In cosmetics, HPMC is used as a humectant to keep skin hydrated and supple. It allows the skin to breathe and prevents clogged pores from forming due to sebum production by the sebaceous glands. In the pharmaceutical industry, HPMC can be used as an excipient or diluent for certain drugs that require slow releases such as tablets or capsules. HPMC does not dissolve easily in water but dissolves easily in alcohols like methanol and ethanol which makes it ideal for use in these drugs due to its low toxicity level compared to other chemicals used currently. 

10 reasons to use HPMC in gluten-free preparations:

1. Improved structure and consistency: Emulates the effect of gluten, providing elasticity and structure to the dough.
2. Moisture Retention: Helps keep gluten-free baked goods more moist and less dry.
3. Suitable for vegan and hypoallergenic diets: It is not derived from animal sources and does not contain common allergens such as gluten.
4. Stabilization: Useful for stabilizing emulsions and suspensions, improving the quality of preparations.
5. Gel formation: Take advantage of its ability to gel at high temperatures for different applications.
6. Thickening Properties: Acts as a thickener, improving the texture of food products.
7. Solubility in cold water: Facilitates incorporation into various recipes without the need for heating.
8. Compatibility: Works well with a wide range of food ingredients.
9. Shelf life: It can help extend the shelf-life of baked goods.
10. Flavor neutrality: It does not alter the flavors of the preparations, maintaining the desired taste.

10 reasons why it is advisable not to use HPMC in gluten-free preparations:

1. Cost: HPMC can be more expensive than other additives or ingredients.
2. Perception of over-processing: Some consumers may prefer less processed products or products with fewer additives.
3. Limitations in replicating sensory properties: It may not be able to exactly replicate all the properties of gluten.
4. Variable applicability: Not all gluten-free recipes benefit equally from the addition of HPMC.
5. Limited Availability: It is not always easily available in all markets or stores.
6. Experimentation needed: May require trial and error to get the proportions right.
7. Additive Dependence: Can lead to increased dependence on food additives.
8. Possible digestive reactions: Although rare, some people may have sensitivities to HPMC.
9. Effects on texture: It can influence the texture of some preparations in an undesirable way.
10. Negative consumer perceptions: Some consumers may have concerns about the use of food additives.