Home Cosmetic Science Talk Formulating 50SPF W/O Mineral Sunscreen Formula Improvement- All opinions are welcomed!

  • 50SPF W/O Mineral Sunscreen Formula Improvement- All opinions are welcomed!

    Posted by majibo on March 31, 2024 at 5:26 am

    Dear Community of Formulators,

    I would greatly appreciate your comments on the formula I’ve been working on. The first sample was created three months ago and was tested at 45°C for several days, appearing to be satisfactory. My objective was to develop a sunscreen with low viscosity and suitable for cold processing. However, given the significant load of Zinc Oxide, I didn’t feel confident relying solely on the single emulsifier (Olivem 2090). Therefore, I decided to add Peg-8-Hydrogenated Castor Oil to provide some body. This addition resulted in increased viscosity, but I am not dismayed, as stability is paramount to me. (I aim for a shelf life of three months after opening and two years overall.)

    The only issue I am encountering is that the formula has a very dry finish. While people seem to like it, I personally desire a slightly greasier texture. I believe improving spreadability could address this. While it’s not terrible, I am seeking a better result. Do you have any suggestions for enhancing after-feel and spreadability? Additionally, I welcome any recommendations regarding emollient and emulsifier combinations. Your feedback on the entire formula would be immensely appreciated.

    Thank you in advance for your insights.

    Here is my formula:

    Aqua q.s

    Magnesium Sulphate(MgSO<sub style=”background-color: var(-bb-content-background-color); font-family: inherit; color: var(-bb-body-text-color);”>4</sub>. 7H<sub style=”background-color: var(-bb-content-background-color); font-family: inherit; color: var(-bb-body-text-color);”>2</sub>O) %1

    Olivem 2090 (Polyglyceryl-4 Olivate/Polyricinoleate) %4

    Caprylic Capric Triglyceride %15

    Avocado Oil %15

    Micno DCC (ZnO dispersed in CCT, Zinc Oxide 62.0-65.0 %, Caprylic/Capric Triglyceride 31.5-35.5 %,

    Polyhydroxystearic Acid 2.5-3.5 %) %38

    Peg-8-Hydrogenetad Castor Oil %1

    Zinc Stearate %1

    Tocopherol %0,5

    Phenoxyethanol, Ethylhexylglycerin %1

    Neroli EO %0,8

    attached 2 vieos of 3 months old sample, it has been under the sunlight for 3 hours on my desk, measured 42C degrees.

    ketchito replied 2 weeks, 4 days ago 3 Members · 10 Replies
  • 10 Replies
  • Fekher

    Member
    April 1, 2024 at 11:40 am

    Your formulation didn’t reach the 100%, then it lacks just water?

    • majibo

      Member
      April 1, 2024 at 11:56 am

      Hi fekher, thanks for your attention and your reply! The rest is Aqua as you’ve guessed. “q.s: quantum satis”, means “as much as needed” or “sufficient amount”. In this case it is %23,7 🙂

      • Fekher

        Member
        April 1, 2024 at 12:01 pm

        With which language q. s? I’am always searching about q.s 😊

        Then for spreadability and other needs I guess dimethicone will gives you all.

        • majibo

          Member
          April 1, 2024 at 12:25 pm

          In Latin 🙂

          Dimethicone would be a good choice, but the customer i work for is looking for more natural ingredients. I have no problem with synthetic ingredients, as you can see there are some in my formula, but you know some customers hear some ingredients and don’t like them in their product 😀 Do you have other more “natural” recommendations? 🙂

          • Fekher

            Member
            April 1, 2024 at 12:32 pm

            I find convincing costumer that it is the best choice better then following costumer in bad choice unless don’t convince him and don’t say that it contains silicone just when he try it he will like the texture (professional formulator should make the best choice follow the costumers you will make the worst hhh)

            Then may you will try C12-15 alkyl benzoate or peg7 glyceryl cocoate but dimethicone almost too better.

            • majibo

              Member
              April 1, 2024 at 1:01 pm

              Totally agree with you about convincing the customer! You gave me a great idea, i’ll make 2 samples and one will contain Dimethicone, and one without. Let’s see how they react 🙂 Thanks a lot for the advices!

              Any other suggestions on this formula?

            • Fekher

              Member
              April 1, 2024 at 1:13 pm

              I was working with your preservative untill i discovered that it is not fungicide effective, however oxide zinc in sush level will help a lot in preservation so your preservation system is not sure.

              Then may just increasing the level of Peg-8-Hydrogenetad Castor Oil will do the job without any additional ingredient so may you have 3 samples or more to do.

            • majibo

              Member
              April 3, 2024 at 12:45 pm

              (Sorry for my late reply) Good point indeed! I sent a sample without any preservative and asked the laboratory to conduct a challenge test. Surprisingly, the sample passed the test. I attribute this success to the low water activity and the high load of zinc oxide in the formula. Therefore, I’m contemplating not using any preservatives. What are your thoughts on this?

              Thanks for the ideas, so I’ll try, C12-15 and cocoate and also increasing the HCO, see if one of them make a big difference. Dimethicone sure will do a big difference but i’ll try that too 😀

            • Fekher

              Member
              April 3, 2024 at 7:09 pm

              If really it is for sure don’t need a preservative this will be good news,however all industrial products use preservative.

  • ketchito

    Member
    April 3, 2024 at 10:57 pm

    Please, add a preservative. I don’t think you’ll get too low in water activity not to need one(s). Many weak preservative systems (that when used in real life fail) pass challenge tests, so be cautious about those results.

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