Development Of Controlled Release Tablet Formulation Using Hydrophilic Polymer Matrix Systems

To  develop large  diameter, non-disintegrating controlled release tablet formulations using hydrophilic polymer matrix systems for pH sensitive low solubility drugs.

Formulations containing a pH solubility sensitive drug and a combination of hydrophilic polymers (HPMC and Polyox) and alkalizers (such as calcium  carbonate, magnesium oxide and sodium bicarbonate) were designed and manufactured using direct compression or roller compaction  followed  by compression using rotary  tablet press. The investigation was aimed to  provide an  alkaline  micro-environment to a chernical entity which has a very  poor solubility up to pH  of 6.8. The  tablets were subjected to prolonged exposure  to various pH environments (pH range 1.0 to 7.4) and studied for  effect of various pHs on in- vitro release  profile using USP dissolution apparatus Ill method. Selected  formulations were tested  for physical appearance, dissolution, content and impurities after storage at 40°C/75%RH for up to 6 months.

Large, non-disintegrating  controlled release tablet formulations using hydrophilic polymer matrix systems were designed and developed to release the drug for 7-9 hours (Formula. 1 A/2A) and 10-12  hours (Formula 2A/2B) respectively with zero to pseudo zero order release profiles. No significant changes in physical appearance, stability and dissolution were observed from the stability samples. The data showed significant influence of the alkalizers on the dissolution profile of the  tablets. The  molecular weights and type of  hydrophilic polymers also influence the tablet strength and drug release mechanism (i.e. erosion or diffusion) from  the  matrix tablets during in-vitro dissolution. With suitable combination of excipients, floating tablets in dissolution fluids were produced.