Development of hot-melt extrusion as a novel technique for the ...

CHAPTER 5: AN IN VIVO AND IN VITRO TASTE MASKING EVALUATION OFBITTER MELT EXTRUDED APIs1.0 IntroductionThe taste of a pharmaceutical formulation has major influence on patient complianceto the medication and therefore the taste masking of bitter APIs is a major challengeespecially for the development of orally administered dosage forms in pharmaceuticalindustry [1] . In reality, most or many of the active pharmaceutical substances have either anunpleasant taste, such as bitterness, sourness or saltiness. Some of them may often cause anirritating mouth feeling, including metallic and/or spicy taste or astringency. For thesereasons, the need for a pleasant taste becomes a key aspect for patient palatability [2] . Tastemasking of various bitter active ingredients can be carried out using various techniquesdepending on the type of APIs and the type of formulation [3] .Currently, various taste masking methods are available. The most commonly usedconventional methods are film coating [4] and adding sugars, flavours or sweeteners[3]which are often limited due to regulatory requirements. Freeze-drying[1] , microencapsulation [5, 6] , fluidized bed coating [1] , high shear mixing [7] , supercritical fluids[8, 9]and spay drying [10] have been reported to be used as successful techniques for thepurposes of taste-masking various bitter active subtances. In addition to the afore mentionedconventional methods, different advanced and chemical taste masking approaches such asdrug complexation by cyclodextrines [11, 12] , ion exchange resins [13] , prodrugs and differentsalt formations [14] have been reported in the literature. Similarly, HME was introduced asuseful tool to produce polymeric extrudates with taste masking properties in a continuousprocess [15] . Different polymeric systems have already been implemented for taste maskingpurposes via the hot-melt extrusion (HME) processing and have been proved effective tastemaskingapproach by applying polymeric coating layer that creates a physical barrier aroundthe drug.Gryckze et al. (2011) successfully claimed taste masking of ibuprofen was achievedthrough intermolecular forces (e.g. hydrogen bonding) between the active substance and thepolymer matrix by processing oppositely charged compounds [2] . Later, similar results wereobserved by Maniruzzaman et al. (2012) where the authors successfully managed to mask thebitterness of paracetamol by applying the same mechanism [1] . In addition, solid dispersionswhere the drug is molecularly dispersed within the polymer matrix have shown effectivemasking of the drug‘s unpleasant taste. Successful taste masking requires development of85 | P a g e