ALZA CORP

Osmotic Pressure Controlled Oral Tablets. Alza Corp. has developed a system that is dependent on osmotic pressure developed within a tablet. The core of the tablet is the water-soluble dmg encapsulated in a hydrophobic, semipermeable membrane. Water enters the tablet through the membrane and dissolves the dmg creating a greater osmotic pressure within the tablet. The dmg solution exits at a zero-order rate through a laser drilled hole in the membrane. Should the dmg itself be unable to provide sufficient osmotic pressure to create the necessary pressure gradient, other water-soluble salts or a layer of polymer can be added to the dmg layer. The polymer swells and pushes the dmg solution through the orifice in what is known as a push-pull system (Fig. 3). The exhausted dmg unit then passes out of the body in fecal matter. 

Ophthalmic dmg dehveiy systems (qv) have been developed to dehvei controlled dmg quantities for a prolonged time (up to seven days) to the eye, eg, pilocarpine [92-13-7J (17). Alza Corp. in conjunction with Ciba-Geigy Corp. originally marketed such a product known as Ocusert to treat glaucoma. 

Alza Corp. has also developed an iatrauteriae device, Progestasert, designed to release progesterone [57-83-0] by diffusion through a rate-controlling membrane for up to one year. The dmg reservoir is built into a T-shaped device that is inserted intravaginaHy (15). 

This equation describes the steady-state, or zero-order, release of the dmg. When the dmg completely dissolves, its concentration within the system begins to dilute, and the release rate foUows a parabohc decline with time (102). Acutrim (ALZA Corp.), dehvering phenylpropanolamine hydrochloride [154-41 -6] for appetite suppression, is an example of an elementary osmotic pump. 

Database of Alzet Pubbcations, ALZA Corp., Palo Alto, Calif., 1992. 

Drug solutions and implantation of osmotic mini-pumps Physostigmine hemisulphate and procyclidine hydrochlorid were obtained from Sigma (St.Louis, U.S.A.), scopolamine hydrobromid from Merck (Darmstadt, Germany), atropine sulphate was obtained from ACF (Amsterdam, The Netherlands), and diazepam from Roche (The Netherlands). HI-6 was made available by the Defence Research Establishment, Suffield, Canada. Soman (O-pinacolyl methylphosphonofluoridate) was synthesised at TNO. Alzet Osmotic Mini-pumps with a constant delivery rate of 0.55 pl/hr (Model 2002, Alza Corp., Palo Alto, USA) were used to deliver PYR, PHY and SCO. The vehicle consisted of 20% propylene glycol, 10% ethanol and 70% water. The pumps were implanted subcutaneously under isoflurane/02 inhalation anesthesia. 

Elementary osmotic pump (ALZA Corp.) Once-daily osmotic tablet with solid active agent... 

Push-Pull osmotic delivery system (ALZA Corp.) Multilayered tablet for drugs with low to high solubility... 

In parenteral therapy, the subcutaneously implantable, osmotic mini-pumps developed by the Alza Corp. are used widely in experimental animal studies. The DUROS implant pump is a modified version of the Alzet pumps and was developed specifically for the controlled delivery of peptides and proteins (see Section 4.6.1.2). Osmotic mini-pumps, such as the Oros osmotic pump, are also available for controlled... 

Testosterone (T) Male (25-69) Upper buttocks, upper arm, back D-Trans (Alza Corp.) Pharmacokinetic parameters Similar pharmacokinetic profiles between sites ... 

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