Introduction Oral route is the most acceptable route

Introduction Oral route is the most acceptable route of drug administration. Solid dosage forms are popular because of its ease of administration, pain avoidance and self medication when compared to the parenteral dosage forms [1]. SVD is a FDA approved thymidine analogue and it is used in the treatment of HIV infections whether alone or in combination with other antiretroviral drugs. It inhibits the HIV nebivolol hcl enzyme thereby it affects the DNA synthesis. The drug has a very short half life of 1.30 h. However, patients receiving SVD develop dose dependent side effects like lactic acidosis and neuropathy. Reduction of total administered dose will reduces the dose dependent side effects. Converting the twice daily regimen to once daily sustained release formulation of SVD is desirable to reduce the frequency of administration, to improve the patient compliance and adherence and therefore enhances the antiretroviral therapy [2,3]. The drug is freely soluble in water and hence, the selection of suitable release retardant excipients is necessary for constant drug release rate and it can be achieved by sustained release drug delivery systems [4]. A considerable research has been done on the drug SVD for sustained release and mostly they were used HPMC and Eudragit as release retardants [2–4]. Hence, in the present study, an attempt has been made to develop once daily sustained release tablets of SVD for the treatment of HIV using release retardants like TG, SCMC and SA.
Experimental
Results and discussion
Conclusion The sustained release tablets of SVD were prepared by wet granulation method with TG, SA and SCMC as release retardants. It could be concluded from the results that the TG and SA failed to retard the drug release and the combination of SA and SCMC was not much effective against the formulation prepared with SCMC alone. Formulations with SCMC alone were showed the sustained release of drug from its dosage form which is due to the coating property of SCMC. The formulation F9 was best as it has minimum drug release initially (12.33%) and maximum drug release (98.34%) at the end of 14 h. Hence, there is a lot of scope for future in-vivo studies.
Introduction Schizophrenia is a severe and disabling mental illness. It affects approximately 1% of the population worldwide and it is a chronic, severe disorder, lacking curative treatment. The suicide rate in schizophrenia is as high as 9–13%, with the incidence of suicide attempt reaching 50% of diagnosed patients over a lifetime. The onset of schizophrenia usually occurs around 18–25 years of age and is often preceded by premorbid behavioral deviations, such as social withdrawal and affective changes [1]. The symptoms and severity can vary over individual with schizophrenia. The symptoms are commonly divided into three types, namely; positive symptoms, negative symptoms and cognitive deficits [2–4]. Noncompliance to antipsychotic drugs has been a major problem since long [5]. Noncompliant psychiatric patients suffered an almost double re-hospitalization from relapse, reducing quality of life and increased economic burden [6]. Noncompliance to antipsychotic drugs was mainly caused by their side effects [7], including dose-dependent cardiac arrest deaths [8] and extrapyramidal side effects. For schizophrenia, good tolerance is known to be associated with good compliance and a higher therapy success rate. Risperidone is a potent antipsychotic drug, structurally related to atypical antipsychotics. It is used in treatment of schizophrenia and acute bipolar mania. Risperidone has a low propensity of extrapyramidal side effects [9–13]. It is effective in treatment of both negative and positive symptoms of schizophrenia. For risperidone, a dose-related increase in extrapyramidal side effects was indeed observed [14,15]. There was a strong association between plasma levels of risperidone and its adverse effects [16,17]. The treatment of schizophrenia using oral antipsychotic drugs dates back to the mid-1950s. Administration of antipsychotics via the oral route offered various advantages such as easiness of administration and portability of medication [18–20]. The true challenge in the development of an oral controlled release drug delivery system is not just to sustain the drug release but also to prolong the presence of the dosage form within the gastrointestinal tract (GIT) until all the drug is completely released at the desired period of time. Furthermore, sustained release antipsychotic dosage form will be expected to give less Cmax and thus less extrapyramidal side effects.