ratio. The KBr discs were prepared by compressing the powders (mixture of sample and KBr) at pressure of 5 tons for 5 min in a hydraulic press. The discs were scanned in the range of 500-4000 cm-1 to obtain FT-IR spectra.



Characterization of RBW: The Rice Bran Wax was characterized for various properties and specification set as per Pharmacopoeial guidelines. On the basis of results obtained (table:1) it can be suggested that the rice bran wax is a suitable substitute for carnauba wax and it can be used as coating agent, as a base in cosmetic preparation and in some extent it can be used as release retardant agent in sustained release dosage form.


Solid state compatibility studies:

Physical study:

The results of physical studies after keeping the mixture at 60 c for 15 days observed that there is not any change in colour. There was not any indication of liquefaction and gas formation did not take place. This suggests that there is not any physical change which means the mixture is physically compatible.


DSC study: The DSC thermograms of various samples are given in Fig: 1 there is no significant change in the appearance, shift, or disappearance of endo-thermal peaks. The thermal profile of the mixture remained almost unchanged showing peaks of Nifedipine as well as RBW indicating compatibility of the drug with the examined excipients.


FT-IR study: FT-IR spectra of the sample are given in Fig:2 A FT-IR study shows that all characteristics peaks of drug and Excipients are present, showing no signs of interaction indicating compatibility of the drug with all the examined excipients.


Table.1: Observed values of RBW

Sr. No.


Observed values of

Rice Bran Wax





Insoluble in water

Soluble in ether, ethanol and isopropyl alcohol


Melting point

80.5 c


Specific gravity



Moisture content

0.074 % w/w


Saponification value



Acid value



Ester value



Hydroxyl value



Unsaponifiable matter

40 % w/w


Iodine value



Fig.1 DSC thermograms of A: Nifedipine, B: Rice bran wax, C: physical mixture of Nifedipine: Rice bran wax


Fig.2FT-IR spectra of A: Nifedipine, B: Rice bran wax, C: physical mixture of Nifedipine: Rice bran wax (1:1)



The solid state compatibility studied (DSC and FT-IR) have suggested that Nifedipine is compatible with RBW. This study indicated potential of RBW in the preparation of sustained release formulations of poorly water soluble drug like Nifedipine.



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3. Raymond C Rowe, Paul J. Sheskey, Paul J Wellen, Handbook of pharmaceutical excipients, fourth edition, Pages: 679.

4. Bodmier R, Hermann J. Encyclopedia of Pharmaceutical Technology. Vol. 16 In; Swarbrick J,Boylan JC, editors. Waxes. New York: Marcel Deckker, Inc.; 1997.p. 335-61.

5. G. Banker and C.T. Rhodes, Modern Pharmaceutics, Marcel Dekker, Inc., 2000.

6. MD Idea Exporting Division uses and application rice bran wax, from octacosanol to phytosterol. products/proper/059.html accessed August 2011.

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8. Kanig, JL, Lachman L. Lieberman HA. The theory and practice of Industrial Pharmacy (3ed.). Philadelphia: lea and Febiger; 1986; ISBN 0-8121: p. 977-5.




Received on 13.04.2012 Accepted on 15.05.2012

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Asian J. Pharm. Res. 2(2): April-June 2012; Page 83-85