mnps other than dissolvable mnps, needles can also be made out of metal or ceramic that will not dissolve in the body environment. these coated drug needles can deliver consistent concentration of drugs without the needles dissolving in the body. this kind of mnps has better performance, but compared to the soluble mnps, metal or ceramic mnps are the older version of mnps. even if the patches are small, the metal or ceramic mnps may cause several waste issues. recycling the metal and ceramic are very hard, as the quantity is very small to overcome the cost to recycle. that is why researchers try to develop the dissolvable mnps with similar characteristic and performance of drug delivery in non-soluble mnps. hollow mnps among all of the mnps, hollow needles allow a bigger amount of delivery up to 200μl. the mechanism mimics the operation of a hypodermic, but the fabrication is hard and complex. the hollow needles introduce a potential failure if the insertion is improper. that is why, among the others, hollow mnps are the least popular because of the complex manufacturing and applying process. advantages disposing needlestick might cause injuries and transmission of pathogen. the mnps may puncture the skin surface, enabling rapid onset of drug bypassing directly into the dermal capillaries. pain-free. can be localized to provide direct access to the intended tissues. less dependent on skilled medical workers, as mnps can be administered safely by the patient itself. some drugs have poor solubility in water, with mnps insoluble drugs and compounds can be directly "injected" to the dermal layer. further enhancing the transdermal delivery of insoluble drugs. better safety compared to needle and syringe method (needlestick). less waste, eliminate pathogen transmission, and injuries. at least 300,000 needlestick related injuries occurred in the us annually, with disposal contribute to almost half of the injuries. mnps as vaccine delivery platform a set of conventional vaccine apparatus needed to be transported. mnps vaccination might be an alternative from direct injection. able to deliver bigger molecules than transdermal patch, mnps can also deliver bioactive molecules with different physical sizes. meaning that inactive virus or pathogen can be introduced in the body without discomfort or skin irritation from conventional injection. possibly it can also reduce the cost of storage that usually needs to be transported in a particular temperature and condition. stated in cdc.gov website, mark prausnitz, co-developer of the microneedle, says "a major advantage of the microneedle patch would be the ease of delivery." the mnps are small and thin compared to bottles of vial, making it possible to transport in massive quantities in a single trip. medical waste such as syringes and dirty needles are also eliminated, reducing the possibility of pathogen transmission of blood-borne disease in rural areas. in a study, measles coated mnps might be resistant to higher temperature compared to vial transport. higher temperature resistance is a safe bet in low income countries, where there is no such luxury for refrigeration. furthermore, the delivery of the vaccine is controlled by the mnps. less requiring highly trained medical workers in developing countries to apply the vaccine. however, the study in mnps measles vaccine is still under development, but opening possibilities in the future for other types of vaccines mnps to reduce obesity obesity is one of the most popular topics in developed countries nowadays. researchers have tried to reduce obesity rate using certain drugs, one in particular known as browning compound. in order to target a certain group of fat tissue, mnps is utilized and shows that the patch can deliver browning nano particles to a certain group of fat tissue. by doing so, the drug's side effects can be reduced as mnps are localized. the result shows that in mice experiments in a four weeks period, the white fat of the mice shrunk. furthermore, an improved metabolism in the mice also signifies that the experiment to reduce obesity using mnps might be worth testing in the future. if the research has been proved successful, mnps treatment might be a great choice, as direct injection obesity drugs need medical professional assistance. while here, mnps can be done by the patient without special skills. mnps for cosmetic and skin care skin treatment including face whitening agent and dark eye circles serum can also incorporated in mnps. its localized property enhance skin whitening delivery to the face area. even a very specific spot like dark eye circles. by measuring the melanin (dark or black pigment found on the skin) index, subjects that are treated with whitening agents coated in mnps show lower melanin index, compared to the whitening essence (topical) group. the treatment lasts for eight weeks, and the result shows mnps might be a promising cosmetic vector because mnps does not introduce skin irritation and can be engineered to localize or specific parts of the body. safety micro needle patch (mnps) might be another choice of safety compared to direct injection using candlestick. not only safety in handling, mnps also promote better disposal and prevent pathogen transmission. under extraordinary circumstances, mnps may cause complication mentioned below. skin irritation under rare circumstances, mnps may cause skin irritation on people with sensitive skin. majority of studies show that mnps do not irritate the skin, but does not close the possibility for sensitive skin group of people. improper application especially for hollow mnps, the not so stiff needles may cause unnecessary puncture to the skin outer layer. thus may cause trauma to the skin and restricting the performance and flow of the drugs to the body. future development because most of mnps applications are still under development, it is important to note the long effect of the efficiency of the drug deliveries. furthermore, more research is needed to get information of what molecule can be delivered using mnps. disposal is also an important topic, as the small plastic backing may contribute to water pollution remembering the compact size can be easily carried away by wind and water without proper disposal. regulatory aspects a transdermal patch is classified by the u.s. food and drug administration as a combination product, consisting of a medical device combined with a drug or biological product that the device is designed to deliver. prior to sale in the united states, any transdermal patch product must apply for and receive approval from the food and drug administration, demonstrating safety and efficacy for its intended use.