Drug name: VPL874C (Market name = Betatrix)
Possible indications = migraine prophylaxis, hypertension, coronary heart disease
Problem – want oral dosage form. - but has short half life (3-4hr)
Solution – oral dosage form with extended release which releases drug slowly so that the plasma concentrations are maintained at a therapeutic level for a prolonged period of time (usually between 8 and 12 hours).
Recent extended release formulations possible
pH-sensitive multiparticulate drug delivery system
- how it works: - a nano-suspension was made from with the drug, and then chitosan bead were made, which were degradable selectively in the colon
Advantage – area specific …show more content…
Irradiations were carried out up to a total given dose of 50 kGy and % gelation versus dose curves were constructed. About 40 kGy has been determined to be the lowest dose corresponding to maximum gelation (90%) (Savas¸ and Gu¨ven, 2001 in press). After irradiation, hydrogels obtained in long cylindrical shapes were cut into pieces of 3–4 mm thickness.
2.4. Loading of acti_e substance
For the investigation of active substance release behavior of PEO hydrogels prepared in this study, salicylic acid, phthalic acid and resorcinol were used as model substances. They were selected as representatives of aromatic structures possessing characteristic carbonyl and hydroxyl functional groups. Dry polymeric gels were loaded with active substance by immersion into aqueous solution of respective active substance at 25 °C for 1 day. Preliminary tests showed that 1 day is the minimum time to ensure complete swelling of gel and maximum loading of active substance.
Advantages – simple concept, cheap excipients, safe excipients, high drug loading, erodible, reduce possibility of ghost matrices, easy manufacture, different types of release is attainable.
Disadvantages – release of drug dependent on two diffusion processes – water and drug, eroding matrix can complicate the release profile, need for optimal rate-controlling polymers for different actives.