These normatives established universally accepted principles in human research addressing privacy, confidentiality, autonomy, beneficence and non-maleficence, beneficiary, justice, intellectual property, information and consent, participation and voluntariness and scientific and ethical review of the research by ethics committee. Some of them will be discussed shortly in the following text of this section. The integrity of the principal investigator throughout the protocol development, research process and publication process of the study results, as well as clearly stated conflict of interest if there is any, are also ethical principles, generally required in all kinds of research.

Vulnerable (research) participants are not included in the research unless it is absolutely proven necessary. Vulnerable persons are those who are relatively (or absolutely) incapable of protecting their own interests. More formally, they may have insufficient power, intelligence, education, resources, strength or other needed attributes to protect their own interests. Individuals whose willingness to volunteer in a research study may be unduly influenced by the expectation, whether justified or not, being of benefits associated with participation, or of a retaliatory response from senior members of a hierarchy in the case of refusal to participate may also be considered vulnerable or explored subjects. Examples are members of a group with a hierarchical structure, such as medical, pharmacy, dental, and nursing students, subordinate hospital and laboratory personnel, employees of the pharmaceutical industry, members of the armed forces and persons kept in detention. Other vulnerable persons include patients with incurable diseases, people in nursing homes, unemployed or impoverished people, patients in emergency situations, ethnic minority groups, homeless people, nomads, refugees, minors and those incapable of giving consent. This list may not be exhaustive as there may be circumstances in which other groups are considered vulnerable, women for example, in an orthodox patriarchical society or adult young men having to ask a chieftain (Marshall 2007; Benatar 2002, 2004; Nuffield 2002; CIOMS 2012; WMA 2013; ICH 1996).

Research ethics committee (REC) is an independent multidisciplinary board of individuals who undertake the review of research protocols for ethical considerations. It is also known in local, regional and international regulations under different names: ethical review board (ERB), ethical review committee (ERC) are the most common used in Europe whereas in USA, this committee is known as human research ethics committee [HREC], institutional review board [IRB] (EC 2001; Garrard and Dawson 2005; CIOMS 2002; WMA 2005, WMA 2013; Council of Europe 2005; ICH 1996). The EU Directive on Clinical Trials defines a research ethics committee as: an independent body in a Member State, consisting of healthcare professionals and nonmedical members, whose responsibility it is to protect the rights, safety and wellbeing of human subjects involved in a trial and to provide public assurance of that protection, by, among other things, expressing an opinion on the trial protocol, the suitability of the investigators and the adequacy of facilities, and on the methods and documents to be used to inform trial subjects and obtain their informed consent (EC 2001). Most ECs review study protocols for a single institution, such as hospital, with or without academic affiliation, while some are centralized, and review protocols from more than one institution/clinic, which is very useful for multi-centred studies. Unfortunately they do not exist in many developing and poor-resource countries where much research is conducted nowadays. In some countries, protocols for studies are reviewed by hospital and faculty ethics committees which serve as research ethics committees (investigational boards) as well.

Informed consent is a decision to participate in research, taken by a competent individual who has received the necessary information and has adequately understood the information, and who, after considering the information, has reached the decision without having been subjected to coercion, undue influence or inducement, or intimidation. Involvement of uncompetent subjects are rarely needed for skin research in general, and could be justified for dermal and transdermal drug delivery studies, only if acceptable risk-benefit balance is estimated and predictable risks and burdens are indentified. In the case of some vulnerable subjects not legally competent, informed consent is obtained from the legal guardians or parents. In a case of subjects’ literacy, when written consent is not possible to obtain, an eye witness oral informed consent is recommended (WMA 2013; CIOMS 2002; NAFDAC 2009a, b; Nuffield 2007). An informed or valid consent must address to three questions: (1) does the potential participant have the capacity to consent requiring consideration of such issues as age, maturity, cognitive ability; (2) is the consent voluntary (i.e. is the decision made free from coercion, inducement, or intimidation including pressure from a family member); and (3) has the potential participant received sufficient information on which to base a decision? The CIOMS guidelines also stress that consent is not an event, but a process in which potential participants need to have time to study information, think about them and ask additional questions before being asked to make a decision. It is of absolute importance that information should be available in appropriate languages and written in a style that is understandable by patients, taking into consideration relevant factors, and including cultural and sometimes religious differences. Consent form should be easily understandable and in writing, that documents a potential participant’s consent to be involved in research and which describes the rights of an enrolled research participant. This form, in a clear and respectful manner, should include the following: title of research; researchers involved; research time frame; purpose of research; description of research; potential harms and benefits; treatment alternatives; statement of confidentiality; information and data to be collected; how long the data will be kept, how it will be stored and who can access it; any conflicts of interest; a statement of the participant’s right to withdraw from participation at any point without any circumstances; and declarative statement of understanding that a participant agrees to and signs. The consent form should be in a language that the potential participant understands and for those with limited literacy, the verbal communication of the consent document details should be provided along with proper documentation of consent, if it will be given (WMA 2013; CIOMS 2002; ICH 1996; DHHS 2012).

Ethics review and evaluation of the research must take into account at least three considerations: ethical challenges, the institutional requirements and the legal constraints. Applicable law and legal rules are not always consistent and they could differ greatly. Besides, adhering ethical principles to national regulations and translating and applying them to studies carried out in developing countries is sometimes difficult because of social and cultural environments. Marchall elaborated several recommendations for researchers in multinational studies conducted in developing countries. They are listed below: