Use of Polymers, minimalist ingredients.

DeepTitan

Hi, I don't understand concepts well enough, so appreciate if you can correct my understandings below, appreciate it.

a) I read somewhere that you use for transdermal drug delivery, cationic polymers (i.e. positive charge polymers) as skin and hair are negatively charged, so these polymers bind to the skin, and in that process, the product gets a chance to permeate through the skin barrier.

b) so while the above is merely one component (i.e. binding to skin) of topical delivery science, another would be to force the product to actually enter the skin.  I can see 2 methods: 1. diffusion, 2. transport.  What factors help diffusion and transport?  

c) Diffusion: I can think of pH of product solution as helping with diffusion?.  Transport:  As for transport, maybe mixing an ingredient that has a skin transporter present?  What would be transporter ingredient?

d) so what happens if you combine cationic polymers (such as chitosan, guar gum) with anionic (such as xanthan gum).  You end up with a Polyelectrolyte Complex.  1. Would that be not suitable for Transdermal use?  2. Would the application be for oral delivery instead?

e) Can you comment on this topical formulation with least ingredients but still sufficient to penetrate at least in epidermal, but preferably in dermis as well: 

Active ingredients (safe even if goes into systemic circulation): x (hard to dissolve, lipophilic product), y (hydrophilic product)

Solvents: 1. try to dissolve in healthiest oils first.  2 If fail, Glycerin, 3. If fail Propylene glycol

Polymers: For max skin absorption: what do you think about: Gum arabic vs Guar gum vs Chitosan vs Xanthan gum vs Sodium Hyaluronate.   How would each fare for dermal vs epidermal absorption? 

Short-term stability/preservation: citric acid, edta

f) Is there something lacking in above.  How do you think about adding sunflower lecithin to the above?

Thanks a lot, sorry for this being long. 

DeepTitan

is there way to edit original thread? 
Headline is too cheesy should be:  Use of Polymers, minimalist ingredients.
e1: should have read: try to dissolve in healthiest oil (for lipophilic) and water (for hydrophilic) components. 
e3: If fail, Propylene Glycol or Alcohol (e.g. Everclear 190)

Pharma

DeepTitan said:

Hi, I don't understand concepts well enough (obviously... no offense!), so appreciate if you can correct my understandings below, appreciate it.

a) I read somewhere that you use for transdermal drug delivery, cationic polymers (i.e. positive charge polymers) as skin and hair are negatively charged, so these polymers bind to the skin, and in that process, the product gets a chance to permeate through the skin barrier. Are you sure you don't confuse it with transfection? Polymers on dead matter usually don't work (with some exceptions but applications therewith are highly limited).

b) so while the above is merely one component (i.e. binding to skin Precisely, it binds to skin and then sticks there) of topical delivery science, another would be to force the product to actually enter the skin (that's one of the standard ways to do it, it's called occlusion and works by the principle of solubility/insolubility).  I can see 2 methods: 1. diffusion (that would be the another standard which it the one probably most often referred to in cosmetics when talking about penetration enhancers), 2. transport (in cosmetics, one can rarely use a transport system for an active ingredient mostly because it involves covalent binding and living cells which are only reached after the hard part has been achieved i.e. penetration through epidermis).  What factors help diffusion and transport? Laws of physics and principles of biology

c) Diffusion: I can think of pH of product solution as helping with diffusion? Anything which creates a gradient such as pH may be used for some things under certain circumstances. However, pH is mostly used to tune lipophilicity/hydrophilicity of acidic and alkaline actives.  Transport:  As for transport, maybe mixing an ingredient that has a skin transporter present? (??? You mean like gene technology?)  What would be transporter ingredient? Again, ???

d) so what happens if you combine cationic polymers (such as chitosan, guar gum) with anionic (such as xanthan gum).  You end up with a Polyelectrolyte Complex.  1. Would that be not suitable for Transdermal use? Likely not. What's the point of that most likely precipitated blend anyway? 2. Would the application be for oral delivery instead? Why?

e) Can you comment on this topical formulation with least ingredients but still sufficient to penetrate at least in epidermal, but preferably in dermis as well: 

Active ingredients (safe even if goes into systemic circulation): x (hard to dissolve, lipophilic product), y (hydrophilic product) If you use both, the vehicles for the two will have to be different, unless you use some injection device such as CLICK.

Solvents: 1. try to dissolve in healthiest oils first (Define healthy. Why an oil?).  2 If fail, Glycerin, 3. If fail Propylene glycol If it fails with glycerin, why should it work with propylene glycol?

Polymers: For max skin absorption: what do you think about: Gum arabic (it's used for oral drug delivery of lipophilic actives) vs Guar gum vs Chitosan vs Xanthan gum vs Sodium Hyaluronate.   How would each fare for dermal vs epidermal absorption? Absorption of what? An active or the polymer itself? Low molecular weight hyaluronic acid does penetrate to a degree, against all predictions and principles of skin penetration, though I'm not aware that this would help penetration of other ingredients in any regard. Same goes for a very few other polymers such as heparan. Chitisan, if properly formulated, may work, the others are just polymeric thickeners and gel builders.

Short-term stability/preservation: citric acid, edta That's not preservation, that's chelation. Also, they are partially incompatible with chitosan and do not really contribute to physical stability.

f) Is there something lacking in above. Yes, there is: some books on your shelf and a sound basic knowledge. Again, no offense.  How do you think about adding sunflower lecithin to the above? I think that reading those books first... or maybe just buy active ingredients encapsulated in lecithin based liposomes or the like might be easier.

Thanks a lot, sorry for this being long.

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