不同密度滚轮微针对曲安奈德的透皮促渗作用

目的探讨不同密度滚轮微针对曲安奈德经皮渗透的影响。方法采用改良Franz扩散池法考察体外经皮渗透特性,以离体裸鼠皮肤为屏障,对照组、192针、540针滚轮微针处理组分别于2、4、6、8、10、12h取接收液0．2ml,用HPLC法测定曲安奈德含量,计算累积渗透量,并测定皮肤内曲安奈德滞留量。采用测定血药浓度法考察在体吸收特性,在体给药2h后HPLC法测定各组皮肤及血浆中曲安奈德的含量。结果两种密度滚轮微针对曲安奈德均有不同程度的促透作用。离体透皮实验结果显示,192针微针处理组和540针微针处理组的累积渗透量Q分别是对照组的1．3倍和2．2倍,相应的皮肤内滞留量也分别是对照组的1．9倍和2．8倍。在体实验结果显示,192针微针和540针微针组的皮肤滞留量是对照组的2．1和2．3倍,同时也将血药浓度提高了1．3倍和1．4倍。结论结论两种不同密度滚轮微针均能有效提高曲安奈德的经皮渗透量,提高皮肤内药物含量,同时也导致血药浓度的增加,且不同密度微针的促透作用有所不同。     

不同密度滚轮微针对维A酸经皮渗透的影响

目的：探讨不同密度滚轮微针对维A酸经皮渗透的影响。方法：采用改良Franz扩散池法考察体外经皮渗透特性,以裸鼠离体皮肤为屏障,对照组、192针、540针滚轮微针处理组分别于2、4、6、8、10、12 h取接收液0.2 ml,用HPLC法测定维A酸含量,计算累积渗透量,并测定皮肤内维A酸滞留量。采用激光共聚焦显微镜考察在体经皮渗透特性,405 nm激发光波长下扫描,观察维A酸在皮肤内的渗透及分布。结果：离体实验中,HPLC法以平均峰面积（A）与对照品浓度（c）作线性回归,得标准曲线方程A=170 733 c-1 534.8（r=0.999 9）,线性范围为0.01~10.00 μg/ml,回收率均＞95%。192针、540针微针处理组的维A酸累积渗透量分别是对照组的2.5和6.8倍,相应的皮肤内滞留量分别是对照组的2.5和2.8倍。在体实验中,相同力度（350~400 g）下,使用192针、540针两种密度微针处理2 h后,两种微针组药物可渗透至皮肤深度分别是60和50 μm。结论：滚轮微针能有效提高维A酸的经皮渗透量,且不同密度微针的促透作用不同。     

基于药物-皮肤的相互作用探究盐酸特比萘芬体外透皮特性

目的 考察盐酸特比萘芬的体外透皮特性，探究盐酸特比萘芬与皮肤的相互作用，基于药物-皮肤相互作用阐明盐酸特比萘芬透皮特性的机制。方法 比较盐酸特比萘芬经皮渗透及其皮内滞留以及在皮肤各层的分布；利用衰减全反射红外光谱、差示扫描量热、拉曼光谱研究药物与皮肤的相互作用，并对药物与角质层角蛋白及脂质的相互作用进行计算机模拟和计算。结果 盐酸特比萘芬经皮渗透后高滞留低渗透，滞留的药物多分布于角质层。盐酸特比萘芬与角质层中脂质和角蛋白均有相互作用，该作用使药物自身难于透过皮肤，并导致较大的透过变异性。结论 盐酸特比萘芬与皮肤脂质和角蛋白的相互作用是其表现出典型的皮肤低渗透、高滞留特性的机制之一。本研究为盐酸特比萘芬体外透皮高滞留、低渗透特性提供理论依据。     

综合主成分分析法和皮肤电阻法对几种促透剂促透效果的比较

目的 建立一种简单有效的快速评价促透剂透皮吸收促进效果的方法，并比较综合主成分分析法和皮肤电阻法的促透剂评价结果。方法 以氨茶碱作为模型药物，氮酮、薄荷醇、冰片、油酸及其联用作为促透剂，SD大鼠背部离体皮肤作为渗透屏障，HPLC测定接收液中的药物浓度，计算累积渗透量、渗透系数、稳态流量、滞后时间和增渗倍数，运用综合主成分分析法对促透效果进行综合评价；测定在促透剂作用下的大鼠皮肤电阻随时间的变化，评价促透剂对皮肤的作用程度。结果 用Franz扩散池方法结合综合主成分分析法，得到对氨茶碱有促透效果的促透剂有油酸加冰片以及薄荷醇，且油酸加冰片的促透效果大于薄荷醇；用皮肤电阻法测得有促透作用的是油酸加冰片、薄荷醇加氮酮、薄荷醇、氮酮、油酸、冰片加氮酮以及薄荷醇加冰片，且作用程度依次递减。采用皮肤电阻法评价的促透效果与采用体外透皮吸收试验评价的结果基本平行(r=0.886 9)。结论 综合主成分分析法和皮肤电阻法都可以客观评价促透剂的效果，且2种方法具有明显的相关性。     

川丁特罗贴剂的设计及分子机制研究

目的 采用离子对与促透剂联合应用的促透策略，设计一种经皮透过性良好的川丁特罗贴剂，用于支气管哮喘的治疗。方法 首先采用有机溶媒挥散法制备川丁特罗经皮吸收贴剂，以Wistar大鼠皮肤为模型，采用单因素考察法在体外经皮透过试验中考察离子对与促透剂的联用对川丁特罗经皮透过行为的影响并优选贴剂处方。通过贴剂体外释放试验和红外光谱试验，探讨离子对及促透剂对川丁特罗经皮透过行为的影响及分子机制。结果 贴剂的优选处方为川丁特罗-对氨基苯甲酸为主药，载药量为5%，DURO-TAK^®87-4098为压敏胶基质，8%聚甘油油酸酯为促透剂。离子对的形成增加了川丁特罗的皮肤渗透性，而聚甘油油酸酯的加入对川丁特罗从贴剂中的释放和川丁特罗皮肤透过均有促进作用，2个技术的联用增加了川丁特罗的皮肤累积透过量。结论 本研究通过采用离子对与促透剂联合应用的策略，成功设计了川丁特罗压敏胶分散型贴剂，并从释放和经皮吸收2方面探讨了离子对和促透剂的作用机制，为开发川丁特罗贴剂提供参考。     

改装滚轮微针用于醋酸曲安奈德经皮给药的特性试验

目的:评价改装滚轮微针用于曲安奈德经皮给药的力度可控性、释药重现性和皮肤刺激性。方法:改装市售滚轮微针;石蜡切片、HE染色法观察不同微针使用力度(2.5,5.0,7.5,10.0,12.5,15.0,17.5,20.0 N)时的皮肤微孔深度,探讨改装前后其力度可控性;以离体裸鼠皮肤为屏障,Franz扩散池法考察改装前后曲安奈德经皮渗透特性;评分法测定皮肤刺激性。结果:皮肤微孔深度随微针使用力度的增加而加大,微孔深度范围由65.28~106.25 μm收窄为改装后的71.53~97.92 μm,其RSD范围由10.45%~19.69%显著下降至改装后的2.33%~9.21%。在相同微针使用力度下,曲安奈德的累积释药量RSD范围由改装前的34.75%~55.92%,显著下降至改装后的14.29%~29.73%。改装滚轮微针用药1 h时出现轻度皮肤刺激性,之后消失。结论:与市售滚轮微针相比,改装滚轮微针具有较好的力度可控性、释药重现性,以及较小的皮肤刺激性。     

滚轮微针技术对黄柏提取物乳膏中盐酸小檗碱经皮渗透的促进作用

采用回流法制备黄柏提取物,再制成o/w型乳膏.用HPLC法测定盐酸小檗碱的含量.以离体裸鼠皮肤为屏障,用改良Franz扩散池法考察乳膏中盐酸小檗碱的体外透皮性能,探讨滚轮微针技术对黄柏提取物乳膏中盐酸小檗碱体外经皮渗透行为和皮肤滞留量的影响.结果显示,不用或采用微针处理组乳膏中盐酸小檗碱12h的累积渗透量为(0.161±0.008)、(0.978±0.034) mg/cm2,经皮渗透速率为(0.035±0.007)、(0.197±0.018) mg·cm-2·h-1,皮肤滞留量为(0.373±0.021)、(1.364±0.342)mg/cm2.可见,滚轮微针技术能显著提高外用黄柏提取物乳膏中盐酸小檗碱的经皮渗透量(P＜0.05),增加皮肤内药物滞留量(P＜0.05).     

丹酚酸B-丹参酮ⅡA-甘草次酸微乳凝胶微针透皮给药的评价

目的 优化丹酚酸B （SalB）-丹参酮Ⅱ_A（TSNⅡ_A）-甘草次酸（GA）（STG）微乳凝胶的处方工艺,并考察微针给药对其促透和抗炎药效的影响。方法 以微乳凝胶的综合评分为响应值,选取卡波姆用量、微乳用量、pH值作为考察因素,通过Box-Behnken响应面法筛选最佳处方工艺。采用透皮扩散试验仪考察STG微乳凝胶、STG微乳凝胶+微针（长度分别为500、750、1 000μm）给药的体外经皮渗透特性,高效液相色谱（HPLC）测定TSNⅡ_A、Sal B和GA的含量。采用10%蛋清诱导小鼠足肿胀考察STG微乳凝胶（每次l g,每天2次,给药3 d）、STG微乳凝胶+微针（长度分别为500、750、1000μm）背部给药的抗炎作用,同时考察给药7d对小鼠皮脂腺斑组织的作用。结果 STG微乳凝胶的最佳制备工艺中卡波姆用量为1.00%、微乳用量为0.10 g、pH值为6,制备的STG微乳凝胶中含TSNⅡ_A、SalB、GA分别为0.18、1.05、1.53 mg·g^-1。与TSNⅡ_A比较,SalB和GA的透皮吸收较好;STG微乳凝胶经过与不同长度微针配合使用后的累积透皮量：STG微乳凝胶+1 000μm微针组>STG微乳凝胶+700μm微针组>STG微乳凝胶+500μm微针组>STG微乳凝胶组;3种药物在皮肤中的滞留量相对较高。与空白凝胶组比较,STG微乳凝胶组小鼠足肿胀度有所减轻,但无显著性差异;与STG微乳凝胶组比较,STG微乳凝胶+微针组小鼠足肿胀程度均明显减轻,以1 000μm微针组作用最显著（P<0.05、0.01）。小鼠皮脂腺斑组织HE染色结果表明,与空白凝胶组比较,各组小鼠皮脂腺数目减少且体积变小,以微针长度1 000μm组效果最显著。结论 STG微乳凝胶+微针给药具有良好的透皮特性和缓释效果,发挥抗炎及控制皮脂腺分泌作用,微针长度与透皮率的增加呈正相关。     

HPLC测定紫杉醇纳米脂质体凝胶剂在小鼠皮肤中的含量

目的 考察紫杉醇纳米脂质体凝胶剂给药4 h后在小鼠皮肤各层中的含量分布情况。方法 采用胶带粘贴技术剥脱角质层,以HPLC测定紫杉醇在皮肤各层中的含量,比较紫杉醇脂质体凝胶剂以及紫杉醇凝胶剂在皮肤各层中的分布特点。结果 紫杉醇纳米脂质体给药4 h后在角质层和活性皮肤层中的药物含量分别为3.41,5.35 μg·cm^-2,与紫杉醇凝胶剂比较,能显著提高药物在皮肤中的滞留量（P<0.05）。结论 与紫杉醇凝胶剂相比,紫杉醇纳米脂质体能增加药物的皮肤滞留量。     

促渗剂对后交联祖师麻凝胶贴膏体外经皮渗透影响的研究

目的 考察不同促渗剂对后交联祖师麻凝胶贴膏中药效成分祖师麻甲素体外经皮渗透特性的影响,筛选出其最佳的透皮促渗剂。方法 采用Franz扩散池法,以离体小鼠皮肤和Strat-M™膜为渗透屏障进行体外透皮试验,采用单因素及正交试验法,以祖师麻甲素72 h内单位面积的累积透过量为评价指标,考察冰片、薄荷脑、樟脑对祖师麻甲素的促渗效果。结果 以离体小鼠皮肤和Strat-M™人工膜为透皮屏障时,祖师麻甲素72 h内单位面积的累积透过量分别为33.85,15.96 μg·cm^-2,稳态透皮速率分别为4.451 2,2.394 5 μg·cm^-2·h^-1,增渗倍数分别可达4.255 0,1.746 4。结论 后交联祖师麻凝胶贴膏以1%薄荷脑、1%冰片、2%樟脑联用时促渗效果最佳。     

Characterization of Solid Maltose Microneedles and their Use for Transdermal Delivery

Purpose To characterize solid maltose microneedles and assess their ability to increase transdermal drug delivery. Materials and Methods Microneedles and microchannels were characterized using methylene blue staining and scanning electron microscopy. Diffusion pattern of calcein was observed using confocal scanning laser microscopy. Transepidermal water loss (TEWL) measurements were made to study the skin barrier recovery after treatment. Uniformity in calcein uptake by the pores was characterized and percutaneous penetration of nicardipine hydrochloride (NH) was studied in vitro and in vivo across hairless rat skin. Results Microneedles were measured to be 508.46 ± 9.32 μm long with a radius of curvature of 3 μm at the tip. They penetrated the skin while creating microchannels measuring about 55.42 ± 8.66 μm in diameter. Microchannels were visualized by methylene blue staining. Pretreatment with microneedles resulted in the migration of calcein into the microchannels. TEWL increased after pretreatment and uptake of calcein by the pores was uniform as measured by the pore permeability index values. NH in vitro transport across skin increased significantly after pretreatment (flux 7.05 μg/cm²/h) as compared to the untreated skin (flux 1.72 μg/cm²/h) and the enhanced delivery was also demonstrated in vivo in hairless rats. Conclusion Maltose microneedles were characterized and shown to create microchannels in the skin, which were also characterized and shown to improve the transdermal delivery of NH.     

Fabrication and characterisation of self-applicating heparin sodium microneedle patches

Abstract

The aim of this study was to develop heparin sodium loaded microneedle patches using different compositions of polyvinyl alcohol polymer and sorbitol. A vacuum micromolding technique was used to fabricate microneedle patches while heparin sodium was loaded into needle tips. Physical features of patches were evaluated by measuring thickness, width, folding endurance and swelling percentage. Patches were also characterised by optical microscopy and scanning electron microscopy to determine the microneedle length and surface morphologies. A preliminary assessment of the microneedle performance was studied by examining the in-vitro insertion to the parafilm and recording the in-vitro drug release profile. In-vivo activity of patches was confirmed by measuring activated partial thromboplastin time and histological examination of the micropierced skin tissues. Prepared patches were clear, smooth; uniform in appearance; with sharp pointed microprojections and remained intact after 1000 folding. The microneedles were stiffer in nature, as they reproduce microcavities in the parafilm membrane following hand pushing without any structural loss. Insertion study results showed successful insertion of microneedles into the parafilm. Disrupted stratum corneum evident from histological examination confirmed successful insertion of the microneedle without affecting the vasculature. In-vitro release study confirmed ～92% release of the loaded drug within 120?min. A significant prolongation of activated partial thromboplastin time (4 folds as compared to negative control) was recorded following the application of heparin sodium loaded microneedle patch onto rabbit skin. In conclusion microneedles are a valuable drug delivery system, benefiting the patients with minimal skin invasion and also allowing self-administration of heparin sodium in a sustained release manner for the management of chronic ailments.     

Role of mast cells in the induction of dry skin in a mouse model of rheumatoid arthritis

Purpose: Rheumatoid arthritis (RA) is known to induce dry skin as an extra-articular symptom. However, the mechanisms behind the induction are unclear. In this study, we utilized an arthritis mouse model to simulate RA to reveal the relationship between arthritis and dry skin.

Materials and methods: DBA/1JJmsSlc control mice (n?=?5) and DBA/1JJmsSlc collagen-induced arthritis mouse model (arthritis mice; n?=?5) were used. We measured transepidermal water loss (TEWL) and capacitance to reveal the effect of arthritis on skin barrier function. In addition, we measured the expression of biomarkers of skin barrier function.

Results: We found that the hind limb volume of the arthritis mice was higher than that of the control mice. Our results showed that the arthritis mice had higher TEWL and lower capacitance when compared to the control mice. When compared to that of the control mice, the skin of the arthritis mice was thicker with more leukocyte infiltration. In the skin of arthritis mice, we observed lower expression of type I and IV collagens, but higher expression of matrix metalloproteinases (MMP)-1 and -9 when compared to that of the control mice. The levels of mast cells, histamine, substance P, and tryptase were higher in the arthritis mice than in the control mice. This study showed that the arthritis mice exhibited a disruption of skin barrier function (i.e. dry skin), which was improved following treatment with a mast cell inhibitor.

Conclusions: Our results on mast cells suggested that an improvement of dry skin is important for RA management.     

Current aspects of formulation efforts and pore lifetime related to microneedle treatment of skin

Importance of the field: The efficacy of microneedles in the area of transdermal drug delivery is well documented. Multiple studies have shown that enhancement of skin permeation by means of the creation of microscopic pores in the stratum corneum can greatly improve the delivery rates of drugs. However, skin pretreatment with microneedles is not the only factor affecting drug transport rates. Other factors, including drug formulation and rate of micropore closure, are also important for optimizing delivery by this route.

Areas covered in this review: This review aims to highlight work that has been done in these areas, with an emphasis on drug formulation parameters that affect transdermal flux.

What the reader will gain: This review creates an appreciation for the many factors affecting microneedle-enhanced delivery. Most results clearly indicate that microneedle skin pretreatment by itself may have different effects on drug transport depending on the formulation used, and formulation characteristics have different effects on the transport through untreated skin and microneedle-treated skin. Several formulation approaches are reported to optimize microneedle-enhanced drug delivery, including co-solvent use, vesicular, nanoparticulate and gel systems.

Take home message: In addition to well-established factors that affect microneedle-assisted delivery (geometry, type of microneedle, etc.), formulation and pore viability are also critical factors that must be considered.     

Transdermal delivery of relatively high molecular weight drugs using novel self-dissolving microneedle arrays fabricated from hyaluronic acid and their characteristics and safety after application to the skin

The purpose of this study was to develop novel dissolving microneedle arrays fabricated from hyaluronic acid (HA) as a material and to improve the transdermal permeability of relatively high molecular weight drugs. In this study, fluorescein isothiocyanate-labeled dextran with an average molecular weight of 4 kDa (FD4) was used as a model drug with a relatively high molecular weight. The microneedle arrays significantly increased transepidermal water loss (TEWL) and reduced transcutaneous electrical resistance (TER), indicating that they could puncture the skin and create drug permeation pathways successfully. Both TEWL and TER almost recovered to baseline levels in the microneedle array group, and relatively small pathways created by the microneedles rapidly recovered as compared with those created by a tape stripping treatment. These findings confirmed that the microneedle arrays were quite safe. Furthermore, we found that the transdermal permeability of FD4 using the microneedle arrays was much higher than that of the FD4 solution. Furthermore, we found that the microneedle arrays were much more effective for increasing the amount of FD4 accumulated in the skin.These findings indicated that using novel microneedle arrays fabricated from HA is a very useful and effective strategy to improve the transdermal delivery of drugs, especially relatively high molecular weight drugs without seriously damaging the skin.     

Characterization of dry skin associating with type 2 diabetes mellitus using a KK-Ay/TaJcl mouse model

Purpose: Type 2 diabetes mellitus (DM) induces various dermatological conditions that can affect patient quality of life, including increased susceptibility to skin infections and dry skin. While the mechanisms that underlie the causes of dry skin in type 1?DM have been widely studied, how type 2?DM elicits similar effects is unclear. The purpose of this study was therefore to evaluate skin barrier and hydration function using a KK-A^y/TaJcl mouse model of type 2?DM.

Materials and methods: KK-A^y/TaJcl and control mice were housed separately for 4 weeks and then body weight, water intake, urine production, and blood glucose levels were measured. Skin barrier function was estimated by assessing transepidermal water loss (TEWL) and hydration levels of the stratum corneum. The expression levels of various skin biochemical factors were also examined by western blot, including type 1 collagen, mast cell tryptase, hyaluronic acid binding protein (HABP), and fibroblast protein S100A4.

Results: Compared to control mice, there was a marked increase in body weight, water intake, urine production, and blood glucose levels in the KK-A^y/TaJcl mice over the length of the experiment. Hydration levels in the stratum corneum were lower in KK-A^y/TaJcl mice compared to control mice, although TEWL was not significantly different between groups. We also found that hyaluronic acid binding protein expression was higher in KK-A^y/TaJcl mice, although other biochemical factors were the same.

Conclusions: These findings suggest that hyaluronic acid associates with the dry skin caused by type 2?DM. This contributes to understanding this phenomenon and may lead to better treatment options for patients in the future.     

Skin penetration enhancement by a microneedle device (Dermaroller) in vitro: Dependency on needle size and applied formulation

This study focused on the in vitro evaluation of skin perforation using a new microneedle device (Dermaroller^®) with different needle lengths (150, 500 and 1500 μm). The influence of the microneedle treatment on the morphology of the skin surface (studied by light and scanning electron microscopy), on the transepidermal water loss (TEWL) and on the penetration and permeation of hydrophilic model drugs was investigated using excised human full-thickness skin. Furthermore, invasomes – highly flexible phospholipid vesicles containing terpenes and ethanol as penetration enhancer – were compared with an aqueous solution.Elevated TEWL values were measured after Dermaroller^® treatment compared to untreated human skin with a gradual increase of the TEWL over the first hour whereas afterwards the TEWL values decreased probably caused by a reduction of the pore size with time. Skin perforation with the Dermarollers^® enhanced drug penetration and permeation for both formulations tested. Invasomes were more effective to deliver hydrophilic compounds into and through the skin compared to the aqueous drug solutions and the combination with skin perforation further enhanced drug penetration and permeation.In conclusion, Dermarollers^® being already commercially available for cosmetic purposes appear also promising for drug delivery purposes particularly those with medium (500 μm) and shorter (150 μm) needle lengths.     

In vivo assessment of safety of microneedle arrays in human skin

Microneedle arrays are promising devices for the delivery of drugs and vaccines into or the skin. However, little is known about the safety of the microneedles. In this study we obtained insight in the ability of microneedles to disrupt the skin barrier, which was evaluated by transepidermal water loss (TEWL). We also determined the safety in terms of skin irritation (skin redness and blood flow) and pain sensation. We applied microneedle arrays varying in length and shape on the ventral forearms of 18 human volunteers. An effect of needle length was observed, as TEWL and redness values after treatment with solid microneedle arrays of 400mum were significantly increased compared to 200mum. The blood flow showed a similar trend. Needle design also had an effect. Assembled microneedle arrays induced higher TEWL values than the solid microneedle arrays, while resulting in less skin irritation. However, for all microneedles the irritation was minimal and lasted less than 2h. In conclusion, the microneedle arrays used in this study are able to overcome the barrier function of the skin in human volunteers, are painless and cause only minimal irritation. This opens the opportunity for dermal and transdermal delivery of drugs and vaccines.     

Effect of microneedle on the pharmacokinetics of ketoprofen from its transdermal formulations

Non-invasive transdermal delivery using microneedle arrays was recently introduced to deliver a variety of large and hydrophilic compounds into the skin, including proteins and DNA. In this study, a microneedle array was applied to the delivery of a hydrophobic drug, ketoprofen, to determine if transdermal delivery in rats can be improved without the need for permeation enhancers. The ability of a microneedle to increase the skin permeability of ketoprofen was tested using the following procedure. A microneedle array was inserted into the lower back skin of a rat using a clip for 10 min. Subsequently, 24 mg/kg of a ketoprofen gel was loaded on the same site where the microneedle had been applied. Simultaneously, the microneedle was coated with 24 mg/kg of a ketoprofen gel, and inserted into the skin using a clip for 10 min. As a negative control experiment, only 24 mg/kg of the ketoprofen gel was applied to the shaved lower back of a rat. Blood samples were taken at the indicated times. The plasma concentration (C_p) was obtained as a function of time (t), and the pharmacokinetic parameters were calculated using the BE program. The group loaded with the microneedle coated with ketoprofen gel showed a 1.86-fold and 2.86-fold increase in the AUC and C_max compared with the ketoprofen gel alone group. These results suggest that a microneedle can be an ideal tool for transdermal delivery products.     

Microchannels created by sugar and metal microneedles: Characterization by microscopy,macromolecular flux and other techniques

The objective of this study was to investigate the feasibility of using microneedle technology to enhance transcutaneous permeation of human immunoglobulin G (IgG) across hairless rat skin. Microchannels created by maltose and metal (DermaRoller?) microneedles were characterized by techniques such as methylene blue staining, histological examination, and calcein imaging. Methylene blue staining and histological sections of treated skin showed that maltose microneedles and DermaRoller? breached the skin barrier by creating microchannels in the skin with an average depth of ～150 µm, as imaged by confocal microscopy. Calcein imaging and pore permeability index values suggested the uniformity of the created pores in microneedle-treated skin. Transdermal studies with IgG indicated a flux rate of 45.96 ng/cm²/h, in vitro, and a C_max of 7.27 ng/mL, in vivo, for maltose microneedles-treated skin while a flux rate of 353.17 ng/cm²/h, in vitro, and a C_max of 9.33 ng/mL, in vivo, was achieved for DermaRoller?-treated skin. Transepidermal water loss measurements and methylene blue staining, in vivo, indicated the presence of microchannels for upto 24 h, when occluded. In conclusion, the microchannels created by maltose microneedles and DermaRoller? resulted in the percutaneous enhancement of a macromolecule, human IgG. © 2009 Wiley-Liss, Inc. and the American Pharmacists Association J Pharm Sci 99: 1931–1941, 2010