Development of enteric-coated calcium pectinate microspheres intended for colonic drug delivery

Development and in vitro/in vivo evaluation of Zn-pectinate microparticles reinforced with chitosan for the colonic delivery of progesterone

“…The PG spectrum shows two typical intense bands at 1662 and 1699 cm À1 corresponding to stretching vibrations of the C¼O groups of PG (Liu et al, 2007). The spectrum of pectin ( Figure 2B) shows a broad band between 3600 and 3000 cm À1 due to stretching of its OH groups in addition to two important bands: low-intensity band at 1740 cm À1 and a stronger one at 1639 cm À1 which are attributed to the esterified and non-esterified carboxyl groups of pectin, respectively (Maestrelli et al, 2008a). Chitosan spectrum ( Figure 2C) shows the characteristic bands of amidic C¼O stretching at 1652 cm À1 and of amidic N-H bending at 1580 cm À1 (Bigucci et al, 2008).…”

“…C and 210 C due to its endothermic transition and melting process, respectively (Auriemma et al, 2013). Also, a small exothermic deviation from baseline at around 240 C was noticeable, indicating the start of pectin chains depolymerization (Maestrelli et al, 2008a). Chitosan ( Figure 3C) shows a broad endothermic peak at $95 C due to the evaporation of absorbed water and a sharp exothermic peak starting at 280 C and gaining its maximum at 310 C due to chitosan degradation (Borges et al, 2005).…”

“…However, some formulations, namely those made with chitosan concentration50.5% or pectin/PG ratio of 2:1, possessed slightly higher ER and lower C values, presumably due to depression of one side of their weak surface during drying (Das et al, 2011). Maestrelli et al (2008a) also demonstrated that lower degrees of cross-linking yielded microspheres with irregular shape.…”

“…The amidated low methoxy (LM) pectin, in which some of the carboxylic acid groups are amidated, is more tolerant to pH variations which makes it an appropriate candidate for the design of colon-targeted drug delivery systems (Oliveira et al, 2010). However, pectin high aqueous solubility and swelling properties are considered the major drawbacks that lead to rapid drug release during transit in the upper GIT (Maestrelli et al, 2008a;Wei et al, 2014). This necessitates the combination of pectin with other polymers or targeting strategies and also highlights the need for cross-linking of pectin chains to maintain the integrity of the dosage form until it reaches the colon (Mura et al, 2003).…”

“…Colon-specific drug delivery systems have gained increasing interest in the last decades due to the well-recognized importance of this region of the GIT, both for local and systemic administration of conventional and labile drugs (Yang et al, 2002;Maestrelli et al, 2008a;Bai et al, 2015). Drugs which are destroyed by the stomach acid or metabolized by pancreatic enzymes are minimally affected in the colon (Vervoort et al, 1998).…”