Percutaneous Penetration Of Liposomal Diclofenac Potassium Formulation, In Vitro And In Vivo

BACKGROUND: Diclofenac Potassium (DP) belongs to non-steroidal anti- inflammatory drugs (NSAIDs). DP has prominent anti-inflammatory analgesic and antipyretic properties. Oral therapy of DP is very effective, but the clinical use is often limited because of its potential to cause adverse effects such as irritation and ulceration of the gastro-intestinal (GI) mucosa, injury of the liver and kidney. It acts as anti- inflammatory and analgesic agents by inhibiting cyclooxygenases, which are key enzymes involved in the inflammatory response of the body. They catalyse the production of inflammatory prostaglandins (PG) from dietary arachidonic acids. PG is the important protection effect of gastric mucosa. Administration of NSAIDs via the dermal route can bypass these disadvantages of the oral route and may maintain relatively consistent drug levels for long-term therapy from a single dose. For liposomal formulation can penetrate through dermis efficiently, so it could carry DP through dermis after encapsulation.OBJECTIVE:1. To study in vitro and in vivo penetrability of topical liposomal diclofenac potassium formulation. Find the profile of DP distribution in vivo .2.Establish methods of using high performance liquid chromatography (HPLC) as the basic determination for DP and solid phase extraction (SPE), the important sample preparation method. 3.To provide the basic research for clinical application of liposomal DP formulation.METHOD:1.Establish and optimize the HPLC method for the determination of DP. 2.To product a stable DP liposomal formulation .3.Liposomal DP formulation permeation in vitro test though rat skin comparing with commercial gel formulation in modified Franz diffusion device were observed. 4.Using Waters(tm) HLB cartridge, we optimized the method for extraction of DP and establish the method for concentration of DP in vivo .5.Concentration distributions of DP in surface-muscles, deep-muscle, serum, livers and stomachs were determined by HPLC using SPE after topical administration of liposomal, common commercial gel formulation and oral administration in rats in vivo. 6. The changes of pathology in stomach after topical and oral administration were also observed.RESULTS:1.Establishment of HPLC method. The absorbance peak of DP is 281 nm. Using the selective procedure, the chromatogram of DP was determined .The retained time is around 11min and no interference was observed. 2.The DP liposomal formulation was produced. The particulate diameter was 345nm and the encapsulation ratio was 89.1%. 3. Establishment and optimization of SPE. Using 2-dimension elution method , the optimized procedure was determined: 1ml methanol→1ml water→1ml sample →1ml 60% acid methanol →basic methanol. Using SPE method, the recovery of DP in tissue is 90%~110%. 4.In vitro test. The liposomal formulation of DP could penetrate through rat skin more markedly comparing with the commercial gel formulation in vitro, especially after 4h .The loading amount of liposomal DP influence the result by phase. This result suggests that in a certain range 0.8~2mg/cm2, penetration amount couldn't raise in despite of raising loading amount simply. 5.In vivo test. The concentrations in surface-muscle and deep-muscle released from liposomal formulation are 3202.82ng/g and 1465.79ng/g respectively , which are higher and last longer than those from gel formulation (P<0.05~P<0.01) . The liposomal peak concentration reach later than that of oral formulation but it can last longer .The distribution in serum, liver, stomach are lower than that of oral formulation (P<0.05~P<0.01). 6. Pathology. Inflammatory reaction in stomach after topical liposomal formulation is less severity than that of oral formulation. CONCLUSION:1. HPLC determination method has been established and optimized .2. SPE method has been established and optimized so that it is more adapt to purify and concentrate DP in tissue .3.A stable DP liposomal formulation was produced. The particulate diameter was 345nm and the encapsulation ratio was 89.1%. 4. The...