Novel Process in Preparation of Deproteinized Natural Rubber Latex

Abstract:

Natural rubber latex (NRL) tapped from Hevea brasiliensis is composed of cis-1,4-polyisoprene as the major polymer which provides several desirable physical properties which make it to be interesting in pharmaceutical formulations. However, the International Union of Immunological Societies (IUIS) has reported about latex allergies caused by 14 NRL proteins (Hev b1-14). This problem can be coped with deproteinization of NRL in order to obtain deproteinized natural rubber latex (DNRL). This study aimed to prepare DNRL by novel process which was easy to perform and used pharmaceutical acceptable agents. The obtained DNRL was assayed for remained protein amount in form of nitrogen content by Kjeldahl method. Its physical properties were characterized. Its stability was also physically investigated. The DNRL was tested for the skin irritation in 3 rabbits. It was found that the protein amount of DNRL was 0.257% while the initial protein amount of fresh NRL was 1.531%. Hence, the protein was removed for 83.21%. DNRL had the average pH of 7.27. Both protein content and pH value implied that DNRL should be safe for skin application. DNRL possessed Newtonian flow with low viscosity which should be easy for mixing with other components in the further pharmaceutical formulations. The particle size, polydispersity index (PI), and zeta potential of DNRL were 441.0 nm, 0.240, and -42.53 mV, respectively, indicating narrow size distribution and physical stability. The dry rubber content and total solid content of DNRL were controlled as 39.55% and 40.72%, respectively. The suitable storage condition of DNRL was at 2-8°C in tight containers where DNRL could be kept for longer than 4 months. Very slightly irritation with no allergy caused by DNRL was observed in the tested rabbits. It could be concluded that this deproteinization process was easy and the prepared DNRL by this process was suitable and safe for using in further pharmaceutical and cosmetic formulations.

References

[1] A. D. Roberts, Natural Rubber Chemistry and Technology, Oxford University Press: Oxford, (1998).

[2] WHO/IUIS Allergen Standardization Committee Allergen Nomenclature; Available online: http: /www. allergen. org/search. php?allergensource=latex (March 4, 2013).

[3] ASTM International. Standard Test Method for Rubber-Nitrogen Content D3533, ASTM: West Conshohocken, (2001).

[4] ASTM International. Standard Specification for Rubber-Concentrated, Ammonia Preserved, Creams, and Centrifuged Natural Latex D1076, ASTM: West Conshohocken, (2001).

DOI: 10.1520/d1076

[5] Organization for Economic Co-operation and Development (OECD), OECD Guidelines for Testing of Chemicals, Section 4: Health Effects, Test No. 404: Acute Dermal Irritation/Corrosion, Paris Cedex, (2002).

DOI: 10.1787/9789264242678-en

[6] A. Martin, Physical Pharmacy, Lea & Febiger: Philadelphia, (1993).