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1 FORMULATION OPTIMIZATION AND EVALUATION OF LIPOSOMAL GEL OF PREDNISOLONE BY APPLYING STATISTICAL DESIGN Varde Neha M*, Thakor Namita M, C.Sini Srendran, Shah Viral H Sigma Institute of Pharmacy, Bakrol, Vadodara *Corresponding Address: id: varde_neha@yahoo.com, Phone no. : ABSTRACT Liposomal carriers, well known for their potential in topical drug delivery have been chosen to help Prednisolone molecules in the skin layers. In the present work statistical study for the formulation of liposomes for topical delivery of Prednisolone using the factorial design approach was undertaken. Amount of Soya Lecithin, DPPS and cholesterol (CH) were taken at three different levels and liposomes were prepared using film hydration technique. Gels containing liposomes (optimized batch) were prepared in Carbopol 940P and were characterized for rheology, spreadability and permeation through the rat skin. Results of regression analysis revealed that vesicle size and entrapment efficiency were dependant on the cholesterol and lipid concentration. Rheological studies of all liposomal gels prepared with 1%, 1.5%, and 2% w/w carbopol gave a clear idea of concentration of carbopol required. Liposomal dispersion and gels were found to increase the skin permeation and deposition compared to control and marketed gel. Liposome dispersion and gel formulation were found to be stable for 60 days. Key words: Prednisolone, Thin Film Hydration method, Liposomes, Box Benhken design, Carbopol Gel. 1. INTRODUCTION Topical drug delivery is an attractive route for local and systemic treatment. The delivery of drugs onto the skin is recognized as an effective means of therapy for local dermatologic diseases and other diseases. Rheumatoid arthritis is a chronic auto immune disease characterized by joint synovial inflammation and progressive cartilage, bone destruction leading to gradual immobility. Drugs useful in treatment of rheumatoid arthritis are classified as first line agents having Non-steroidal anti inflammatory drugs and steroidal anti inflammatory drugs. Prednisolone (11β)-11, 17, 21-trihydroxypregna-1, 4-diene-3,20-dione is a steroidal drug with predominant glucocorticoid and low mineral corticoid activity. It is mainly used for the treatment of a wide range of inflammatory and autoimmune diseases such as asthma, multiple sclerosis, rheumatoid arthritis, autoimmune hepatitis etc. Prednisolone is also known as disease modifying antiarthritic drugs because of its anti inflammatory action by inhibiting gene transcription for COX-2, cytokines, cell adhesion molecules, and inducible NO synthetase. When steroidal anti inflammatory drugs such as prednisolone are given orally results in systemic side effects like bone loss, increased susceptibility to infection, osteoporosis, peptic ulcers and buffalo hump. Parental route of administration results in rapid clearance rate of drug which ultimately compels invasive and frequent administration of drug. Attempts will be made in developing and characterizing a specific drug delivery system targeting drugs to synovium or specific tissues which in turn increase drug efficacy with minimum extra synovial toxicity in arthritis. The main objective of the study is to formulate and evaluate prednisolone liposomal gel formulation for effective topical pharmacotherapy in treatment of rheumatoid and other diseases. 2. MATERIALS AND METHODS 2.1 Materials: Prednisolone (Mercury Laboratories Pvt. Ltd., Vadodara), DPPS(Lipoid GmbH, Germany) and saturated soya lecithin were a generous gift from Novastell,France. Cholesterol (CHOL), Carbopol 940P was purchased from S.D. Fine Chemicals, Mumbai, India. All other chemicals used were of HPLC or analytical grade. 2.2 Liposome preparation: Aqueous liposomal formulations were prepared by conventional lipid film hydration method. Different weight ratio of phospholipids: choleseterol were weighed and dissolved in chloroform: methanol mixture (2: 1 v/v) in 250 ml round bottom flask. A thin film was formed on the inner side of round bottom flask by evaporating organic solvent under vacuum in rotary evaporator at C. Subsequently, the flask was kept overnight under vacuum to ensure the complete removal of residual solvent. The dry lipid film was hydrated with 20 ml phosphate buffer solution (ph 7.4) containing at phase transition temperature of different lipids. The dispersion was left undisturbed at room temperature for 2-3 h to allow complete swelling of the lipid film and hence to obtain vesicular dispersion. Volume 1(2) March-April 2013 Page 180

2 2.3 Effect of variables: To study the effect of variables on liposome performance and characteristics, different batches were prepared using 3 3 Box Behnken design. Amount of Soya Lecithin, DPPS and Cholesterol were selected as three independent variables. Mean Vesicle size, %EE and %Cumulative drug release in the rat skin were selected as dependent variables. Amount of Prednisolone was kept constant Preparation of Liposomal Dispersion Formulation Using Experimental Design: Prednisolone liposomal formulations were prepared by conventional thin-layer hydration or rotary evaporation technique using Box- Behnken design. A three-factor, three-level Box- Behnken design was used for constructing a second-order polynomial models using Design Expert (Version ; Stat-Ease Inc, Minneapolis, Minnesota). A design matrix comprising 15 experimental runs was constructed, for which the nonlinear computer-generated quadratic model is defined as: 2 Y = b 0 + b 1 X 1 + b 2 X 2 + b 3 X 3 + b 12 X 1 X 2 + b 13 X 1 X 3 + b 23 X 2 X 3 + b 11 X 1 + b 22 X b 33 X 3 where Y is the measured response associated with each factor level combination; b 0 is constant; b 1, b 2, b 3 are linear coefficients, b 12, b 13, b 23 are interaction coefficients between the three factors, b 11, b 22, b 33 are quadratic coefficients computed from the observed experimental values of Y from experimental runs; and X 1, X 2 and X 3 are the codes of independent variables. The terms X 1 X 2 (i = 1, 2 or 3) represent the interaction effect. The independent variables selected were the amount of the Soya lecithin(x 1 ), 1,2-Dipalmatoyl-sn-glycero-3-phospho-Lserine(DPPS) (X 2 ) and Cholesterol (X 3 ). The dependent variables were Mean Particle size (Y 1 ), EE % (Y 2 ) and percentage cumulative drug permeated (Y 3 ) with constraints applied on the formulation of liposome. The concentration range of independent variables under study is shown in Table 1 along with their low, medium and high levels, which were selected based on the results from preliminary experimentation. The concentration range of soya lecithin (X 1 ), DPPS (X 2 ) and Cholesterol (X 3 ) used to prepare the 15 formulations and the respective observed responses are given in Table 2. Table 1: Variables in Box- Behnken design for preparation of Prednisolone liposome Code Independent variables Low (-1) Medium (0) High (+1) X 1 Soya lecithin (mg) X 2 DPPS (mg) X 3 Cholesterol (mg) Dependent variables Goal Y 1 Mean vesicle size (nm) In Range Y 2 %Entrapment Efficiency Maximum Y 3 %Cumulative drug Release Maximum Formulation table: Table 2: Formulation composition of batch F1 to F15 Ingredients(mg) F1 F2 F3 F4 F5 F6 F7 F8 F9 F10 F11 F12 F13 F14 F15 Prednisolone Soya lecithin DPPS Cholesterol Organic solvent (ml): Chloroform Methanol Characterization of liposomes: Mean Vesicles shape, size, and size distribution and zeta potential: Liposome vesicles were visualized using optical microscope. Digital micrograph and soft imaging viewer software were used for image capture and analysis. The vesicles size, size distribution and zeta potential were determined using a computerized inspection system with zetasizer (dynamic light scattering method, HAS 3000; Malvern Instruments, Malvern, United Kingdom) Lamellarity: The lamellarity of the liposomes was determined by CLSM (Confocal laser scanning microscopy) study. Volume 1(2) March-April 2013 Page 181

3 2.4.3 Encapsulation efficiency: Liposome encapsulation efficiency was determined from the amount of entrapped drugs using the ultracentrifugation technique. Briefly, total amount of drug was determined after having dissolved and disrupted drug-loaded liposomes in ethanol or Triton X-100 using an ultrasound bath for 10 min. Then, sample was centrifuged at 20,000 rpm for 50 min. The free drug was determined in the supernatant at nm with a UV visible spectrophotometer. The drug encapsulation efficiency (EE %) was calculated as follows: EE %= Total amount of drug incorporated Free amount of drug (supernant) 100 Total amount of drug In- vitro drug release study: In-vitro drug release of drug from the liposomal formulation was evaluated using the franz diffusion cell technique. 5 ml aliquot of liposomal suspension was placed in the donor compartment. Hairless Rat skin was used as the diffusion membrane. Perfect sink conditions prevailed during the drug release studies and the entire system was kept at 32±0.5 º C under continuous magnetic stirring at 50 rpm. Samples (5 ml) of the receptor compartment was taken at various time intervals and assayed for drug concentration by spectrophotometric method. 2.5 Preparation of liposomal gel: The appropriate amount of carbopol 940P was weighted and added slowly in a citrate buffer solution (ph 5.0), under constant stirring by a paddle stirrer. After addition of the full amount of solid material, the gel was allowed to swell under moderate stirring for at least 24 h or until fully swollen and transparent. Other ingredients, such as 15% w/v polyethylene glycol-400 (PEG-400) and triethanolamine (0.5% w/v), were added to obtain homogeneous dispersion of gel and sodium benzoate (0.5% w/v) was added in the buffer used for gel preparation. Liposomal gel formulations were prepared by mixing the liposomal dispersions with the gels in the ratio of 1:5 (w/w) (liposome dispersion/gel). 2.6 Characterization of liposomal gel: Optimized formulation of the liposomal suspension is converted to the gel formulation and its physical and chemical characterization is carried out by following tests. The carbopol 940P gel formulations were prepared using 1%, 1.5% and 2% carbopol concentration Physical examination: The prepared gel formulations were inspected visually for their colour, homogeneity, consistency and spreadability. Clarity was determined by using clarity chamber with black and white background ph: The ph values of 1% aqueous solutions of the prepared gels were measured by a ph meter. The glass electrode was calibrated with two standard buffers (ph of 4.00 and 9.00).The preparation was left for about 15 min for attaining equilibrium while measuring Viscosity: Viscosity of prepared gels was measured by Brookfield Viscometer. Apparent viscosity was measured at 25 C and rotating the spindle at 1.5 rpm Content uniformity: Gel formulation (100 mg) was dissolved in methanol and filtered. The volume was made to 100 ml with methanol. The resultant solution was suitably diluted with methanol and absorbance was measured at nm of drug using Shimadzu 1700 UV Visible spectrophotometer In-vitro drug permeation study: An essential parameter in the evaluation of drug delivery is the rate at which the drug is released from the carrier. Skin permeation study with drug-containing liposomal formulation was carried out using modified Franz diffusion cell. Full thickness abdominal skin of male Wister albino rats weighing 140 to 200 g was used for the skin permeation. Briefly, to obtain skin, animal was sacrificed. Hair from the abdominal region was carefully removed and an excision in the skin was made. The dermal side of the skin was thoroughly cleaned of any adhering tissues. Dermis part of the skin was wiped 3 to 4 times with a wet cotton swab soaked in isopropanol to remove any adhering fat. The skin specimen was cut into appropriate size after carefully removing subcutaneous fat and washing with normal saline. Skin was mounted in a modified Franz diffusion cell, kept at 32±0.5ºC. The known quantity of gel equivalent to 10 mg of drug was spread uniformly on the skin on donor side. ph 7.4 phosphate buffer was used as the acceptor medium, from which samples were collected at regular intervals. An equal amount of acetonitrile was added to the collected samples to precipitate skin protein prior to estimate with UV spectroscopy. All permeation experiments were repeated three times and data were expressed as mean of three experiments ± standard deviation (SD). 2.7 Stability study: Stability studies of liposomal suspension and gel were done for 3 months under conditions required by guidelines of the ICH. Accelerated stability studies were performed by keeping the temperature 4-8 C, 25±0.5 C and 60 ± 5 %RH (relative humidity). The samples were taken at the interval of 0, 30, 60 days. The stability was evaluated by comparing the particle size and %Entrapment Efficiency for suspension. The parameters like viscosity and percentage cumulative permeation of drug were evaluated for gel. Volume 1(2) March-April 2013 Page 182

3. RESULT AND DISCUSSION Figure 1: Microscopic Image of Liposome (a) Yellow box: MLV, (b)brwon box: SUV and (c)blue box: LUV A B C Figure 2: Microphotographs corresponding to multilamellar liposomes

Statistical data: Responses of different batches obtained using box benhken design are shown in Table 3 obtained data were subjected to multiple regression analysis using Design Expert (Version 8.0.7.

4 3. RESULT AND DISCUSSION Figure 1: Microscopic Image of Liposome (a) Yellow box: MLV, (b)brwon box: SUV and (c)blue box: LUV A B C Figure 2: Microphotographs corresponding to multilamellar liposomes by CLSM using transmitted channel: (A) Five-six lamellae; (B) three lamellae (C) unilamellar 3.1.Statistical data: Responses of different batches obtained using box benhken design are shown in Table 3 obtained data were subjected to multiple regression analysis using Design Expert (Version ; Stat-Ease Inc, Minneapolis, Minnesota). Y = b 0 + b 1 X 1 + b 2 X 2 + b 3 X 3 + b 12 X 1 X 2 + b 13 X 1 X 3 + b 23 X 2 X 3 + b 11 X b 22 X b 33 X 3 2 Table 3: Responses obtained for studied parameters from experimental batches (n=3) Formulation Mean Particle size Polydispersity Index %Entrapment %CDR code (nm) Efficiency F ± ± ± ±2.5 F ± ± ± ±3.1 F ± ± ± ±2.8 F ± ± ± ±1.9 F ± ± ± ±1.4 F ± ± ± ±2.2 F ± ± ± ±2.6 F ± ± ± ±1.3 F ± ± ± ±2.5 F ± ± ± ±1.7 F ± ± ± ±2.1 F ± ± ± ±3.5 F ± ± ± ±1.7 F ± ± ± ±2.1 F ± ± ± ±1.1 Volume 1(2) March-April 2013 Page 183

%CDR %CDR %CDR 100 Diffusion study of Liposomal Suspension at 7.4 ph 100 Diffusion study of Liposomal Suspension at 7.

4 ph 0 F14 0 2 4 6Time(hr) 8 10 12 F15 14 Figure 3: %cumulative release of drug content of all formulation batches F1-F15 Table 4: Summary of regression analysis results for measured responses

5 %CDR %CDR %CDR 100 Diffusion study of Liposomal Suspension at 7.4 ph 100 Diffusion study of Liposomal Suspension at 7.4 ph F1 F2 F3 F F Time(hr) F6 F7 F8 F9 F Time(hr) Diffusion study of Liposomal Suspension at 7.4 ph 0 F Time(hr) F15 14 Figure 3: %cumulative release of drug content of all formulation batches F1-F15 Table 4: Summary of regression analysis results for measured responses Parameters b 0 b 1 b 2 b 3 b 12 b 13 b 23 b 11 b 22 b 33 Mean Particle size %Entrapment Efficiency %CDR Effect of variables on particle size: The most important parameter, which needs to monitor during liposome preparation its best performance, is the vesicle size and size distribution of liposomes. F11 F12 F13 (a) (b) (c) Figure 4: Response surface plots of (a) Soya Lecithin (X 1 ) and DPPS (X 2 ), (b) Soya Lecithin (X 1 ) and Cholesterol(X 3 ) and (c) DPPS(X 2 ) and Cholesterol (X 3 ) on the Mean Particle/Vesicle Size. Volume 1(2) March-April 2013 Page 184

From the number of reports, it was observed that the size and size distribution of the liposome determines their in- vivo or ex-vivo performance.

Thus for the effective delivery, the selected method should result in optimum size range and homogeneous population.

400 indicates obtained liposome population have narrow size distribution (Table 3).

$deposition. EE is expressed as the fraction of drug incorporated into liposomes relative to total amount of drug used.$ In the present study, the observed EE for all batches were in the range of 60 80%. A positive correlation was observed for both variables X 1, X 2 and X 3.

In the present study, the observed EE for all batches were in the range of 60 80%. A positive correlation was observed for both variables X 1, X 2 and X 3.

Among all the batches, which had minimum vesicle size and intermediate EE%, selected for the further study of gel formulation.

(a) (b) (c) Figure 5: Response surface plots of (a) Soya Lecithin (X 1 ) and DPPS (X 2 ), (b) Soya Lecithin (X 1 ) and Cholesterol(X 3 ) and (c) DPPS(X 2 ) and

6 From the number of reports, it was observed that the size and size distribution of the liposome determines their in- vivo or ex-vivo performance. There are some reports, which showed the effect of liposome size on the drug release as well as drug deposition in the skin. Thus for the effective delivery, the selected method should result in optimum size range and homogeneous population. In the present study, film hydration technique found to produce polydispersity index of less than indicates obtained liposome population have narrow size distribution (Table 3). It was observed that the relative amount of DPPS, Soya Lecithin and Cholesterol was found to play important role in vesicle size (Fig.4) Effect of variables on entrapment efficiency: Determination of EE is an important parameter in case of liposomes as it may affect the drug release and skin deposition. EE is expressed as the fraction of drug incorporated into liposomes relative to total amount of drug used. In the present study, the observed EE for all batches were in the range of 60 80%. A positive correlation was observed for both variables X 1, X 2 and X 3. Thus with increase in the concentration of Soya Lecithin, DPPS and Cholesterol entrapment efficiency found to be increased (Fig. 5). Among all the batches, which had minimum vesicle size and intermediate EE%, selected for the further study of gel formulation. Small particle size liposomes can cover the skin surface more compared to larger particle size. (a) (b) (c) Figure 5: Response surface plots of (a) Soya Lecithin (X 1 ) and DPPS (X 2 ), (b) Soya Lecithin (X 1 ) and Cholesterol(X 3 ) and (c) DPPS(X 2 ) and Cholesterol (X 3 ) on the %Entrapment Efficiency Effect of variables on %Cumulative Drug Release: In-vitro permeation profile of the Prednisolone from the different liposomal suspension formulations in 7.4 ph phosphate buffer was studied. In vitro permeation of Prednisolone from the liposomal formulation was found to be in the range of 70-97% during a period of 12 h. Thus, the liposomal formulations release the drug for prolonged period. (a) (b) (c) Figure 6: Response surface plots of (a) Soya Lecithin (X 1 ) and DPPS (X 2 ), (b) Soya Lecithin (X 1 ) and Cholesterol(X 3 ) and (c) DPPS(X 2 ) and Cholesterol (X 3 ) on the %CDR. Volume 1(2) March-April 2013 Page 185

7 Y 3 = X X X X 1 X X 1 X X 2 X X X X Characterization of liposomal gel Physical examination, ph, Viscosity, Content uniformity of gel: All liposomal gel formulations were found to be clear and transparent. The ph of the liposomal gel was found to be in the range of 6-7.The range of content uniformity was from 89.75% to 99.44%. All the formulations were found to be Clear and transparent Skin permeation and drug deposition studies: Results obtained from in-vitro drug permeation studies conducted with different formulations of prednisolone are shown in Significant augmentation in the skin permeation of prednisolone has been observed. Table 5: Result of all the carbopol 940P formulations (Batch F14) Formulation code ph % Content uniformity Viscosity (cps) %Cumulative drug Release CF14 (1%) 6.97± ± ± ±1.34 CF 14 (1.5%) 6.85± ± ± ±1.53 CF 14 (2%) 7.16± ± ± ± Stability Studies: Stability of liposome dispersion as well as 2% w/w carbopol liposomal gel containg equivalent 10mg prednisolone was carried out for 60 months at 4-8 C and room temperature. Responses obtained for different parameters for liposomal dispersion and liposomal gel during stability period are as shown in Table 5. Liposomes were found to be reasonably stable in terms of aggregation, fusion and/or vesicle disruption tendencies, over the studied storage period. From results it can be concluded that at room temperature and freeze temperature there was slightly but insignificantly decrease in % entrapment efficiency and increase in particle size for liposomal batch. Deposition of prednisolone in rat skin from liposomal gel was found insignificantly decreased during stability period. Result suggests that keeping the liposomal product in refrigeration conditions minimizes stability problems of liposomes. Table 6: Effect on Mean Particle/vesicle size, entrapment efficiency and drug deposition from liposomal gel during stability No. Of Mean Particle size %Entrapment Efficiency %CDR days 4-8ºC RT 4-8ºC RT 4-8ºC RT ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± DISCUSSION Preparation of liposomes using statastical design was found to be well suited and sound approach to obtain stable liposomal formulation. Variables such as amount of phospholipids have a profound effect on the vesicle size and entrapment efficiency. Rheological studies of all liposomal gels prepared with 1%, 1.5%, and 2% w/w carbopol gave a clear idea of concentration of carbopol required i.e. 2 % carbopol 940P. Liposomal dispersion and gels were found to increase the skin permeation and deposition compared to control. Stability studies performed for liposomal dispersion and Liposomal gel indicates the prepared liposomes have more stability at freezing temperature than that of room temperature. Prednisolone molecules could be successfully entrapped in liposomes with reasonable drug loading. Hence from results obtained it can be concluded that liposomal gel containg Prednisolone has potential application in topical delivery. 6. ACKNOWLEDGEMENT Athors are thankful to Mercury Laboratories Pvt. Ltd, Vadodara; Lipoid LMBH, Germany and Novastell, France for providing Prednisolone gift sample and Phospholipid respectively and Dr. Reddy, Hyderabad for kind help in characterisation. Volume 1(2) March-April 2013 Page 186

8 REFERENCES Brahmankar DM, Jaiswal SB. Biopharmaceutics and pharmacokinetics: A treatise; 1 st prakashan, 2007, 335. Edn; Vallabh Guo J, Ping Q, Sun G, Lecithin vesicular carriers for transdermal delivery of cyclosporine, Int J Pharm, 2000, 194, Jain NK. Advances in controlled and novel drug delivery; 1 st Edn; CBS Publication and distributors, New Delhi, 2005, 309. Jain S, Jain P, Umamaheshwari RB, Transfersomes a novel vesicular carrier for enhanced transdermal delivery: development, characterization, and performance evaluation, Drug Dev Ind Pharm, 2003, 29, Kim MK, Chung SJ, Lee MH, Delivery of hydrocortisone from liposomal suspensions to the hairless mouse skin following topical application under non-occlusive and occlusive conditions, J Microencapsul, 1998, 15, Kokare CR, Mitkari BV, Korde SA, Mahadik KR, Formulation and evaluation of topical liposomal gel for Fluconazole, Int J. Pharm. Educ. Res, 2010, 44, Korting HC, Schmid MH, A review-therapeutic progress with topical liposome drugs for skin Disease, Advanced Drug Delivery Reviews, 1996, 18, Kurakula M, Srinivas C, Kasturi N, Diwan PV, Formulation and Evaluation of Prednisolone Proliposomal gel for effective Topical Pharmacotherapy, Inter J Pharm Sci & Drug Research, 2012, 4, Mishra D, Garg M, Dubey V, Elastic liposomes mediated transdermal delivery of an anti-hypertensive agent: propranolol hydrochloride, J Pharm Sci, 2007, 96, Pokharkar VB, Padamwar MN, Development of vitamin loaded topical liposomal formulation using factorial design approach: Drug deposition and stability, Int J Pharm, 2006, 320, Seth AK, Misra A, Umrigar D, Topical liposomal gel of idoxuridine for the treatment of herpes simplex: pharmaceutical and clinical implications, Pharm Dev Technol, 2004, 9, The United State Pharmacopoeia, 28 (USP NF), The Official Compendia of Standards, Asian Edition, 2006, Vyas SP, Khar RK. Targeted & Controlled Drug Delivery; CBS Publication, Delhi, 2002, 173. Yamada S, Hanato J, Kuriyama K, Liposomal formulations of glucagon-like peptide-1: Improved bioavailability and anti-diabetic effect. Int J Pharm, 2009, 382, Volume 1(2) March-April 2013 Page 187

Formulation and Evaluation of Acyclovir Liposomes

Krishna Mohan Chinnala and Rabinarayan Panigrahy., 217/ Formulation and evaluation of acyclovir RESEARCH ARTICLE International Research Journal of Pharmaceutical and Biosciences Pri -ISSN: 2394-5826 http://www.irjpbs.com