Hydroxypropyl methylcellulose phthalate HPMCP

Some extended-release preparations are designed with a coating that responds to the acidity of its environment. The polymeric coating of the medicine is formulated for stability during oral delivery and for eventual solubility at the intended organ. The contrasting acidic content of the stomach and the more basic environment of the intestines enable these formulations to function. For example, hydroxypropyl methylcellulose phthalate (HPMCP) (Fig. 14.1.3) is an enteric... 

Figure 14.1.3 The repeating unit of the polymer hydroxypropyl methylcellulose phthalate (HPMCP).

Duloxetine hydrochloride, a novel anti-depressive, is known to be acid labile and, consequently, it has been formulated as an enteric-coated tablet. Interestingly, Jansen et al. [97] subsequently found that the drug was destabilised by degradation products within these enteric polymers. The authors found that succinyl and phthalyl residues from the hydroxypropyl methylcellulose acetate succinate (HPMCAS) and hydroxypropyl methylcellulose phthalate (HPMCP) formed... 

Hydroxypropyl methylcellulose phthalate (HPMCP) dissolves at pH greater than 5 and has two major grades, HP-55 and HP-55S. HPMCP shares the same problem as CAP and needs shellac to prevent permeation of water vapor and gastric fluids. 

Kim, I. H., Park, J. H., Cheong, I. W., and Kim, J. H. (2003), Swelling and drag release behavior of tablets coated with aqueous hydroxypropyl methylcellulose phthalate (HPMCP) nanoparticles, /. Controlled Release, 89,225-233. 

Ito R, Toida S. Studies on the teratogenicity of a new enteric coating material, hydroxypropyl methylcellulose phthalate (HPMCP) in rats and mice. Med Soc Toho-XJniv 1972 19(5) 453 61. 

In 1940, Eastman Kodak Company published a U.S. patent that provided one of the earliest de.scriptions of enteric coating of medicaments. The patent claimed the use of a cellulose derivative containing free carboxyl groups as an enteric film forming polymer. Specifically, the claimed enteric polymer was cellulose acetate phthalate (CAP) (34). Numerous enteric cellulose derivatives have been developed since this early account and these polymers remain as some of the most widely used for enteric coating applications. In addition to CAP these derivatives include cellulose acetate trimellitate (CAT), cellulose acetate succinate (CAS), hydroxypropyl methylcellulose phthalate (HPMCP), and hydroxypropyl methylcellulose acetate succinate (HPMCAS). The molecular structure of these polymers is depicted in Figure 1 with their respective substituent groups listed in the caption. 

Hydroxypropyl methylcellulose phthalate (HPMCP) Poly(methacrylic acid-co-methyl methacrylate) Poly(vinyl acetate phthalate) (PVAP)... 

Jansen PJ, Oren PL, Kemp CA, Maple SR, Baertschi SW. Characterization of impurities formed by interaction of duloxetine HC1 with enteric polymers hydroxypropyl methylcellulose acetate succinate (HPMCAS) and hydroxypro-pyl methylcellulose phthalate (HPMCP). J Pharm Sci 1998 87(1) 81—85. 

Cellulose phthalate hydroxypropyl methyl ether HPMCP hydroxypropyl methylcellulose benzene-1,2-dicar boxy late 2-hydroxypropyl methylcellulose phthalate methylhydroxypro-pylcellulose phthalate. 

Hydroxypropyl methylcellulose phthalate Synonyms HPMCP Hypromellose phthalate Definition A monophthalic acid ester of hydroxypropyl methylcellulose Properties Wh. powd., odorless, tasteless pract. insol. in water... 

As previously discussed, food effects are an important parameter for enteric-coated systems, especially for drugs, that are sensitive to food. Pancreatic enzyme-containing products fail when they come in contact too early with lipids, proteins, and carbohydrates present in food. The clinical efficacy of pancreatic enzymes formulated as enteric-coated tablets was investigated in man and dog [44], The enteric materials examined were hydroxypropyl methylcellulose phthal-ate (HPMCP), cellulose acetate phthalate (CAP), and the methacrylic acid copolymer USP/NF Type C. In vivo behavior monitored by x-ray scintigraphy showed clear differences between the three coating formulations. HPMCP-coated products adhered to the gastric mucosa, whereas CAP and methacrylate copolymer... 

The enteric materials examined were hydroxypropyl methylcellulose phthal-ate (HPMCP), cellulose acetate phthalate (CAP), and the methacrylic acid copolymer USP/NF Type C. In vivo behavior monitored by x-ray scintigraphy showed clear differences between the three coating formulations. HPMCP-coated products adhered to the gastric mucosa, whereas CAP and methacrylate copolymer... 

Cellulose esters or ethers such as methylcellulose (MC), ethylcellulose (EC), hydroxyethyl cellulose (HEC), hydroxypropyl cellulose (HPC), hydroxypropyl methylcellulose/hypromellose (HPMC), hypromeUose phthalate (HPMCP), hypromellose acetate phthalate (HPMCAP), hypromellose acetate succinate (HPMCAS), cellulose acetate (CA) and derivates Poly (methyl) methacrylates (Eudragit L, S, E, RS/ RL)... 

---