HME-assisted formulation of taste-masked dispersible tablets of cefpodoxime proxetil and roxithromycin.

Objectives: Antibiotics are the most commonly administered medications among pediatric patients. However most of the time, accurate dose administration to children becomes a problem due to the extremely bitter taste. Cefpodoxime proxetil (CP) and roxithromycin (ROX) are antibiotics often prescribed to the pediatric population and have a bitter taste. Marketed formulations of these drugs are dry suspension and/or tablets. The lyophilization method involves various steps and thus is time consuming and expensive. The objective of this study was to mask the bitter taste of CP and ROX without compromising the solubility and drug release profile compared to marketed formulations, as well as to overcome the disadvantages associated with the currently used lyophilization technique. Methods: Hot melt extrusion (HME) technology was used to process CP and ROX individually with Eudragit E PO polymer. The extrudates obtained were characterized by Fourier transform infrared spectroscopy, powder X-ray diffraction, and differential scanning calorimetry. The powdered extrudates were formulated as dispersible tablets and evaluated for in vitro and in vivo taste-masking efficiency. Results: The tablets prepared in this study showed comparable dissolution profiles but the taste-masking efficiency was significantly enhanced compared to the marketed tablets of CP and ROX. The results of in vivo human taste-masking evaluation were also in agreement with the in vitro taste-masking studies. Conclusion: The current work presents solvent-free, scalable, and continuous HME technology for addressing the bitter taste issues of CP and ROX. The disadvantages associated with the currently used lyophilization technique were overcome by developing the formulations using HME technology.

An overview of regulations for bioequivalence assessment of locally acting orally inhaled drug products for the United States, Europe, Canada, and India.

INTRODUCTION: Bioequivalence is established by comparing the bioequivalence study results of generic drugs with the reference listed drug. Several global regulatory agencies have published the guidance for locally acting orally inhaled drug products (OIDPs) for bioequivalence approaches. AREAS COVERED: The prime intent of the present article is to compare the regulatory guidance for bioequivalence assessment of locally acting OIDPs published by global regulatory authorities. Regulatory recommendations on bioequivalence were based on assessment for different parameters such as inhaler device, formulation, reference product selection, in-vitro, and in-vivo studies. The United States Food and Drug Administration and Health Canada suggest an aggregated weight of evidence approach and the European Medicines Agency promotes a stepwise approach, whereas though the Indian authorities have not published guidance specifically on OIDPs but provided guidelines for bioavailability and bioequivalence studies. EXPERT OPINION: For OIDPs, currently, there is no universally adopted methodology, and regulatory guidance has not been globally harmonized. By understanding and comparing bioequivalence recommendations for different regions, we can create more sensitive, and economic evaluation methods for OIDPs. This could open more alternatives of safe, effective generic OIDPs to the public.

Investigation of 1,2-Dimyristoyl-sn-Glycero-3-Phosphoglycerol-Sodium (DMPG-Na) Lipid with Various Metal Cations in Nanocochleate Preformulation: Application for Andrographolide Oral Delivery in Cancer Therapy.

This study aimed at carrying out a preformulation investigation of nanocochleates (NCs) and develop andrographolide-loaded nanocochleates. Preformulation study comprised of exploring the effect of trivalent and divalent ions on transition temperature (TT) of lipid (DMPG-Na), on particle size (PS), entrapment efficacy (EE), zeta potential (ZP) of NCs, and effect of NCs on change in lipid solubility post-NC formation. Further, the andrographolide-loaded nanocochleates made with CaCl2 (ANDNCs) were characterized for ZP, PS, EE, X-ray powder diffraction (PXRD), differential scanning calorimetry (DSC), transition electron microscopy (TEM), in vitro release studies, in vitro anticancer potential on the cell line of human breast cancer (MCF-7), in vivo oral pharmacokinetic studies, and tissue distribution in female Wistar rats. Nanocochleates developed with CaCl2 had a significant reduction in PS (1.78-fold) and ZP (1.38-fold), and elevation of EE (1.17-fold) as compared to AlCl3 developed NCs. Trivalent ions demonstrated elevation of TT as compared to divalent ions. Spiral-shaped ANDNCs demonstrated ZP, PS, and EE of - 121.46 ± 15.12 mV, 360 ± 47 nm, and 68.12 ± 3.81% respectively. In vitro release study of ANDNCs showed a strong pH-dependent release profile due to hydrogen bonding between NCs and andrographolide (AND). Formulated ANDNCs demonstrated 26.99-fold decrease in IC50 value as compared to free AND. Additionally, the oral bioavailability of AND from ANDNCs improved by 1.81-fold as compared to free AND. Furthermore, ANDNCs showed minimum accumulation within the vital organs such as liver, kidney, and spleen. Briefly, the preformulation study laid a platform for better understanding the NCs and its components. Further, developed ANDNCs revealed superior physiochemical properties to be used as an alternative for a clinical setting.

Development of High-Strength Extended-Release Multiparticulate System by Crystallo-co-agglomeration Technique with Integration of Central Composite Design.

The number of unit operations to be followed in the preparation of tablets was cumbersome and may introduce material as well as process-related critical parameters which may negatively affect the quality of final formulation. The hypothesis of the present research was to develop directly compressible, high-strength extended-release spherical agglomerates of talc containing indapamide by crystallo-co-agglomeration technique. Hydroxypropyl methylcellulose 15 cps and polyethylene glycol 6000 were used to impart the desired sphericity, strength, and deformability to agglomerates, respectively. Ethyl cellulose 10 cps was used to improve the strength of agglomerates and achieve extended release. Design of experiment (rotatable central composite design) was implemented for the elucidation of the effect of type and quantity of polymers on quality attributes of agglomerates. Prepared agglomerates were evaluated for morphological, micromeritic, mechanical, and drug release properties. A satisfactory yield (> 97%, wt/wt), better crushing strength, and low friability of agglomerates indicated good processing and handling characteristics. Compatibility and reduced crystallinity of indapamide in agglomerates were confirmed by spectroscopic and X-ray diffraction studies. Formation of the miniscular dosage form and hydrophobicity of talc were the key factors observed in controlling and extending the drug release (up to 6 h) from agglomerates. Hence, the developed crystallo-co-agglomeration technique could be successfully used for the preparation of directly compressible high-strength extended-release spherical agglomerates of indapamide.

Formulation and evaluation of optimized oxybenzone microsponge gel for topical delivery.

Background. Oxybenzone, a broad spectrum sunscreen agent widely used in the form of lotion and cream, has been reported to cause skin irritation, dermatitis, and systemic absorption. Aim. The objective of the present study was to formulate oxybenzone loaded microsponge gel for enhanced sun protection factor with reduced toxicity. Material and Method. Microsponge for topical delivery of oxybenzone was successfully prepared by quasiemulsion solvent diffusion method. The effects of ethyl cellulose and dichloromethane were optimized by the 3(2) factorial design. The optimized microsponges were dispersed into the hydrogel and further evaluated. Results. The microsponges were spherical with pore size in the range of 0.10-0.22 µm. The optimized formulation possesses the particle size and entrapment efficiency of 72 ± 0.77 µm and 96.9 ± 0.52%, respectively. The microsponge gel showed the controlled release and was nonirritant to the rat skin. In creep recovery test it had shown highest recovery indicating elasticity. The controlled release of oxybenzone from microsponge and barrier effect of gel result in prolonged retention of oxybenzone with reduced permeation activity. Conclusion. Evaluation study revealed remarkable and enhanced topical retention of oxybenzone for prolonged period of time. It also showed the enhanced sun protection factor compared to the marketed preparation with reduced irritation and toxicity.

Investigation of ethyl cellulose microsponge gel for topical delivery of eberconazole nitrate for fungal therapy.

BACKGROUND: The aim of the study was to investigate ethyl cellulose microsponges as topical carriers for the controlled release and cutaneous drug deposition of eberconazole nitrate (EB). MATERIALS & METHOD: EB microsponges were prepared using the quasiemulsion solvent diffusion method. The effect of formulation variables (drug:polymer ratio, internal phase volume and amount of emulsifier) and process variables (stirring time and stirring speed) on the physical characteristics of microsponges were investigated. The optimized microsponges were dispersed into a hydrogel and evaluated. RESULTS & DISCUSSION: Spherical and porous EB microsponge particles were obtained. The optimized microsponges possessed particle size, drug content and entrapment efficiency of 24.5 µm, 43.31% and 91.44%, respectively. Microsponge-loaded gels demonstrated controlled release, nonirritancy to rat skin and antifungal activity. An in vivo skin deposition study demonstrated fourfold higher retention in the stratum corneum layer as compared with commercial cream. CONCLUSION: Developed ethyl cellulose microsponges could be potential pharmaceutical topical carriers of EB in antifungal therapy.

Development of Budesonide Loaded Biopolymer Based Dry Powder Inhaler: Optimization, In Vitro Deposition, and Cytotoxicity Study.

The progress in the development of DPI technology has boosted the use of sensitive drug molecules for lung diseases. However, delivery of these molecules from conventional DPI to the active site still poses a challenge with respect to deposition efficiency in the lung. At same time, serious systemic side effects of drugs have become a cause for concern. The developed budesonide loaded biopolymer based controlled release DPI had shown maximum in vitro lung deposition with least toxicity. The subject of present study, lactose-free budesonide loaded biopolymer based DPI, further corroborates the great potential of antiasthmatic drugs. This technology is expected to revolutionize the approaches towards enhanced therapeutic delivery of prospective drugs.

Fisetin-loaded nanocochleates: formulation, characterisation, in vitro anticancer testing, bioavailability and biodistribution study.

BACKGROUND: The natural flavonoid fisetin has shown anticancer properties but its in vivo administration remains challenging due its poor aqueous solubility and extensive in vivo metabolism. This juncture demands an effective, controlled release and safe formulation of fisetin would be a significant advance for the treatment of cancer. OBJECTIVES: Nanocochleates are unique lipid-based supramolecular assemblies composed of a negatively charged phospholipid and a divalent cation. The aim was to develop and evaluate fisetin-loaded nanocochleates to improve its therapeutic efficacy. Using the trapping method, fisetin-loaded dimyristoylphosphatidylcholine liposomal vesicles were converted into nanocochleates by the action of Ca(2+) ions. These nanocochleates were further evaluated for physicochemical, in vitro anticancer and haemolysis, pharmacokinetics and tissue distribution study in mice. RESULTS: Stable rolled-up layers as well as elongated structure of nanocochleates possessing particle size and encapsulation efficiency (EE) of 275 + 4 nm and 84.31 ± 2.52%, respectively were obtained. Nanocochleates demonstrated safety and a sustained release of fisetin at physiological pH. A 1.3-fold improvement in vitro anticancer towards human breast cancer MCF-7 cells was observed. Pharmacokinetics studies in mice revealed that nanocochleates injected intraperitonially showed a 141-fold higher relative bioavailability. Moreover, a low tissue distribution was observed. CONCLUSION: Developed nanocochleates markedly improved anticancer efficacy, bioavailability and safety of fisetin. The nanocochleates technology would facilitate the administration of this flavonoid in the clinical setting. AREAS COVERED: In this research article, we focused on lipid-based supramolecular assembly 'nanocochleates' composed of negatively charged phospholipids and divalent cation as drug carrier for systemic delivery system and discussed their formulations, optimisation, characterization, in vitro and in vivo performance.

Development of plumbagin-loaded phospholipid-Tween® 80 mixed micelles: formulation, optimization, effect on breast cancer cells and human blood/serum compatibility testing.

BACKGROUND: Phospholipid and Tween(®) 80 mixed micelles were investigated as injectable nanocarriers for the natural anticancer compound, plumbagin (PBG), with the aim to improve anticancer efficiency. PBG-loaded mixed micelles were fabricated by self-assembly; composition being optimized using 3(2) factorial design. RESULTS & DISCUSSION: Optimized mixed micelles were spherical and 46 nm in size. Zeta potential, drug loading and encapsulation efficiency were 5.04 mV, 91.21 and 98.38% respectively. Micelles demonstrated sustained release of PBG. Micelles caused a 2.1-fold enhancement in vitro antitumor activity of PBG towards MCF-7 cells. Micelles proved safe for intravenous injection as PBG was stable at high pH; micelle size and encapsulation efficiency were retained upon dilution. CONCLUSION: Developed mixed micelles proved potential nanocarriers for PBG in cancer chemotherapy.

Novel solvent-free gelucire extract of Plumbago zeylanica using non-everted rat intestinal sac method for improved therapeutic efficacy of plumbagin.

INTRODUCTION: Various shortcomings of the available methods of extraction of plumbagin from Plumbago zeylanica using non-edible organic solvents coupled with the poor aqueous solubility and low bioavailability called for extracting plumbagin in a water soluble form via a single step technique using hydrophilic lipid Gelucire 44/14. METHODS: Gelucire extract of P. zeylanica (GPZ) was prepared and evaluated for extraction efficiency, High-performance thin layer chromatography (HPTLC) and thermal analysis. In vitro intestinal absorption and bioavailability of plumbagin from GPZ in comparison with that of aqueous (APZ), ethanolic extract (EPZ) and standard plumbagin studied using non-everted rat intestinal sac model. RESULTS: The GPZ showed significantly higher extraction efficiency (3.24±0.12% w/w) compared to ethanolic (EPZ) and aqueous (APZ) extraction, 2.48±0.16% w/w and 0.07±0.02% w/w respectively. GPZ displayed significantly higher Q(30min) (cumulative percentage absorption of plumbagin in 30 min) and lower t(40%) (time required for 40% w/w drug absorption). The flux and apparent permeability coefficient in duodenum and ileum were 2, 3 and 6 fold higher than EPZ, standard plumbagin and APZ respectively. DISCUSSION: Improved therapeutic efficacy of plumbagin may be due to the micellar solubilization and consequent enhanced partitioning of plumbagin through intestinal by Gelucire which was reflected in the in vivo anti-inflammatory study conducted in rats. CONCLUSION: Thus extraction using Gelucire can be proclaimed as an efficient, economic and solvent-free technique for extraction of plumbagin and can be utilized for various clinically important water insoluble phytoconstituents in order to improve their biopharmaceutical properties.

Development of photostable gastro retentive formulation for nifedipine using low-density polypropylene microporous particles.

The aim of this study was to develop photostable gastro retentive formulation for nifedipine loading into low-density polypropylene microporous particles (Accurel MP 1000®) by a solvent evaporation technique using the 3² factorial design. Yield, drug loading, surface topography, thermal properties, crystal characteristics, photostability and in vitro drug release were studied. Optimized microparticles formulated into a capsule were evaluated for the dissolution study and compared with marketed formulation. Higher values of T(50%), time required for 50% degradation of drug with threefold and 1.5-fold decrease in degradation rate constant (K) under UV and fluorescent lamp were observed for the microparticles, respectively, as compared to pure nifedipine indicated remarkable improved photostability. Microparticles showed good floating ability in 0.1N HCl with initial burst release (16-29%) followed by the zero-order drug release up to 8 h. The capsule formulation followed the ideal modified release pattern.

Preparation and evaluation of talc agglomerates obtained by wet spherical agglomeration as a substrate for coating.

The present research was aimed at the preparation of spherical agglomerates of talc (SAT) by wet spherical agglomeration (WSA) and evaluation as inert core/substrate for coating. Talc being an inert and inexpensive excipient was used in the design of spherical agglomerates. To evaluate agglomerate performance, comparison was made with sugar spheres (SS), having a size 1200 µm, for surface morphology, micromeritics, mechanical, compressional and drug release properties. Surface morphology studied by scanning electron microscopy (SEM) and optical profilometry have shown smooth surface of SAT compared to SS. Shape and sphericity analysis of both showed aspect ratio close to 1. Flowability of SAT was similar to SS. Although, crushing force of SAT was significantly less than SS (p = 0.05), friability studies revealed that it was satisfactory. Compressibility studies showed plastic deformation of SAT unlike SS. Both SAT and SS had comparable drug and polymer layering efficiency, with better surface smoothness in SAT than SS, as confirmed from optical profilometry. Thus, SAT, similar to SS, can be used as a substrate for coating due to its comparable surface topography, micromeritics, adequate crushing resistance and satisfactory drug and polymer layering efficiency.

Novel/conceptual floating pulsatile system using high internal phase emulsion based porous material intended for chronotherapy.

The aim of the present study was to design a novel/conceptual delivery system using ibuprofen, anticipated for chronotherapy in arthritis with porous material to overcome the formulation limits (multiple steps, polymers, excipients) and to optimize drug loading for a desired release profile suitable for in vitro investigations. The objective of this delivery system lies in the availability of maximum drug amount for absorption in the wee hours as recommended. Drug loading using 3(2) factorial design on porous carrier, synthesized by high internal phase emulsion technique using styrene and divinylbenzene, was done via solvent evaporation using methanol and dichloromethane. The system was evaluated in vitro for drug loading, encapsulation efficiency, and surface characterization by scanning electron, atomic force microscopy, and customized drug release study. This study examined critical parameters such as solvent volume, drug amount, and solvent polarity on investigations related to drug adsorption and release mostly favoring low-polarity solvent dichloromethane. Overall release in all batches ranged 0.98-52% in acidic medium and 71-94% in basic medium. These results exhibit uniqueness in achieving the least drug release of 0.98%, an ideal one, without using any release modifiers, making it distinct from other approaches/technologies for time and controlled release and for chronotherapy.

Evaluation of molecular pharmaceutical and in-vivo properties of spray-dried isolated andrographolide-PVP.

OBJECTIVES: Andrographolide, a natural lipophilic molecule, has a wide range of pharmacological actions. However, due to low aqueous solubility, it has low oral bioavailability. The purpose of the study was to increase the solubility and dissolution rate of isolated andrographolide by formulating its solid dispersion. METHOD: Solid dispersions were obtained by a spray-drying technique using different ratios of drug to polyvinylpyrrolidine (PVP K-30). Solid dispersions in compression with isolated drug and corresponding physical mixtures were characterized for various molecular pharmaceutical properties and subjected to stability study for up to 3 months. KEY FINDINGS: A five-fold increase in saturation solubility of andrographolide with higher values of Q(5 min) (cumulative percentage release in 5 min) and lower values of t(75%) (time required for 75% w/w drug release) for solid dispersion was observed in different dissolution mediums. This was attributed to the formation of amorphous nature and intermolecular hydrogen bonding between drug and PVP K-30. The stability study showed there to be no significant change in molecular pharmaceutical properties and dissolution profile over the period of 3 months. Moreover, the in-vivo study in Wistar albino rats also justified improvement in the therapeutic efficacy of andrographolide after solid dispersion. CONCLUSIONS: This study demonstrates the utility of solid dispersion to improve primary and secondary pharmaceutical properties of andrographolide using PVP K-30 as a carrier.

Modulation and optimization of drug release from uncoated low density porous carrier based delivery system.

The purpose of this research work was to explore an application of uncoated porous drug carrier prepared by single-step drug adsorption for a delivery system based on integration of floating and pulsatile principles intended for chronotherapy. This objective was achieved by utilizing 3(2) factorial design, solvent volume (X(1)) and drug amount (X(2)) as selected variables, for drug adsorption using solvents, methanol, and dichloromethane (DCM), of varying polarity. Nitrogen adsorption (N(2)), scanning electron microscopy of cross-sections, and atomic force microscopy were done to study adsorption patterns and their effect on release pattern. Drug release study was customized by performing for 6 h in acidic environment to mimic gastroretention followed by basic environment akin to transit phase. Correlation between porous data from mercury and N(2) adsorption was probably studied for the first time. Observed regression analysis values for pore volume, surface area, and drug release indicated the influence of selected variables. Total release range in acidic medium was 12.77-24.57% for methanol, 8.79-15.26% for DCM, and final release of 69.45-92.23% for methanol, and 60.16-99.99% for DCM influenced by varying internal geometries was observed. Present form of drug delivery system devoid of any additives/excipients influencing drug release shows distinct behavior from other approaches/technologies in chronotherapy by (a) observing desired low drug release (8%) in acidic medium, (b) overcoming the limitations of process variables caused by multiple formulation steps and different characteristic polymers, (c) reducing time consumption due to single step process, and (d) extending as controlled/extended release.

Effect of core and surface cross-linking on the entrapment of metronidazole in pectin beads.

The purpose of this study was to improve the entrapment efficiency of the water-soluble drug metronidazole using internal cross-linking agents. Calcium pectinate beads containing metronidazole were prepared by dropping a drug-pectin solution in 1% and 5% (m/V) calcium chloride for surface cross-linked beads. For the core cross-linked beads calcium carbonate was dispersed in the drug-pectin solution. The beads were characterized by particle size, swelling ratio, SEM, DSC, and in vitro drug release. It was found that the beads obtained by core cross-linking produced more drug entrapped beads than the surface cross-linked beads. Beads obtained using 1% (m/V) calcium chloride showed more drug entrapment than these obtained using 5% calcium chloride. The core cross-linking of pectin beads reduced drug loss by about 10-20%. The water lodging capacity of beads depended upon gel strength which is a function of the internal gelling agent and pectin concentration. Complete drug release was observed within 30-60 min in the acidic dissolution medium. This work has showed that the core cross-linking agent increases the water-soluble drug entrapment in calcium pectinate beads.

Low density porous carrier drug adsorption and release study by response surface methodology using different solvents.

Low density porous carriers are widely used in the pharmaceutical applications. Response surface methodology, using 3(2) factorial design was used to study drug adsorption on and its release patterns from microporous polypropylene (Accurel MP 1000) in the absence of additives. Ibuprofen, as model drug, was adsorbed on the polymer by solvent evaporation using two organic solvents methanol (M) and dichloromethane (DCM). The amount of carrier (100 mg) and its particle size range (250-350 microm) were kept invariant while solvent volume (X1) and drug amount (X2) were taken as variables. Drug adsorption pattern depended on the type and amount of solvent used. DSC, XRD, FTIR and TGA, predict crystalline nature and physical form of adsorption. SEM showed the penetration and adsorption of the drug in and on the microporous polymer. Accurel MP 1000 had a pore volume of 1.992 g/cm3 and surface area of 55.9855 m2/g as detected by mercury porosimetery. On drug adsorption, pore volume ranged from 0.413 to 1.198 g/cm3 for methanol and 0.280-0.759 g/cm3 for DCM. Similarly surface area was in the range 38.445-25.497 m2/g for methanol and 18.710-32.528m2/g for DCM. The drug release was investigated in phosphate buffer pH 7.2. All batches showed excellent in vitro floating property. Drug release was partial with recovery to complete dependent on type and volume of solvent. R2 values relating to bulk density, pore volume, surface area and drug release at 60, 120 and 180 min were estimated. Effect of solvent properties shows a positive influence on drug adsorption and release. Release profiles of some batches could be considered as gastroretentive drug delivery system.

Development of hollow/porous calcium pectinate beads for floating-pulsatile drug delivery.

The purpose of this work was to develop hollow calcium pectinate beads for floating-pulsatile release of diclofenac sodium intended for chronopharmacotherapy. Floating pulsatile concept was applied to increase the gastric residence of the dosage form having lag phase followed by a burst release. To overcome limitations of various approaches for imparting buoyancy, hollow/porous beads were prepared by simple process of acid-base reaction during ionotropic crosslinking. The floating beads obtained were porous (34% porosity), hollow with bulk density<1 and had Ft50% of 14-24 h. In vivo studies by gamma scintigraphy determined on rabbits showed gastroretention of beads up to 5 h. The floating beads provided expected two-phase release pattern with initial lag time during floating in acidic medium followed by rapid pulse release in phosphate buffer. This approach suggested the use of hollow calcium pectinate microparticles as promising floating-pulsatile drug delivery system for site- and time-specific release of drugs acting as per chronotherapy of diseases.

The effect of drug concentration and curing time on processing and properties of calcium alginate beads containing metronidazole by response surface methodology.

The purpose of present research work was to prepare calcium alginate beads containing water-soluble drug metronidazole using 3(2) factorial design, with drug concentration and curing time as variables. Curing time was kept as low as possible to improve entrapment with increasing drug concentration. Mostly the drugs which had been encapsulated were water insoluble to facilitate drug encapsulation; a characteristic drug release as whole process is aqueous based. Entrapment efficiency was in the range of 81% to 96% wt/wt, which decreased with decrease in polymer concentration and increase in curing time. The beads were spherical with size range between 1.4 and 1.9 mm. Scanning electron microscope (SEM) photomicrographs revealed increase in the leaching of drug crystals with increased curing time and high drug concentrations. In acidic environment, the swelling ratio was 200% in 30 minutes, but in basic medium, it increased to a maximum of 1400% within 120 minutes. In acidic medium, the swelling and drug release properties were influenced by drug solubility, whereas in phosphate buffer these properties were governed by the gelling of polymer and exhibited curvilinear and quadratic functions of both the variables, respectively.

Silk sericin as a moisturizer: an in vivo study.

BACKGROUND: Excessive transepidermal water loss (TEWL) is the one of the causes of dry skin, and skin moisturizers have been used to overcome it. AIM: The purpose of this research was to study the moisturizing effect of sericin, a silk protein. Because silk sericin has resemblance with the natural moisturizing factor (NMF), it has been studied for its application in skin cosmetics. METHODS: Sericin gels were prepared using sericin solution and with pluronic and carbopol as stabilizers. The gels were applied on the skin of healthy human volunteers and its moisturizing efficiency was evaluated by measuring the skin hydroxyproline content, impedance, TEWL, and scanning electron microscopy (SEM) results. RESULTS: Decrease in skin impedance, increase in hydroxyproline level, and hydration of epidermal cells revealed the moisturizing effect of sericin, whereas decrease in the value of TEWL may be attributed to occlusive effect, which prevents water loss from the upper layer of the skin. Skin surface topography revealed the smoothness of the upper layer of the skin as a result of moisturization. CONCLUSION: Increase in the intrinsic moisturization of skin by sericin may be attributed to restoration of the amino acids and its occlusive effect. Thus, it would become a promising and important moisturizing ingredient in moisturizing formulations.