Modified-Release Delivery Systems
Larry L. Augsburger, Stephen W. Hoag in Pharmaceutical Dosage Forms, 2017
Frequently used materials for enteric coating are polymeric acids with free carboxyl groups that confer gastric resistance. They include anionic polymethacrylates (copolymerisate of methacrylic acid: methylmethacrylate or ethyl acrylate, Eudragit L 30 D-55, Eudragit FS 30 D, or Eudragit-L100, with a pH value of aqueous dispersion of ~3.05) and cellulose-based polymers (i.e., hypromellose acetate succinate [HPMCAS], with pH about 3.85) or hypromellose phthalate (HPMCP), aqueous cellulose acetate phthalate (Aquateric), or polyvinyl derivatives such as polyvinyl acetate phthalate (Coateric). Since aqueous dispersions of Eudragit L 100 have high film-forming temperatures of about 85°C, mixing with the softer Eudragit L 30 D 55 makes it possible to reduce the film-forming temperature to about 40°C, which is a more acceptable range especially when hard gelatin capsules and HPMC capsules are coated. For modulation of drug release in pH 5.5 to 7.0, further mixing with Eudragit NE 30 D and FS 30 D is an acceptable option. Explicitly aqueous dispersions for enteric coating (Eudragit L 30 D-55) and colonic coating (Eudragit FS 30 D) of HPMC and hard shell gelatin capsules have been investigated.31,32 Apart from enteric film formers, other enteric film coating components include plasticizers (i.e., diethyl phthalate, triacetin), anti-adhesion agents, colorants, pigments, solubilizers, and dispersing agents. To these may be added viscosity-enhancing suspension stabilizers designed to retard the sedimentation of undissolved excipients or dispersed film formers.
Binders in Pharmaceutical Granulation
Dilip M. Parikh in Handbook of Pharmaceutical Granulation Technology, 2021
HPMC is one of the most widely used excipients in general and is also frequently used as a tablet binder. It is also known as hydroxypropyl methylcellulose (HPMC) and is formed by reacting alkali cellulose with methyl chloride and propylene oxide to yield a mixed substitution cellulose ether. Various substitution ratios and MW grades are available. Primarily low-viscosity grades with substitution type “2910” (28−30% methoxy groups by weight and 4−12% hydroxypropyl groups) are used as tablet binders (Table 4.2). These grades are also very popular for film coating formulations. HPMC is listed in the USP/NF, Ph. Eur., JP, and FCC.
Preservation of solid oral dosage forms
R. M. Baird, S. F. Bloomfield in Microbial quality assurance in cosmetics, toiletries and non-sterile Pharmaceuticals, 2017
Aqueous film coating procedures use solutions of cellulosic polymers which may readily support microbial growth (Banker et al. 1981). Where large batches of solution are prepared in advance, preservatives may be added to prevent subsequent microbial proliferation in pumps, lines and coating equipment. The results of Fassihi et al. (1981) suggest that a preserved film coating could protect finished tablets from possible microbial growth during storage.
Development of metoprolol tartrate-loaded sustained-release pellets: effect of talc on the mechanism of drug release
Published in Pharmaceutical Development and Technology, 2018
Yuli Wang, Meiyan Yang, Ruifang Shen, Shuai Shao, Lu Chen, Wei Gong, Li Shan, Chunsheng Gao
However, a major problem encountered during the layering or coating process is the sticking of the layered or coated substrates because of the tackiness of the drug solution or the extremely high elongation of the polymer film16. This tackiness causes a tremendous handling problem as the layered or coated substrates stick to each other or to the coating chamber. Sometimes, irreversible agglomeration of pellets or loss of the complete batch can occur. To reduce the tackiness of the polymeric film coating formulations, facilitate the process of coating and promote the dispersion of the solution on the solid substrate, insoluble additives, such as talc, glycerol monostearate, magnesium stearate, silicon dioxide and kaolin are used as antiadherents17–20. The inclusion of these insoluble additives in coating formulations may affect processing parameters, the physical appearance of the final product, polymer adhesion, the permeability of the film and even the dissolution characteristics of the coated solid21. Talc, a hydrophobic compound, is one of the most commonly used antiadherents. However, most research focuses on its functions in film coating. Moreover, several studies have shown that the addition of insoluble additives in coating dispersions improves or retards drug release. In most cases, researchers only have hypotheses or theories to explain the mechanism behind these results. Therefore, the mechanism of influence of talc on drug release needs to be studied in detail.
Application of a tablet film coating model to define a process-imposed transition boundary for robust film coating
Published in Pharmaceutical Development and Technology, 2018
Sander van den Ban, Kendal G. Pitt, Marshall Whiteman
A scientific understanding of interaction of process, product formulation, film coat, and equipment, is important to enable design and operation of an industrial scale pharmaceutical film coating process that is robust and provides the level of control required to consistently deliver quality film coated product. A thermodynamic film coating model was used to evaluate film coating process performance over a wide range of film coating loads from pilot scale to commercial scale (2.5–400 kg). Heat loss transfer coefficients were determined for a wide range of equipment from pilot to industrial scale process. More recently built film coating equipment benefitted from an enhanced insulation design to limit heat loss. An approximate process-imposed transition boundary, for operating in a dry to a wet environment, was derived for relative humidity and exhaust temperature. This was used to understand the impact of the film coating process on product formulation and process control requirements. This approximate transition boundary may aid in an enhanced understanding of risk to product quality, application of modern QbD based product development, technology transfer and scale-up, and support the science-based justification of CPPs.
Dual effect biodegradable ciprofloxacin loaded implantable matrices for osteomyelitis: controlled release and osteointegration
Published in Drug Development and Industrial Pharmacy, 2018
Ahmed F. Hanafy, Hany S. M. Ali, Samar N. El Achy, EL-Sayed E. Habib
In the current study, PLLA based, CPX-loaded implantable matrices (CPX-IMs) were manufactured using injection molding. This technique represents a suitable method to fabricate implants with uniform three-dimensional shape and good mechanical strength [9,10]. The developed matrices were further coated with hot melt dip coating procedures. Dip coating technique was utilized to coat CPX-IMs instead of conventional film coating through spraying organic biodegradable polymer coating solution for several reasons. Dip coating provides a faster coating method for CPX-IMs [11]. Additionally, the inclusion of large particle porogens of specific sizes in coats cause problems of spray gun clogging in film coating. Moreover, melt dip coating allows the building of three-dimensional coat structure of few millimeters thickness [12] providing external porous structures with a reasonable depth suitable for cell attachment. Whereas, film coating could achieve only a few micrometers of coat that would not allow enough support for cell attachment [10]. The absence of organic solvents from the hot melt dip coating technique exclude a very tedious step of getting rid of them, even small amount of residues can affect cellular growth as well as nearby tissues and can also affect porogen particle size [10]. Nevertheless, dip coating technique is affected by many process parameters that must be considered and optimized to prevent variability and improve reproducibility [13].
Related Knowledge Centers
- Capsule
- Excipient
- Polymer
- Shelf Life
- Stomach
- Medication
- Dosage Form
- Tablet
- Opacifier
- Modified-Release Dosage