A drug loading up to 55% w/w was achieved on Purolite® C100MRNS, which was independent of pH, temperature and stirring speed of the loading medium. The drug-resin complex was characterized by FTIR for functional group interactions of both resin and drug. The amorphous nature of drug-resin complex was characterized by powder laser diffraction. There was burst and incomplete release from uncoated resinates and it was probably due to an equilibrium between counter ions of release medium (H+, Na+) and exchanged drug molecules. Moreover, drug release was also un-changed up to three months of storage at 40ºC/ 75% RH and 20ºC/ 60% RH. Another challenge with liquid controlled release formulations was the enteric coating due to the stability concerns and the drug release in the stomach. Drugs were first ionically complexed with Amberlite® IR 69F, then coated with the appropriate pH-dependent polymer (Eudragit® L30D-55). The USP criteria for such formulations, is less than 10% drug released in 0.1N HCl over two hours. The drug loading was only 7% w/w for 72 hours, when resin was regular shape (spherical particles) with a size of 300 to1100 µm. The drug loading was significantly increased up to 55% w/w when resin was milled by ball milling and particle size was reduced to 45-150 µm. The drug release was less than 10% in 250 ml of 0.1 N HCl within two hours and more than 70% release during first hour in pH 6.8 sodium phosphate, confirmed the enteric drug delivery system. The drug-resin complex was stable at 40ºC and 60ºC for a period of one week. Furthermore, the drug release remained un-changed over 3 months storage at 40°C/75% RH and 25ºC/60% RH. Furthermore, there was no agglomeration of coated particles during one-week storage at temperature of 2-8°C after its reconstitution. The model drugs (diltiazem HCl and tramadol HCl) were loaded on Purolite®C100CaMRNS (cation exchange resin) by a batch process. The drug-resin complexes were characterized for functional group interactions with FTIR and crystalline state of drug with P-XRD. The release was successfully controlled by the Eudragit® NE30D, 25 % coating level (% weight gain) with a curing procedure at 60°C for 12 hours. The complete drug release for both drugs was achieved when the media was mixed with 300 mM KCl. In reservoir multiparticulate systems, lipophilic drug such as ibuprofen, is leached out in the coating polymer during the storage of the formulation at 40 ºC/75% RH. The leaching was happened when the formulations were coated with an aqueous polymer dispersion like Aquacoat® ECD and Kollicoat® SR 30D. This ultimately affects the robustness of the reservoir systems.In order to prevent this drug leaching into the coated polymer, an intermediate seal coating of (HPMC) or (PEG) was applied. At the same time, the additional seal coating increases the production costs of the delivery system. So therefore, there was a need to address the leaching of the lipophilic drug into the coated polymer with help of drug-resin complex. The drug Ibuprofen was successfully loaded/complexed with anion exchange resin Purolite® A430MR and Duolite TM AP143/1093. The particle size of drug-resin complex was reduced to 10.65 ± 0.55 µm using Dyno mill. The drug-resin complex was layered on NP core 710-850 µm in a fluidized bed coater. The layering formulation was prepared with 20% HPMC E5 as a binder w/w of drug-resin complex. There was no increased drug release observed during first hour of the release, when formulation was stored for one-month at 40 ºC/75% RH and 25 ºC/60% RH. This confirms the prevention of leaching of lipophilic drug into the Kollicoat® SR 30D coating during storage with help of drug-resin complex layering.