Among the various research works going on nowadays, designing of controlled release dosage form is of great importance. For the development of suitable controlled release dosage form, a proper matrix needs to be forme...Among the various research works going on nowadays, designing of controlled release dosage form is of great importance. For the development of suitable controlled release dosage form, a proper matrix needs to be formed from which the drug release generally occur by polymer swelling, polymer erosion, drug dissolution/diffusion mechanism. HPMC （hydroxy propyl methyl cellulose）, also known as hypromellose, is one of the best known cellulosic polymers used in the development of controlled released drug delivery. It is available in various grades. Cellulosic polymers are ingredients that contain units linked together which help to retain water. Due to its high water absorptive capacity, it acts as an excellent hydrophilic gel forming polymer. HPMC generally hydrates on the outer surface to form a gelatinous layer which is critical to prevent wetting and rapid drug release from the matrices. If the drug is sparingly soluble in the system, the release of drug from the system is slow and helps in formulation of controlled release dosage form. In the ophthalmic dosage form, HPMC is used as a matrix that swells and expands after absorbing water and expand the thickness of the tear film.展开更多
文摘Among the various research works going on nowadays, designing of controlled release dosage form is of great importance. For the development of suitable controlled release dosage form, a proper matrix needs to be formed from which the drug release generally occur by polymer swelling, polymer erosion, drug dissolution/diffusion mechanism. HPMC （hydroxy propyl methyl cellulose）, also known as hypromellose, is one of the best known cellulosic polymers used in the development of controlled released drug delivery. It is available in various grades. Cellulosic polymers are ingredients that contain units linked together which help to retain water. Due to its high water absorptive capacity, it acts as an excellent hydrophilic gel forming polymer. HPMC generally hydrates on the outer surface to form a gelatinous layer which is critical to prevent wetting and rapid drug release from the matrices. If the drug is sparingly soluble in the system, the release of drug from the system is slow and helps in formulation of controlled release dosage form. In the ophthalmic dosage form, HPMC is used as a matrix that swells and expands after absorbing water and expand the thickness of the tear film.
