Natural fiber exoskeletons of insects and arthropods. In shells and exoskeletons, the chitin fibers contribute to their hierarchical structure. In nature, pure chitin (100% acetylation) does not exist. It instead exists as a copolymer with chitin's deacetylated derivative, chitosan. When the acetylized composition of the copolymer is over 50% acetylated it is chitin. This copolymer of chitin and chitosan is a random or block copolymer. Chitosan is a deacetylated derivative of chitin. When the acetylized composition of the copolymer is below 50% it is chitosan. Chitosan is a semicrystalline “polymer of β-(1-4)-2-amino-2-deoxy-D-glucose”. One difference between chitin and chitosan is that chitosan is
Pharmacy school must study six years to become pharmacists. The best school of pharmacy is at Universidad de Chile , in Santiago de Chile. Chilean pharmacists are prepared not only to dispense and be able to work at clinical and communitary pharmacies, but in Pharmaceutical, Food and Cosmetic industry at every level, including drug development (a Degree is needed here), manufacturing, management, marketing, etc., due to the very strong scientific preparation they receive, including engineering and pharmaceutical technology topics. The official title for pharmacists in Chile is Químico Farmacéutico (Pharmaceutical Chemist), and their degree is Licenciado en Ciencias Químicas y farmacéuticas (Bachelor