Shelf - life of natural cosmeceutical product: Accelerated storage and stability test. Nur Zatul Iradah Bt. Roslan UTM INTERNATIONAL CAMPUS 8 OCTOBER 2010
Introduction Natural based formulation Natural cosmetics have become a major trend in recent years The awareness of natural resources based product is increasing. Natural cosmetics serve to beautify and care for the human body by means of ingredients from nature. Natural cosmetics should stimulate and support our natural skin functions, rather than supplanting physiological processes.
Natural preservatives: - Extracts (Grapefruit seed, Rosemary) - Essential oils ( Tea Tree, Neem seed, etc.) - Vitamins (Vitamin E, vitamin C) Loss of preservatives: Loss of viscosity (product becomes thinner) Emulsion break (separation of water and oil) Cloudiness of previously clear products Loss or change of colour Drop on ph (product becomes more acid)
Potassium sorbate as preservative in cosmetic: Usually used as food preservative Safe preservative in cosmetic and personal care product especially at ph 6.5. Good skin compatibility and easy to use, especially in salt form. Common microorganisms inhibited by potassium sorbate: Aspergillus sp. Fusarium sp. Penicilium sp. Yeast
Microbial contamination of cosmetic products is a matter of great importance to the industry The contamination of cosmetic product can result in their being converted into products hazardous for consumers. Microbiologist working in the field of cosmetics are frequently required to design preservative systems that provide good protection.
Accelerated Testing Predict normal shelf life of the product. methods to foresee if these products can fail more quickly than they would under normal use conditions. the need to observe failures of products is to better understand their failure modes and their life characteristics. i
Qualitative analysis: Accelerated storage test Stability test Microbiology test Quantitative analysis: Arrhenius relationship Design of Experiment
Objective To analyse the stability of natural based cream formulation using accelerated storage test and microbial analysis.
Methodology Preparation of base cream formulation using Mixture Design Stability test: 1) Freeze thawing : 4 C 24 hours, 25 C 24 hours, 3 cycles. 2) Centrifugation test : 3000 rpm, 30 minutes. Microbiology analysis: Microbiology analysis: total plate count, total yeast and mould, Staph. aureus, Pseudomonas, Salmonella, Enterobacter and E. coli.
Development of a base natural cream Mixture design was applied to develop a base natural cream formulation (data not shown). Eleven independent variables were chosen to evaluate the combined effects of three responses. The response values were viscosity, stability and ph.
Ingredients in formulation Ingredients Oil phase Virgin coconut oil (VCO) Palm oil Beeswax Glycerin Stearic acid Tween 80 Soy lecithin Water phase Distilled water Xanthan gum Acacia gum Potassium sorbate Essential oils Action Humectants (moisturize) Emollient (Lubricity and soothing) Emollient Emulsifier Emulsifier Emulsifier Emulsifier Dilute and dispersed ingredients Softener Preservative/ anti-microbe agent Preservative/ anti-microbe Anti-microbe agent/fragrance
Response parameter after optimization Response Viscosity it (cpa.s) Stability (%) ph Predicted Observed Predicted Observed Predicted Observed Cream 1 21 564.6 19 359 100 100 6.5 6.499 Cream 2 21 771.6 17 227 100 100 6.5 6.5 Cream 3 21 564.1 23 918 100 100 6.5 6.5 Cream 4 19 489.6 16 209 99.998 100 6.4449 6.498 Targeted parameters: viscosity 16 000 cpa.s 24 000 cpa.s, 100% stability at ph 6.5
Final formulations (100g) Cream VCO Palm Oil Beeswax Glycerin Stearic Tween Soy Distilled Xanthan Acacia Potassium acid 80 lecithin water gum gum sorbate 1 4.61 4 2.93 0.01 0.23 1.87 1.67 77.31 3.42 2.16 1.6 2 4.90 4.04 2.65 2.05 0.01 1.94 2.66 74.03 3.72 2.21 1.6 3 4.58 4.75 3.00 2.03 1.68 1.48 3.86 72.21 3.71 0.91 1.6 4 3.98 3.65 2.75 2.12 0.45 0.99 2.91 76.57 3.61 1.16 1.6 Liposome = 1%(coated with antioxidant), nanocarrier Antioxidant = Sodium ascorbate Essential oils: 0.2% 200µl (Lavender, grapefruit,ylang ylang, tea tree) Stability test = Freeze - thawed (3 cycles )
Accelerated testing of cream formulation tability % of s 100 90 80 70 60 50 40 30 20 10 0 1 month 2 months 4 months 6 months 12 months Storage time Freeze - thawed Centifugation Stored at room temperature Centrifuge at 3000 rpm, 30 minutes Constant ph, 6.5
Microbiological Analysis Analysis was done using standard method from British Pharmacopeia Year 2008. 10g of four final base cream formulation was analysed on total plate count, total yeast and mould, Staph. Aureus, Pseudomonas, Salmonella, Enterobacter and E. coli. Analysis was done for 9 months (so far) and excellent result was observed.
Microbiology Analysis Results Parameter Duration Unit = Cfu/ g Cream 1 Cream 2 Cream 3 Cream 4 Coated Uncoated Coated Uncoated Coated Uncoated Coated Uncoated Total Plate Count 2 months 1.0 10³ 2.5 10³ 0 2.5 10³ 2.5 10³ 8 10³ 9 10¹ 2.5 10³ 4 months 4 10¹ 1 10³ 1.2 10² 5.0 10¹ 2.0 10¹ 8 10¹ 3.5 10¹ 3.0 10¹ 9 months ND ND ND ND ND ND ND ND Total Yeast and Mould 2 months 2.2 10² 2.5 10³ ND 1.0 10¹ ND 2 10¹ ND 6 10¹ 4 months 6.5 10³ 3.5 10¹ 8.0 10¹ 6.0 10¹ ND 1.5 10¹ ND ND 9 months ND ND ND ND ND ND ND ND
Concluding remarks Mixture design can be a tool to formulate stable cosmetic. Accelerated testing and normal storage condition has shown that the formulation obtained from Mixture Design was stable for at least 12 months. Our natural a preservative esystem has been shown to protect from microbial contamination for at least 9 nine months so far