Ultraviolet Spectroscopy Of Verapamil Hydrochloride Lab Report Solution

RESULTS AND DISCUSSION:
Ultraviolet spectroscopy of Verapamil hydrochloride at λmax of 278 nm in pH 1.2 buffer was found to be linear in range of 20 – 80 µg/ ml. The method was validated and found to be precise, specific and accurate.
The tablets of Verapamil hydrochloride were prepared by press coating technique showing sustained release for 24 h for once daily dosing with a lag phase of 4 - 6 h. The optimum ratios and type of polymers and other excipients were chosen to produce gastroretentive floating tablets to meet the desired objective of lag phase and sustained release. Placebo formulations L1 and L2 differed in the composition of core tablet where L1 contained Kollidon SR and L2 contains Methocel K15M. The press coat contained Eudragit
Harder tablets showed good integrity but longer floating lag time while tablets with lower hardness either disintegrated or capped but showed shorter floating lag time. Therefore, hardness of core was adjusted to 5 – 6 kg/cm2 and hardness of press coated tablets was adjusted to 6 – 7 kg/cm2 for optimum floating. Thus, L3 and L5 containing Methocel K4M and Compritol ATO in core respectively and Methocel K4M in coat of the tablets, showed good floating behavior and integrity and were chosen further for the study by incorporating the drug. Verapamil Hydrochloride was incorporated in L3 and L5 to produce V1 and V2. Both these formulations showed a floating lag time of less than 5 mins and floating time of 24 h with a prolonged release but failed to show desired lag phase (fig.1). The decrease in floating lag time can be attributed to use of Compritol ATO 888 (low density polymer) in the core. The absence of lag phase during drug release can be attributed to presence of less amount of coat than core and effect of pressure generated by sodium bicarbonate on coat of the tablet. Hence, to achieve complete lag phase and floating behaviour, V2 was modified by reducing the amounts
The developed tablets complied with the test for uniformity of weight as per I.P. The hardness of the core tablet was adjusted to 5 – 6 kg/cm2. The hardness of the tablet after press coating the core tablet was 6 – 7 kg/cm2. The developed tablet formulations showed friability less than 1% w/w. The drug content of tablets was found to be within the limits as per I.P. The optimum formulation showed floating lag time of less than 10 mins and tablets remained floating for 14 to 16 h. The optimized tablet showed 250% increase in weight after swelling (fig.7a, 7b) due to swelling properties of the polymer and can attribute to buoyancy of the tablets. The images (fig.8) are of the optimized formulation and show the desired lag time of 4 - 6 h as indicated by diffusion of Amaranth dye. In-vitro release studies of the optimized formulation, V22 showed lag phase of 4 – 6 h followed by drug release as per limits specified by USP (fig.5) for once daily dosing. The optimized formulation followed zero order release kinetics. As the amount of swelling polymer is reduced, the non-swelling polymer proportionately increases, thus the drug release by diffusion is hampered and follows zero order type release kinetics. The developed formulation was found to be stable as per ICH guidelines for period of three