Case Study Of Caffeine
• Caffeine (anhydrous), BASF, Germany, was generously donated by Dar Al Dawa Development and Investment Company. Caffeine is 1,3,7-trimethyl-3,7-dihydro-1H-purine-2,6-dione. It is white or almost white, crystalline powder or silky crystals. It is sparingly soluble in water, freely soluble in boiling water and slightly soluble in ethanol. It is used as central nervous system stimulant (British Pharmacopoeia 2009).
• Methyl paraben was generously donated by Arab Pharmaceutical Manufacturing Company. Methyl paraben is methyl-4-hydroxybenzoate, prepared by the esterification of p-hydroxybenzoic acid with methanol. It occurs as colorless crystals or a white crystalline powder. It is odorless or almost odorless and has a slight burning taste (Rowe et al., 2009). Methyl paraben is very slightly soluble in water, freely soluble in alcohol and in methanol (British Pharmacopoeia 2009). It is widely used as an antimicrobial preservative in cosmetics, food products, and pharmaceutical formulations, either alone or in combination with …show more content…
HPMC is a partly O-methylated and O-(2-hydroxypropylated) cellulose. It is available in several grades that vary in viscosity and extent of substitution. Grades may be distinguished by appending a number indicative of the apparent viscosity, in mPa s, of a 2% w/w aqueous solution at 20°C. It is used as bioadhesive material; coating agent; controlled-release agent; dispersing agent; dissolution enhancer; emulsifying agent; emulsion stabilizer; extended-release agent; film-forming agent; foaming agent; granulation aid; modified-release agent; mucoadhesive; release-modifying agent; solubilizing agent; stabilizing agent; suspending agent; sustained-release agent; tablet binder; thickening agent; viscosity-increasing agent. In topical gels, it is used as an emulsifier, suspending agent, and stabilizing agent (Rowe et al.,